zte lte fdd physical layer overview feature description

LTE FDD

Physical Layer Overview Feature Description

Dong.Yuexin

矩形


ZTE Confidential Proprietary © 2011 ZTE Corporation. All rights reserved. I

LTE FDD Physical Layer Overview Feature Description

Version Date Author Approved By Remarks

V1.0 2011-04-12 Tao Linan Not open to the third party.

V2.0 2011-09-07 Tao Linan Not open to the third party.

© 2011 ZTE Corporation. All rights reserved.

ZTE CONFIDENTIAL: This document contains proprietary information of ZTE and is not to be disclosed or used without the prior written permission of ZTE.

Due to update and improvement of ZTE products and technologies, information in this document is subjected to change without notice.


II © 2011 ZTE Corporation. All rights reserved. ZTE Confidential Proprietary

TABLE OF CONTENTS

1 Introduction ................................................................................................................ 1

2 Overview ..................................................................................................................... 1 2.1 Downlink Parts ............................................................................................................. 2 2.1.1 Orthogonal Frequency Division Multiplexing (OFDM) ................................................. 2 2.1.2 Orthogonal Frequency Division Multiplexing Access (OFDMA) .................................. 6 2.1.3 Downlink physical layer general descriptions .............................................................. 7 2.1.4 Downlink physical channels and physical signals ..................................................... 10 2.2 Uplink Parts................................................................................................................ 13 2.2.1 Single Carrier – Frequency Division Multiplexing Access (SC-FDMA) ..................... 13 2.2.2 Uplink physical layer general descriptions ................................................................. 15 2.2.3 Uplink physical channels and physical signals .......................................................... 16

3 Technical Description .............................................................................................. 17 3.1 Normal CP ................................................................................................................. 17 3.2 Extended CP .............................................................................................................. 17 3.3 PDSCH Resource Allocation ..................................................................................... 18 3.3.1 Resource Allocation Type 0 ....................................................................................... 18 3.3.2 Resource Allocation Type 1 ....................................................................................... 18 3.3.3 Resource Allocation Type 2 ....................................................................................... 19 3.4 PUSCH Frequency Hopping ...................................................................................... 20 3.4.1 Type 1 PUSCH Hopping ............................................................................................ 21 3.4.2 Type 2 PUSCH Hopping ............................................................................................ 22 3.4.3 Comparison of Type 1 and Type 2 PUSCH Hopping ................................................ 23 3.5 PRACH Format 0 ~ 3 ................................................................................................. 24 3.5.1 PRACH Formats ........................................................................................................ 24 3.5.2 CP and GT Duration .................................................................................................. 25 3.6 Uplink: QPSK/16QAM, Downlink: QPSK/16QAM/64QAM ........................................ 27 3.7 Uplink: 64QAM ........................................................................................................... 27 3.8 TX Diversity................................................................................................................ 28 3.8.1 Space-Frequency Block Codes (SFBCs) .................................................................. 28 3.8.2 Frequency Switched Transmit Diversity (FSTD) and its Combination with SFBC .... 29 3.9 Open-loop Spatial Multiplexing .................................................................................. 30 3.9.1 Introduction ................................................................................................................ 30 3.9.2 Cyclic Delay Diversity (CDD) ..................................................................................... 31 3.10 Closed-loop Spatial Multiplexing ............................................................................... 32 3.11 Closed-loop Spatial Multiplexing (Rank = 1) ............................................................. 33 3.12 Uplink RX Diversity with IRC ..................................................................................... 34 3.13 Uplink MU-MIMO ....................................................................................................... 34 3.14 PUCCH Blanking ....................................................................................................... 34

4 Configuration of Parameters ................................................................................... 36 4.1 Parameters related to the serving cell ....................................................................... 36 4.1.1 Parameter list related to the serving cell ................................................................... 36 4.1.2 Parameter configuration related to the serving cell ................................................... 36 4.2 Parameters related to baseband configuration.......................................................... 42 4.2.1 Parameter list related to baseband configuration ...................................................... 42 4.2.2 Parameter configuration related to baseband configuration ...................................... 42 4.3 Parameters related to physical uplink channel .......................................................... 45 4.3.1 Parameter list related to physical uplink channel ...................................................... 45 4.3.2 Parameter configuration related to physical uplink channel ...................................... 45 4.4 Parameters related to physical downlink channel ..................................................... 46


ZTE Confidential Proprietary © 2011 ZTE Corporation. All rights reserved. III

4.4.1 Parameter list related to physical downlink channel .................................................. 46 4.4.2 Parameter configuration related to physcial downlink channel ................................. 46

5 Glossary .................................................................................................................... 47

FIGURES

Figure 1 Spectral efficiency of OFDM compared to classical multicarrier modulation ................ 3 Figure 2 Serial-to-parallel conversion operation for OFDM ......................................................... 3 Figure 3 Effect of channel on signals with short and long symbol duration ................................. 4 Figure 4 OFDM Transmitter ......................................................................................................... 5 Figure 5 OFDM cyclic prefix insertion .......................................................................................... 5 Figure 6 OFDM receiver ............................................................................................................... 6 Figure 7 Example of resource allocation in a combined OFDMA/TDMA system ........................ 7 Figure 8 Definition of channel bandwidth and transmission bandwidth configuration for one E-

UTRA carrier .................................................................................................................. 8 Figure 9 Basic time-frequency resource structure of LTE (normal cyclic prefix case) ............... 10 Figure 10 PCFICH mapping to Resource Element Groups (REGs) ............................................ 11 Figure 11 Summary of downlink physical channels and mapping to higher layers ..................... 13 Figure 12 SC-FDMA frequency-domain transmit processing (DFT-S-OFDM) showing localized

and distributed subcarrier mapping ............................................................................. 14 Figure 13 Summary of uplink physical channels and mapping to higher layers .......................... 16 Figure 14 PRB addressed by a bitmap Type 0, each bit addressing a complete RBG ............... 18 Figure 15 PRBs addressed by a bitmap Type 1, each bit addressing a subset of a RBG,

depending on a subset selection and shift value ......................................................... 19 Figure 16 Type 1 intra-subframe PUSCH hopping ...................................................................... 22 Figure 17 Hopping bandwidth is divided into equal sub-bands to perform sub-band based

hopping ........................................................................................................................ 23 Figure 18 Type 2 intra and inter-subframe PUSCH hopping ....................................................... 23 Figure 19 PRACH preamble received at the eNodeB.................................................................. 25 Figure 20 PRACH preamble received at the eNodeB.................................................................. 26 Figure 21 PRACH preamble formats and cell size dimensioning ................................................ 27 Figure 22 Data modulation (QPSK: L = 2, 16QAM: L = 4, 64QAM: L = 6) .................................. 27 Figure 23 Overview of physical channel processing with MIMO ................................................. 31 Figure 24 Principle of Cyclic Delay Diversity ............................................................................... 32 Figure 25 Rank-1 transmission .................................................................................................... 34 Figure 26 PUCCH blanking (over-provisioned PUCCH) .............................................................. 35

TABLES

Table 1 Summary of key performance requirement targets for LTE .......................................... 1 Table 2 Transmission bandwidth configuration BWconfig in LTE channel bandwidths ............. 8 Table 3 Three configurations for LTE ......................................................................................... 9 Table 4 DCI formats .................................................................................................................. 12


IV © 2011 ZTE Corporation. All rights reserved. ZTE Confidential Proprietary

Table 5 Mapping of downlink control channel information to physical channel ........................ 12 Table 6 LTE uplink SC-FDMA physical layer parameters ........................................................ 15 Table 7 LTE uplink SC-FDMA parameters for selected carrier bandwidths ............................. 15 Table 8 RBG size for Type 0 resource allocation ..................................................................... 18 Table 9 LTE uplink SC-FDMA parameters for selected carrier bandwidths ............................. 21 Table 10 Random access preamble formats .............................................................................. 25 Table 11 Cell radius of PRACH preamble formats ..................................................................... 26 Table 12 Categories of LTE UE .................................................................................................. 28 Table 13 Codeword-to-layer mapping ........................................................................................ 31 Table 14 Precoder matrices in case of two antenna ports ......................................................... 32


ZTE Confidential Proprietary © 2011 ZTE Corporation. All rights reserved. 1

1 Introduction This document provides a high-level description of LTE physical layer features available in the ZTE LTE FDD products. The document also contains parameter related to these features.

Abbreviations used in this document are explained in Glossary.

Related physical layer procedures can be found in ‘ZTE LTE FDD Physical Layer Procedures Feature Descriptions’.

2 Overview This chapter outlines the necessary LTE physical layer concepts. These concepts are as follows,

• Downlink parts

− Orthogonal Frequency Division Multiplexing (OFDM)

− Orthogonal Frequency Division Multiplexing Access (OFDMA)

− Downlink physical layer general descriptions

− Downlink physical channels and physical signals

• Uplink parts

− Single Carrier – Frequency Division Multiplexing Access (SC-FDMA)

− Uplink physical layer general descriptions

− Uplink physical channels and physical signals

Table 1 summarizes the main performance requirements to which the first release of LTE was designed, which leads the adoption of OFDMA (for downlink) and SC-FDMA (for uplink) in LTE.

Table 1 Summary of key performance requirement targets for LTE

Absolute requirements

Comparison to Release 6

Comments

Downlink

Peak transmission rate

> 100Mbps 7*14.4 Mbps LTE in 20MHz FDD, 2*2 spatial multiplexing. Reference: HSDPA in 5MHz FDD, single antenna transmission

Peak spectral efficiency

> 5 bps/Hz 3 bps/Hz

Average cell > 1.6 ~ 2.1 3 ~ 4 * 0.53 LTE: 2*2 spatial


2 © 2011 ZTE Corporation. All rights reserved. ZTE Confidential Proprietary

spectral efficiency

bps/Hz/Cell bps/Hz/cell multiplexing; Reference: HSDPA, rake receiver, 2 receive antennas

Cell edge spectral efficiency

> 0.04 ~ 0.06 bps/Hz/user

2 ~ 3 * 0.02 bps/Hz

As above 10 users assumed per cell

Uplink

Peak transmission rate

> 50Mbps 5*11 Mbps LTE in 20MHz FDD, single antenna transmission. Reference: HSUPA in 5MHz FDD, single antenna transmission

Peak spectral efficiency

> 2.5 bps/Hz 2 bps/Hz

Average cell spectral efficiency

> 0.66 ~ 1.0 bps/Hz/Cell

2 ~ 3 * 0.33 bps/Hz/cell

LTE: single antenna transmission, Reference: HSUPA, rake receiver, 2 receive antenna

Cell edge spectral efficiency

> 0.02 ~ 0.03 bps/Hz/user

2 ~ 3 * 0.01 bps/Hz

As above, 10 users assumed per cell

System

User plane latency (two way radio delay)

<10ms One fifth

Connection setup latency

<100ms Idle state -> active state

Operating bandwidth

1.4 ~ 20MHz 5MHz Initial requirement started at 1.25MHz

VoIP capacity NGMN preferred target is > 60 sessions/MHz/cell.

2.1 Downlink Parts

2.1.1 Orthogonal Frequency Division Multiplexing (OFDM)

In general, multicarrier schemes subdivide the used channel bandwidth into a number of parallel sub-channels as shown in the following Figure 1(a). Ideally the bandwidth of each subchannel is such that they are each non-frequency-selective (i.e. having a spectrally-flat gain). This has the advantage that the receiver can easily compensate for the subchannel gains individually in the frequency domain.

OFDM is a special case of multicarrier transmission. In OFDM, the non-frequency-selective narrowband subchannels into which the frequency-selective wideband channel is divided are overlapping but orthogonal, as shown in Figure 1(b). This avoids the need to separate the carriers by means of guard-bands, and therefore makes OFDM highly spectrally efficient. The spacing between the subchannels in OFDM is such they can be perfectly separated at the receiver. This allows for a low-complexity receiver implementation, which makes OFDM attractive for high-rate mobile data transmission such as the LTE downlink.



Figure 1 Spectral efficiency of OFDM compared to classical multicarrier modulation

Guard-band

(a) Classical multi-carrier system spectrum

Saving in spectrum

(b) OFDM system spectrum

A high-rate data stream typically faces a problem in having a symbol period Ts much smaller than the channel delay spread Td if it is transmitted serially. This generates Inter-symbol Interference (ISI) which can only be undone by means of a complex equalization procedure. In general, the equalization complexity grows with the square of the channel impulse response length.

In OFDM, the high-rate stream of data symbols is first serial-to-parallel converted for modulation onto M parallel subcarriers as shown in Figure 2. This increases the symbol duration on each subcarrier by a factor of approximately M, such that it becomes significantly longer than the channel delay spread.

Figure 2 Serial-to-parallel conversion operation for OFDM

S/P

High symbol rate

Low symbol rate

…………

exp(-j*2*pi*t*f1)

exp(-j*2*pi*t*fM)P/S

This operation has the important advantage of requiring a much less complex equalization procedure in the receiver, under the assumption that the time-varying channel impulse response remains substantially constant during the transmission of each modulated OFDM symbol. Figure 3 shows how the resulting long symbol duration is virtually unaffected by ISI compared to the short symbol duration, which is highly corrupted.



Figure 3 Effect of channel on signals with short and long symbol duration

Signal

Symbol periodTS

Channel convolution

TD < TS (long symbol duration low-rate signal)

TD > TS (short symbol duration high-rate signal)

Inter-symbol interference

Delay spreadTD

Figure 4 shows the typical block diagram of an OFDM transmitter. The signal to be transmitted is defined in the frequency domain.

• A Serial to Parallel (S/P) converter collects serial data symbol into a data block Sk = [Sk[0], Sk[1], …, Sk[M -1]]T of dimension M, where the subscript k is the index of an OFDM symbol (spanning the M subcarriers).

• The M parallel data streams are first independently modulated resulting in the complex vector Xk = [Xk[0], Xk[1], …, Xk[M -1]]T. (Note that in principle it is possible to use different modulations (e.g. QPSK, 16QAM or 64QAM) on each subcarrier; due to channel frequency selectivity, the channel gain may differ between subcarriers, and thus some subcarriers can carry higher data-rates than others).

• The vector of data symbol Xk then passes through an Inverse FFT (IFFT) resulting in a set of N complex time-domain samples xk = [xk[0], xk[1], …, xk[N -1]]T. In a practical OFDM system, the number of processed subcarriers is greater than the number of modulated subcarriers (i.e. N>=M), with the un-modulated subcarriers being padded with zeros.

• The following key operation in the generation of an OFDM signal is the creation of a guard period at the beginning of each OFDM symbol, to eliminate the remaining impact of ISI caused by multipath propagation. The guard period is obtained by adding a Cyclic Prefix (CP) at the beginning of the symbol xk. The CP is generated by duplicating the last G samples of the IFFT output and appending them at the beginning of xk. This yields the time domain OFDM symbol [xk[N - G], …, xk[N -1], xk[0], xk[1], …, xk[N -1]]T as shown in Figure 5.



Figure 4 OFDM Transmitter

S/P

Sk[0]

Sk[1]

Sk[M-2]

Sk[M-1]

Xk[0]

Xk[1]

Xk[M-2]

Xk[M-1]

IFFT

Zero-padding

…

…

Zero-padding…

P/S

xk[0]

xk[1]

xk[N-G]

xk[N-1]

…

xk[N-G]

xk[N-1]

…

………

Cyclic Prefix

DAC

Figure 5 OFDM cyclic prefix insertion

TCP TU TCP TU TCP TU

At the receiver, the reverse operations are performed to demodulate the OFDM signal. Assuming that time and frequency synchronization is achieved, a number of samples corresponding to the length of the CP are removed, such that only an ISI-free block of samples is passed to the DFT. If the number of subcarriers N is designed to be a power of 2, a highly efficient FFT implementation may be used to transform the signal back to the frequency domain. Among the N parallel streams output from the FFT, the modulated subset of M subcarriers are selected and further processed by the receiver as shown in Figure 6.

Let x(t) be the signal symbol transmitted at time instant t. The received signal in a multipath environment is then given by

)()()()( tzthtxtr +∗=

Where

• h(t) is the continuous-time impulse response of the channel;

• * represents the convolution operation;

• z(t) is the additive noise;



Figure 6 OFDM receiver

ADC S/P

rkCP[0]

rkCP[G-1]

…

rkCP[G] = rk[0]

rkCP[G+1] = rk[1]

rkCP[N+G-2] = rk[N-2]

rkCP[N+G-1] = rk[N-1]

FFT

Yk[0]

Yk[1]

Yk[N-2]

Yk[N-1]

Cyclic Prefix Removal

The CP of OFDM changes the linear convolution into a circular one. The circular convolution is very efficiently transformed by means of an FFT into a multiplicative operation in the frequency domain. Hence, the transmitted signal over a frequency-selective (i.e. multipath) channel is converted into a transmission over N parallel flat-fading channels in the frequency domain:

][][][][ mZmHmXmR +⋅=

As a result the equalization is much simpler than for single-carrier systems and consists of just one complex multiplication per subcarrier.

2.1.2 Orthogonal Frequency Division Multiplexing Access (OFDMA)

Orthogonal Frequency Division Multiple Access (OFDMA) is an extension of OFDM to the implementation of a multi-user communication system. In the discussion above, it has been assumed that a single user receives data on all the subcarriers at any given time. OFDMA distributes subcarriers to different users at the same time, so that multiple users can be scheduled to receive data simultaneously. Usually, subcarriers are allocated in contiguous groups for simplicity and reduce the overhead of indicating which subcarriers have been allocated to each user.

OFDMA can also be used in combination with Time Division Multiple Access (TDMA), such that the resources are partitioned in the time-frequency plane – i.e. groups of subcarriers for one specific time duration. In LTE, such time-frequency blocks are known as Resource Blocks (RBs), as explained in 2.1.3.2. Figure 7 depicts such an OFDMA/TDMA mixed strategy as used in LTE.



Figure 7 Example of resource allocation in a combined OFDMA/TDMA system

User 1 User 2 User 3 User 4

Freq

uenc

y

Time

2.1.3 Downlink physical layer general descriptions

A major design goal for the LTE system is flexible bandwidth support for deployments in diverse spectrum arrangement. With this objective in mind, the physical layer of LTE is designed to support bandwidths in increments of 180 kHz starting from a minimum bandwidth of 1.08MHz.

In order to support channel sensitive scheduling and to achieve low packet transmission latency, the scheduling and transmission interval is defined as a 1ms subframe.

Two CP lengths namely normal cyclic prefix and extended cyclic prefix are defined to support small and large cells deployments respectively.

A subcarrier spacing of 15kHz is to chosen to strike a balance between cyclic prefix overhead and robustness to Doppler spread. An additional smaller 7.5kHz subcarrier spacing is defined for Multimedia Broadcast Single Frequency Network (MBSFN) to support large delay spreads with reasonable cyclic prefix overhead.

2.1.3.1 Channel Bandwidths

The LTE system supports a set of six channel bandwidth as given in Table 2. Note that the transmission bandwidth configuration BWconfig is 90% of the channel bandwidth BWchannel for 3~20MHz. For 1.4MHz channel bandwidth, the transmission bandwidth is only 77% of the channel bandwidth. Therefore, LTE deployment in the small 1.4MHz is less spectrally efficient than the 3~20MHz bandwidths.

The relationship between the channel bandwidth BWchannel and the transmission bandwidth configuration DL

RBN is shown in Figure 8. The transmission bandwidth configuration in MHz is given as:

∆××=

1000fNNBW

RBSC

DLRB

config



Where

• DLRBN is downlink bandwidth configuration, expressed in multiples of RB

SCN .

• RBSCN is RB size in the frequency domain, expressed as a number of subcarriers. In

this version, it’s 12.

• f∆ is subcarrier spacing, 15kHz or 7.5kHz.

Table 2 Transmission bandwidth configuration BWconfig in LTE channel bandwidths

Channel bandwidth BWchannel [MHz]

Downlink transmission bandwidth configuration DL

RBN Transmission bandwidth configuration BWconfig [MHz]

1.4 6 1.08

3 15 2.7

5 25 4.5

10 50 9.0

15 75 13.5

20 100 18.0

Figure 8 Definition of channel bandwidth and transmission bandwidth configuration for one E-UTRA carrier

Transmission Bandwidth [RB]

Transmission Bandwidth Configuration [RB]

Channel Bandwidth [MHz]

Center subcarrier (corresponds to DC in

baseband) is not transmitted in downlink Active Resource Blocks

Channel edge

Channel edge

Resource block

The channel edges are defined as the lowest and highest frequencies of the carrier separated by the channel bandwidth, i.e. at

channelC BWF ±

Where



• FC is the carrier center frequency.

The spacing between carriers depends on the deployment scenario, the size of the frequency block available and the channel bandwidths. The nominal channel spacing between two adjacent E-UTRA carriers is defined as following:

( )2

(2)(1)min

channelchannelalno

BWBWΔf

+=

Where BWchannel(1) and BWchannel(2) are the channel bandwidths of the two respective E-UTRA carriers. The channel spacing can be adjusted to optimize performance in a particular deployment scenario. The channel raster is 100kHz, which means that the carrier center frequency is always an integer multiple of 100kHz.

Parameters related to channel bandwidth are as follows. Please refer to section 4.1.2.11 and 4.1.2.12 for detailed information.

1) Downlink system bandwidth: it indicates the downlink bandwidth in RB.

2) Uplink system bandwidth: it indicates the uplink bandwidth in RB.

2.1.3.2 Frame and slot structure

In the LTE system, uplink and downlink data transmissions are scheduled on one 1 ms subframe basis. A subframe consists of two equal duration (0.5 ms) consecutive time slots with subframe number i consisting of slots 2i and (2i + 1). All the time durations are defined in terms of the sample period Ts = 1/fs, where fs = 30.72 Msamples/sec. Some of the control signals such as synchronization and broadcast control in the downlink are carried on a 10ms radio frame basis, where a radio frame is defined to consist of 10 subframes as shown in Figure 9. The transmission of the uplink radio frame number i from a UE starts NTA*Ts seconds before the start of the corresponding downlink radio frame at the UE, where NTA represents the timing offset between uplink and downlink radio frames at the UE in units of Ts. This timing offset NTA is adjusted for each UE in order to make sure that signals from multiple UEs transmitting on the uplink arrive at the eNodeB at the same time. Each slot is further divided into UL

symbN SC-FDMA symbols or DLsymbN OFDM symbols for the uplink and downlink respectively. A resource element is

one subcarrier in a single OFDM or SC-FDMA symbol as shown in Figure 9. A resource element is defined by the index pair (k, l) in a slot, where k and l are the subcarrier and OFDM/SC-FDMA symbol index respectively.

There are 3 different configurations to parameterize the lengths of the different fields in the slots and symbols shown in Table 3. These configurations are relating to different deployment scenarios of LTE. The UE has to identify which of these 3 configurations is used during initial cell search by try and error.

Table 3 Three configurations for LTE

Configuration Delta_f (kHz)

Symbols per slot

CP length FFT length

Normal 15 7 160 samples (5.2us) for first symbol 144 samples (4.7us) for other symbols

2048



Extended CP 15 6 512 samples (16.67us) 2048

Extended CP (DL only)

7.5 3 1024 samples (33us) 4096

Figure 9 Basic time-frequency resource structure of LTE (normal cyclic prefix case)

0 1 18 192 3

Tslot = 15360*Ts = 0.5ms

0 1 18 192 3 17

Uplink

Tsubframe = 30720*Ts = 1ms

One radio frame, Tf = 307200 * Ts = 10ms

Downlink

(NTA*TS)

………...

………...

NS

CR

B s

ub-c

arrie

rs

NR

BU

L *N

SC

RB s

ub-c

arrie

rs

l = 0 l = NsymbUL -1

NR

BD

L *NS

CR

B sub-carriers

l = 0 l = NsymbDL -1

Resource Block (RB)

Resource Element (k, l)

Parameters related to cyclic prefix is as follows. Please refer to section 4.1.2.7 for detailed information.

1) CP Selection for Physical Channel: it indicates the cyclic prefix type used in the cell.

2.1.4 Downlink physical channels and physical signals

There are totally 3 physical data-transporting channels:

• Physical Broadcast Channel (PBCH): used to transmit ‘Master Information Block (MIB)’, which consists of a limited number of the most frequently transmitted parameters essential for initial access to the cell.



• Physical Downlink Shared Channel (PDSCH): used for all user data, as well as for broadcast system information which is not carried on the PBCH, and for paging messages – there is no specific physical layer paging channel in the LTE system.

• Physical Multicast Channel (PMCH): used for MBMS (Multimedia Broadcast and Multicast Services.

There are totally 3 physical control channels:

• Physical Control Format Indicator Channel (PCFICH): used to carry a Control Format Indicator (CFI) which indicates the number of OFDM symbols (i.e. normally 1, 2 or 3) used for transmission of control channel information in each subframe. The PCFICH is transmitted on the same set of antenna ports as PBCH, with transmit diversity being applied if more than one antenna port is used. In order to achieve frequency diversity, the 16 resource elements carrying PCFICH are distributed across the frequency domain. This is done according to a predefined pattern in the first OFDM symbol in each downlink subframe (see figure **), so that the UEs can always locate the PCFICH information. This is prerequisite to being able to decode the rest of the control signaling. To minimize the possibility of confusion with PCFICH information from a neighbouring cell, a cell-specific frequency offset is applied to the positions of the PCFICH resource elements. This offset depends on the Physical Cell ID (PCI).

Figure 10 PCFICH mapping to Resource Element Groups (REGs)

PCFICH resource elements

time

Resource elements reserved for reference symbols

One REG

frequency

Parameter related to PCFICH is as follows. Please refer to section 4.1.2.18 and section 4.1.2.4 for detailed information.

1) CFI Selection: three different CFI values are used in LTE and a fourth codeword is reserved for further use.

2) Physical Cell ID: There are 504 unique physical-layer cell identities. The physical-layer cell identities are grouped into 168 unique physical-layer cell-identity groups, each group containing three unique identities.

• Physical Downlink Control Channel (PDCCH): used to carry a message known as Downlink Control Information (DCI), which includes resource assignments and other control information for a UE or group of UEs. In general, several PDCCHs can be transmitted in a subframe. The information content of the different DCI message formats is listed in Table 4.



Table 4 DCI formats

DCI format Purpose 0 PUSCH grants

1 PDSCH assignments with a single codeword

1A PDSCH assignments using a compact format

1B PDSCH assignments for rank-1 transmission

1C PDSCH assignments using a very compact format

1D PDSCH assignments for multi-user MIMO

2 PDSCH assignments for closed-loop MIMO

2A PDSCH assignments for open-loop MIMO

3 Transmit Power Control (TPC) commands for multiple users for PUCCH and PUSCH with 2-bit power adjustments.

3A Transmit Power Control (TPC) commands for multiple users for PUCCH and PUSCH with 1-bit power adjustments.

• Physical Hybrid ARQ Indicator Channel (PHICH): used to carry the HARQ ACK/NACK, which indicates whether the eNodeB has correctly received a transmission on the PUSCH.

Parameter related to PHICH is as follows. Please refer to section 4.4.2.1 and section 4.4.2.2 for detailed information.

1) Factor of PHICH group: The Number of PHICH Group determines the number of PHICHs allocated for UEs in the cell. A PHICH group consists of multiple PHICH.

2) PHICH duration: The duration of PHICH determines how many OFDM symbols that PHICH will be mapped on.

The downlink physical channels are summarized in Figure 11 together with their relationship to the higher-layer channels. Table 5 specifies the mapping of the downlink control channel information to its corresponding physical channel.

Table 5 Mapping of downlink control channel information to physical channel

Control Information Physical Channel CFI PCFICH

HI PHICH

DCI PDCCH



Figure 11 Summary of downlink physical channels and mapping to higher layers

Downlink logical channels

CCCH DCCH DTCH

PCHDownlink transport channels

PMCHPDSCHPBCH

Downlink physical channels

PCCH BCCH MCCH MTCH

BCH DL-SCH MCH

PCFICH PDCCH PHICH

MIB

Other SI

MBSFNSingle cell MBMS

There are totally two kinds of downlink physical signals:

• Reference Signals (RS):

− Cell-specific RS: often referred to as ‘common’ RS, as they are available to all UEs in a cell;

− UE-specific RS: which may be embedded in the data for specific UEs;

− MBSFN-specific RS: which are only used for Multimedia Broadcast Single Frequency Network (MBSFN) operation;

• Synchronization signals:

− Primary Synchronization Signal (PSS): used for the detection of slot timing and physical layer ID;

− Secondary Synchronization Signal (SSS): used for the detection of radio frame timing, cell ID, cyclic prefix length, TDD/FDD detection.

2.2 Uplink Parts

2.2.1 Single Carrier – Frequency Division Multiplexing Access (SC-FDMA)

The multiple access scheme selected for the LTE uplink is SC-FDMA. A major advantage of SC-FDMA over the Direct Sequence-Code Division Multiple Access (DS-CDMA) scheme used in UMTS is that it achieves intra-cell orthogonal even in frequency-selective channels. SC-FDMA avoids the high level of intra-cell interference associated with DS-CDMA which significantly reduces system capacity and limits the use of adaptive modulation. SC-FDMA combines the desirable characteristics of OFDM with the low CM/PAPR (Cubic Metric / Peak-to-Average Power Ratio) of single-carrier transmission schemes as follows.

• Like OFDM, SC-FDMA divides the transmission bandwidth into multiple parallel subcarriers, with the orthogonality between the subcarriers being maintained in frequency-selective channels by the use of a CP or guard period.



• Unlike OFDM, the signal modulated onto a given subcarrier in SC-FDMA is a linear combination of all the data symbols transmitted at the same time instant. Thus in each symbol period, all the transmitted subcarriers of an SC-FDMA signal carry a component of each modulated data symbol. This gives SC-FDMA its crucial single-carrier property, which results in the CM/PAPR being significantly lower than pure multicarrier transmission schemes such as OFDM.

Time domain generation of an SC-FDMA signal is shown in Figure 12. It can be seen to be similar to conventional single-carrier transmission.

• The first step of DFT-S-OFDM (DFT-Spread OFDM) SC-FDMA signal generation is to perform an M-point DFT operation on each block of M QAM data symbols.

• Zeros are then inserted among the outputs of the DFT in order to match the DFT size to an N-subcarrier OFDM modulator (typically an Inverse Fast Fourier Transform (IFFT)).

• The zero-padded DFT output is mapped to the N subcarriers, with the positions of the zeros determining to which subcarriers the DFT-precoded data is mapped.

Figure 12 SC-FDMA frequency-domain transmit processing (DFT-S-OFDM) showing localized and distributed subcarrier mapping

Serial to Parallel

converter

Bit to Constellation

Mapping

M-point DFT

Spreading


Mapping


Mapping

m bits

m bits

m bits

x(0,n)

x(1,n)

x(M-1,n)

Subcarrier Mapping

f0

f1

fM-1

Localized Subcarrier Mapping

f0f1

fM-1

f2f3

fM-4

fM-3

fM-2

00

0

0

00

0

0

Distributed Subcarrier Mapping

f0f1

fM-1

f2f3

fM-4

fM-3

fM-2

00

00

00

00

00

00

Frequency Frequency

N-point IFFT

Add Cyclic Prefix

Parallel to Serial

Converter

Incoming Bit Stream

As with the time-domain approach, DFT-S-OFDM is capable of generating both localized and distributed transmissions:



• Localized transmission: The subcarrier mapping allocates a group of M adjacent subcarriers to a user. M <N results in zero being appended to the output of the DFT spreader resulting in an upsampled/interpolated version of the original M QAM data symbols at the IFFT output of the OFDM modulator.

• Distributed transmission: The subcarrier mapping allocates M equally-spaced subcarriers (e.g. every Lth subcarrier). (L − 1) zeros are inserted between the M DFT outputs, and additional zeros are appended to either side of the DFT output prior to the IFFT (ML< N). As with the localized case, the zeros appended on either side of the DFT output provide upsampling, while the zeros inserted between the DFT outputs produce waveform repetition in the time domain.

2.2.2 Uplink physical layer general descriptions

Frequency-domain signal generation for the LTE uplink has a benefit in that is allows a very similar parameterization to be adopted as for the OFDM downlink, including the same subcarrier spacing, number of occupied subcarriers in a given bandwidth, and CP length. This provides maximal commonality between uplink and downlink, including for example the same clock frequency as shown in Table 6.

Table 6 LTE uplink SC-FDMA physical layer parameters

Parameter Value Description Subframe duration 1ms 1 subframe includes 2 slots. Slot duration is 0.5ms.

Subcarrier spacing 15kHz

SC-FDMA symbol duration 66.67us

CP duration Normal CP 5.2us first symbol in each slot;

4.7us all other symbols

Extended CP 16.67us all symbols

Number of symbols per slot 7 (Normal CP) 6 (Exteneded CP)

Number of subcarriers per RB 12 Resource block size in the frequency domain

Like the downlink, the LTE uplink supports scalable system bandwidths from approximately 1.4MHz up to 20MHz with the same subcarrier spacing and symbol duration for all bandwidths. The uplink scaling for the bandwidth is shown in Table 7.

Table 7 LTE uplink SC-FDMA parameters for selected carrier bandwidths

Carrier bandwidth (MHz) 1.4 3 5 10 15 20 FFT size 128 256 512 1024 1536 2048

Number of subcarriers 72 180 300 600 900 1200

Number of RBs 6 15 25 50 75 100

Bandwidth efficiency (%) 77.1 90 90 90 90 90



2.2.3 Uplink physical channels and physical signals

The physical layer transmissions of the LTE uplink are comprised of three physical channels and two signals and summarized in Figure 13.

• Physical Random Access Channel (PRACH): used to carrier Random Access Channel (RACH) to achieve uplink time synchronization for a UE which either has not yet acquired, or has lost, its uplink synchronization.

• Physical Uplink Shared Channel (PUSCH): used to carry data from the Uplink Shared Channel (UL-SCH) transport channel.

• Physical Uplink Control Channel (PUCCH): used to carrier uplink control signaling not associated with uplink data, transmitted independently of any uplink data packet. Control signaling includes:

− HARQ Acknowledgements (ACK/NACK) for downlink data packets,

− Channel Quality Indicators (CQI),

− MIMO feedback (such as Rank Indicator (RI) and/or Precoding Matrix Indicator (PMI)) for downlink transmissions,

− Scheduling Requests (SRs) for uplink transmissions.

• DeModulation Reference Signal (DMRS): associated with transmission of uplink data on the PUSCH and/or control signaling on PUCCH. These reference signals are primarily used for channel estimation for coherent demodulation.

• Sounding Reference Signal (SRS): not associated with uplink data and/or control transmissions, and primarily used for channel quality determination to enable frequency-selective scheduling on the uplink.

Figure 13 Summary of uplink physical channels and mapping to higher layers

Uplink logical channels

CCCH DCCH DTCH

UL-SCHRACHUplink transport channels

PUSCHPRACHPUCCH

Uplink physical channels



3 Technical Description

3.1 Normal CP As already mentioned in the overview of the LTE radio access provided in section 2.1, LTE downlink transmission is based on OFDM. The basic LTE downlink physical resource can thus be seen as a time-frequency resource grid as shown in Figure 9, where each resource element corresponds to one OFDM subcarrier during one OFDM symbol interval.

As shown in Table 3, LTE defines two cyclic-prefix lengths, the normal cyclic prefix and an extended cyclic prefix, corresponding to seven and six OFDM symbols per slot, respectively. It can be noted that, in case of the normal cyclic prefix, the cyclic-prefix length for the first OFDM symbol of a slot is somewhat larger, compared to the remaining OFDM symbols. The reason for this is simply to fill the entire 0.5 ms slot as the number of basic time units Ts per slot (15360) is not dividable by seven.

Taking into account also the downlink time-domain structure, the resource blocks mentioned above consist of 12 subcarriers during a 0.5-ms slot, as illustrated in Figure 9. Each resource block thus consists of 84 resource elements in case of normal cyclic prefix and 72 resource elements in case of extended cyclic prefix.

3.2 Extended CP The reasons for defining two cyclic-prefix lengths for LTE are twofold:

• A longer cyclic prefix, although less efficient from a cyclic-prefix-overhead point-of-view, may be beneficial in specific environments with very extensive delay spread, for example in very large cells. It is important to have in mind, though, that a longer cyclic prefix is not necessarily beneficial in case of large cells, even if the delay spread is very extensive in such cases. If, in large cells, link performance is limited by noise rather than by signal corruption due to residual time dispersion not covered by the cyclic prefix, the additional robustness to radio-channel time dispersion, due to the use of a longer cyclic prefix, may not justify the corresponding loss in terms of reduced received signal energy.

• In case of MBSFN-based multicast/broadcast transmission, the cyclic prefix should not only cover the main part of the actual channel time dispersion but also the timing difference between the transmissions received from the cells involved in the MBSFN transmission. In case of MBSFN operation, the extended cyclic prefix is therefore often needed.

Thus, the main use of the extended cyclic prefix can be expected to be MBSFN-based transmission.



3.3 PDSCH Resource Allocation Conveying indications of physical layer resource allocation is one of the major functions provided by the PDCCHs. There are three resource allocation methods given below.

3.3.1 Resource Allocation Type 0

In resource allocations of Type 0, a bitmap indicates the Resource Block Groups (RBGs) which are allocated to the scheduled UE, where a RBG is a set of consecutive PRBs. The RBG size (P) is a function of the system bandwidth as shown in Table 8. The total number of RBGs (NRBG) for a downlink system bandwidth of RB

DLN PRBs is given by

PNN RBDLRBG /= . An example for the case of RB

DLN = 25, NRBG = 13 and P = 2 is shown in Figure 14, where each bit in the bitmap indicates a pair of PRBs (i.e. two PRBs which are adjacent in frequency).

Table 8 RBG size for Type 0 resource allocation

System bandwidth RBDLN System bandwidth RBG size (P)

0 ~ 10 1.4MHz 1 11 ~ 26 3MHz, 5MHz 2 27 ~ 63 10MHz 3 64 ~ 110 15MHz, 20MHz 4

Figure 14 PRB addressed by a bitmap Type 0, each bit addressing a complete RBG

PRB1

PRB2

PRB3

PRB4

PRB5

PRB6

PRB7

PRB8

PRB9

PRB19

PRB20

PRB21

PRB22

PRB23

PRB24

PRB25

PRB10

RBG 1 RBG 2 RBG 3 RBG 4 RBG 5 RBG 10 RBG 11 RBG 12 RBG 13

……

frequency


In resource allocations of Type 1, individual PRBs can be addressed (but only within a subset of the PRBs available). The bitmap used is slightly smaller than for Type 0, since some bits are used to indicate the subset of the RBG which is addressed, and a shift in the position of the bitmap. The total number of bits (including these additional flags) is the same as for Type 0. An example for the case of RB

DLN = 25, NRBG = 11 and P = 2 is shown in Figure 15. One bit is used for subset selection and another bit to indicate the shift.

The motivation for providing this method of resource allocation is flexibility in spreading the resources across the frequency domain to exploit frequency diversity.



Figure 15 PRBs addressed by a bitmap Type 1, each bit addressing a subset of a RBG, depending on a subset selection and shift value

PRB1

PRB3

PRB5

PRB7

PRB9

PRB19

PRB21

RBG 1 RBG 2 RBG 3 RBG 4 RBG 5 RBG 10 RBG 11

……

Subset Selection = 0, Shift = 0

PRB2

PRB4

PRB6

PRB8

PRB20

PRB22

PRB10


……


PRB5

PRB7

PRB9

PRB19

PRB21

PRB23

PRB25


……


PRB4

PRB6

PRB8

PRB20

PRB22

PRB24

PRB10


……



In resource allocations of Type 2, the resource allocation information indicates to a scheduled UE either:

• a set of contiguously allocated PRBs, or

• a distributed allocation comprising multiple non-consecutive PRBs

The distinction between the two allocation methods is made by a 1-bit flag in the resource allocation message. PRB allocations may vary from a single PRB up to a maximum number of PRBs spanning the system bandwidth.

For PDCCH DCI format 1A, 1B or 1D, a Type 2 resource allocation field consists of a Resource Indication Value (RIV) corresponding to a starting resource block (RBSTART) and a length in terms of contiguously-allocated resource blocks (LCRBs). The resource indication value is defined by:

if 2/)1( DLRBCRBs NL ≤− then

startCRBsDLRB RBLNRIV +−= )1(

else

)1()1( startDLRBCRBs

DLRB

DLRB RBNLNNRIV −−++−=

where



CRBsL ≥ 1 and shall not exceed startDL

VRB RBN − .

For PDCCH DCI format 1C, a type 2 resource block assignment field consists of a

resource indication value (RIV) corresponding to a starting resource block ( startRB = 0 , stepRBN ,

stepRB2N ,…, step

RBstepRB

DLVRB )1/( NNN − ) and a length in terms of virtually contiguously

allocated resource blocks ( CRBsL =stepRBN ,

stepRB2N ,…, step

RBstepRB

DLVRB / NNN ⋅ ). The resource

indication value is defined by

if 2/)1( DLVRBCRBs NL ′≤−′

then

startCRBsDL

VRB BRLNRIV ′+−′′= )1(

else

)1()1( startDL

VRBCRBsDL

VRBDL

VRB BRNLNNRIV ′−−′++′−′′=

where

stepRBCRBsCRBs NLL /=′ ,

stepRBstartstart NRBBR /=′

and stepRB

DLVRB

DLVRB NNN /=′

.

Here CRBsL′ ≥ 1 and shall not exceed startDL

VRB BRN ′−′ .

Parameter related to resource allocation type 2 is as follows. Please refer to section 4.4.2.3 for detailed information.

1) Number of PRB that VRB is mapped into: This parameter configures the RB number which is used to map from VRB to PRB.

3.4 PUSCH Frequency Hopping Different techniques that provide uplink diversity can be used in cases where channel dependent scheduling is not suitable. Hopping in frequency can be performed on PUSCH. Thus frequency hopping in the uplink can be called PUSCH frequency hopping. 3GPP specifies two types of frequency hopping for the LTE uplink, Type 1 PUSCH hopping and Type 2 PUSCH hopping.

As mentioned in 2.1.4, DCI format 0 is used to transport scheduling information for the uplink. It has a 1 bit hopping flag to indicate whether PUSCH frequency hopping is enabled or not. Thus a UE with a scheduling grant performs frequency hopping if this hopping flag is set to 1. Depending on the system bandwidth, 1 or 2 bits are excluded from the resource allocation field in DCI format 0 as shown in Table 9in case of hopping.

Depending on the information in the hopping bits (DCI format 0 as shown in Table 4), a frequency hopping user performs either Type 1 or Type 2 PUSCH hopping. In each type



of PUSCH hopping, there is a possibility to hop in frequency between subframes, inter-subframe hopping, or within a subframe, intra-subframe hopping depending on a single bit information provided from higher layers.

Parameter related to PUSCH frequency hopping is as follows. Please refer to section 4.3.2.1 for detailed information.

1) PUSCH frequency hopping indicator: This parameter indicates whether PUSCH frequency hopping is enabled.

3.4.1 Type 1 PUSCH Hopping

In the first type of hopping, the hopping information is provided in the scheduling grant. Thus it can be called “hopping based on explicit hopping information in the scheduling grant”. To keep the single carrier property of the LTE uplink, users are allocated on contiguously allocated resource blocks, LCRBs, starting from the lowest index physical resource block (PRB) in each transmission slot.

• The first PRB (lowest index PRB) in the first slot of subframe number i, )(1 inSPRB , is

given by 错误！未找到引用源。:

2/~)(~)( HORB

11 Ninin SPRB

SPRB +=

where

STARTSPRB RBin =)(1

, and STARTRB is obtained from the uplink scheduling grant.

• The lowest index PRB ( )(inPRB ) of the 2nd slot RA in subframe i is defined as

2/~)(~)( HORBNinin PRBPRB +=

where

)(~ inPRB depends on the information in the hopping bits as shown in Table 9.

For instance, for a system bandwidth less than 10 MHz (50 RBs), if the hopping bit is set to 0, Type 1 PUSCH hopping will be performed in the second slot with a hop of half the hopping bandwidth. However if the hopping bit is set to 1, Type 2 PUSCH hopping will be carried out. Similarly, for system bandwidth of 10 MHz and above (50-110 RBs), hopping will be performed in the second slot with an offset of 1/2, 1/4, or -1/4 as shown in Table 9.

Table 9 LTE uplink SC-FDMA parameters for selected carrier bandwidths

System BW ULRBN Number of

Hopping bits Information in hopping bits )(~ inPRB

6 – 49 1 0 PUSCH

RBSPRB

PUSCHRB NinN mod)(~2/ 1

+

,

1 Type 2 PUSCH Hopping



50 – 110 2

00 PUSCHRB

SPRB


+

01 PUSCHRB

SPRB


+−

10 PUSCHRB

SPRB


+

11 Type 2 PUSCH Hopping

The hopping within a subframe, intra-subframe hopping, described above is repeated for the other subframes. Thus this type of hopping can be referred as intra and inter-subframe hopping.

If the hopping is inter-subframe only, the resource allocation for the first and second slot is applied to even CURRENT_TX_NB and odd CURRENT_TX_NB, respectively. CURRENT_TX_NB is “a state variable, which indicates the number of transmissions that have taken place for the MAC PDU currently in the buffer”.

Practical Demonstration of Type 1 PUSCH Hopping:

Figure 16 demonstrates Type 1 PUSCH hopping for a system bandwidth of 10 MHz (50 RBs) with the hopping information bits set to “1 0”. Six RBs have been allocated for control signaling, PUCCH, 3 at each end. Thus the hopping bandwidth will be 44 RBs. Based on Table 9, the offset in the second slot with respect to the lowest index PRB in slot 0, will be half the hopping bandwidth. UE1 has been allocated on the first two PUSCH RBs in slot 0 with the lowest index PRB being 3. It hops by an offset of 22 RBs, i.e., half the hopping bandwidth, and is mapped to the 25th and 26th RBs. In a similar fashion all the UEs perform hopping as shown in the figure.

Figure 16 Type 1 intra-subframe PUSCH hopping

Subframe i Slot 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49

0

1

PUCCH UE 1 scheduled UE 2 scheduled UE 3 scheduled UE 4 scheduled

0

RB

UE 1

UE 1

UE 2

UE 2

UE 3

UE 3

UE 4

UE 4

Hence the period of the hopping pattern is one subframe in case of intra and inter-subframe hopping and two subframes in case of inter-subframe only hopping.

3.4.2 Type 2 PUSCH Hopping

In Type 2 PUSCH hopping, the hopping bandwidth is virtually divided into sub-bands of equal width. Each sub-band constitutes a number of contiguous resource blocks. In Figure 17, for a system bandwidth of 50 RBs, the PUSCH bandwidth is divided into 4 sub-bands with 11 RBs in each sub-band. As in the example for Type 1 PUSCH hopping, 6 RBs were allocated for PUCCH



Figure 17 Hopping bandwidth is divided into equal sub-bands to perform sub-band based hopping

Subframe i Slot 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 490

1

RB

0one sub-band

In addition to hopping, the UEs can also perform mirroring as a function of the slot number. While mirroring, the resource allocation starts from the right edge of the sub-band where a UE is allocated. The hopping and mirroring patterns are cell-specific. Thus Type 2 PUSCH hopping can also be referred to as “sub-band based hopping according to cell-specific hopping/mirroring patterns”.

Practical Demonstration of Type 2 PUSCH Hopping:

An illustration of Type 2 PUSCH hopping is presented in Figure 18 for a system bandwidth of 10MHz. To enable sub-band based hopping, the overall PUSCH bandwidth is divided in to 4 sub-bands. A similar configuration is used for PUCCH as in the demonstration for Type 1.

Figure 18 Type 2 intra and inter-subframe PUSCH hopping

Subframe i Slot 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 4901

PUCCH UE 1 scheduled UE 2 scheduled UE 3 scheduled UE 4 scheduled

0UE 1 UE 4

UE 2

RB

UE 3UE 4UE 3 UE 1

UE 2

For this particular example, a cell-id = 3 is used to initialize the scrambling sequence. For the sake of demonstration, 4 UEs are scheduled continuously for 4 subframes. UE1 occupies the RBs 9~13, however the resource allocation starts from RB number 13 as shown by the black arrow. This is because fm(0) = 1 indicating that mirroring is used in slot 0. In the second slot, UE1 hops to the third sub-band and transmits on the RBs 25~29. Since mirroring is not used in this slot, the resource block allocation starts from the left edge of the sub-band. Similarly, all the other UEs perform hopping and mirroring as shown in the above figure.

3.4.3 Comparison of Type 1 and Type 2 PUSCH Hopping

3.4.3.1 Diversity

In Type 1 PUSCH hopping, there are three different hopping options with a period of only 1 subframe in case of intra and inter-subframe hopping or 2 subframes in case of inter-subframe hopping mode as explained in 3.4.1 above. A UE may perform hopping in the second slot with an offset of 1/2, 1/4, or -1/4 of the PUSCH bandwidth with respect to the lowest index PRB in the first slot.

However, with Type 2 PUSCH hopping there is a possibility to perform both hopping and mirroring with different patterns with a period of one frame or 10 subframes. This gives more frequency diversity to mitigate the effects of frequency selective fading.

In addition, the hopping and mirroring patterns are cell–specific in hopping Type 2. This gives a possibility to mitigate the effects of inter-cell interference by averaging the interference over a number of users.



3.4.3.2 Limitations on the scheduler

As discussed in 3.4.1 above, 1 or 2 bits are used to provide hopping information which puts a limitation on the number of contiguous resource blocks that can be allocated to a single user. For instance for a system bandwidth of 5 MHz (= 25 RBs), with PUSCH hopping Type 1 and Type 2 with one sub-band (Nsb = 1), the maximum number of contiguous RBs that can be allocated to a single user is 10. However, for Type 2 with 4 sub-bands, the length of contiguous RBs drops to 5 RBs. Hence, as the number of sub-bands increases, the length of contiguous RBs that can be allocated for a single user becomes shorter.

In addition, a UE cannot be allocated on RBs that are in different sub-bands even though there are free RBs. Hence Type 2 PUSCH hopping puts more limitation on the scheduler. According to 3GPP’s specification for PUSCH configuration, the number of sub-bands can be from 1 to 4 (错误！未找到引用源。, PUSCH-config).

3.5 PRACH Format 0 ~ 3 Similarly to WCDMA, the LTE PRACH preamble consists of a complex sequence. However, it differs from the WCDMA preamble in that it is also an OFDM symbol, built with a CP, thus allowing for an efficient frequency-domain receiver at the eNodeB. As shown in Figure 19, the end of the sequence is appended at the start of the preamble, thus allowing a periodic correlation at the PRACH receiver

The UE aligns the start of the random access preamble with the start of the corresponding uplink subframe at the UE assuming a timing advance of zero, and the preamble length is shorter than the PRACH slot in order to provide room for a Guard Time (GT) to absorb the propagation delay. Figure 19 shows two preambles at the eNodeB received with different timings depending on the propagation delay: as for a conventional OFDM symbol, a single observation interval can be used regardless of the UE’s delay, within which periodic correlation is possible.

3.5.1 PRACH Formats

Four Random Access (RA) preamble formats are defined for Frequency Division Duplex (FDD) operation. Each format is defined by the durations of the sequence and its CP, as listed in Table 10.



Figure 19 PRACH preamble received at the eNodeB

CP Sequence

PRACH preamble GT

CP Sequence

Observation interval

PRACH slot duration

UE close to the eNB

UE at cell edge

Table 10 Random access preamble formats

Preamble format TCP (us) TSEQ (us) Typical usage

0 103.13 800 Normal 1ms RA burst with 800us preamble sequence, for small-medium cells (up to ~14km)

1 648.38 800 2ms RA burst with 800us preamble sequence, for large cells (up to ~77km) without a link budget problem

2 203.13 1600 2ms RA burst with 1600us preamble sequence, for medium cells (up to ~29km)

3 684.38 1600 3ms RA burst with 1600us preamble sequence, for very large cells (up to ~100km)

3.5.2 CP and GT Duration

For formats 0 and 2, the CP is dimensioned to maximize the coverage, given a maximum delay spread d:

TCP = (1000 − 800)/2 + d/2 us,

with d ≈ 5.2 μs (corresponding to the longest normal CP of a PUSCH SC-FDMA symbol). The maximum delay spread is used as a guard period at the end of CP, thus providing protection against multipath interference even for the cell-edge UEs.

In addition, for a cell-edge UE, the delay spread energy at the end of the preamble is replicated at the end of the CP (see Figure 20) and is therefore within the observation interval. Consequently, there is no need to include the maximum delay spread in the GT dimensioning. Hence, instead of locating the sequence in the centre of the PRACH slot, it is shifted later by half the maximum delay spread, allowing the maximum Round-Trip Delay (RTD) to be increased by the same amount. Note that, as for a regular OFDM symbol, the residual delay spread at the end of the preamble from a cell-edge UE spills over into the next subframe, but this is taken care of by the CP at the start of the next subframe to avoid any inter-symbol interference.



Figure 20 PRACH preamble received at the eNodeB

CP

Max RTD

UE close to the eNB

UE at cell edge

Max delay spread

TCP Observation interval

CP

Max delay spread

GT = max RTD

PRACH time slot

For formats 1 and 3, the CP is dimensioned to address the maximum cell range in LTE, 100 km, with a maximum delay spread of d ≈ 16.67 μs. In practice, format 1 is expected to be used with a 3-subframe PRACH slot; the available GT in 2 subframes can only address a 77 km cell range. It was chosen to use the same CP length for both format 1 and format 3 for implementation simplicity. Of course, handling larger cell sizes than 100km with suboptimal CP dimensioning is still possible and is left to implementation.

Table 11 shows the resulting cell radius and delay spread ranges associated with the four PRACH preamble formats. The CP lengths are designed to be an integer multiple of the assumed system sampling period for LTE, TS = 1/30.72μs.

Table 11 Cell radius of PRACH preamble formats

Preamble format

Number of allocated subframes

CP duration GT duration Max. delay spread (μs)

Max. cell radius (km) In μs As multiple

of TS In μs As multiple of TS

0 1 103.13 3168 96.88 2976 6.25 14.53 1 2 684.38 21024 515.63 15840 16.67 77.34 2 2 203.13 6240 196.88 6048 6.25 29.53 3 3 684.38 21024 715.63 21984 16.67 100.16

These are also illustrated in Figure 21.



Figure 21 PRACH preamble formats and cell size dimensioning

1 subframe

Max. cell size (2*radius)



Max delay spread


Preamble format

0

1

2

3

CP sequence Guard time

3.6 Uplink: QPSK/16QAM, Downlink: QPSK/16QAM/64QAM The downlink/uplink data modulation transforms a block of scrambled bits to a corresponding block of complex modulation symbols Figure 22. The set of modulation schemes supported for the LTE downlink/uplink includes QPSK, 16QAM and 64QAM, corresponding to two, four, and six bits per modulation symbol.

Figure 22 Data modulation (QPSK: L = 2, 16QAM: L = 4, 64QAM: L = 6)

M bits

Data modulator

M/L modulation symbols

All these modulation schemes are applicable in case of DL-SCH and UL-SCH transmission. For other transport channels, certain restrictions may apply. As an example, only QPSK modulation can be applied in case of BCH transmission.

3.7 Uplink: 64QAM 64QAM in uplink is related to UE capabilities because:

• Support for the highest data rates is key to the success of some applications, but generally requires large amounts of memory for data processing, which increases the cost of the UE;

LTE system has been designed to support five categories of UE, ranging from relatively low-cost terminals with similar capabilities to UMTS HSPA, up to very high-capability terminals which exploit the LTE technology to the maximum extent possible and exceed the peak data rate targets.



The capabilities of the five categories are summarized in Table 12.

Table 12 Categories of LTE UE

UE category 1 2 3 4 5

Maximum downlink data rate (Mbps) 10 50 100 150 300 Maximum uplink data rate (Mbps) 5 25 50 50 75 Number of downlink MIMO streams supported 1 2 2 2 4 Support of 64QAM modulation in downlink Yes Yes Yes Yes Yes Support of 64QAM modulation in uplink No No No No Yes

3.8 TX Diversity When employed for user data, one or, at most two transport blocks can be transmitted per UE per subframe, depending on the transmission mode selected for the PDSCH for each UE. The transmission mode configures the multi-antenna technique usually applied错误！未找到引用源。:

Transmission Mode 1: Transmission from a single eNodeB antenna port;

Transmission Mode 2: Transmit diversity;

Transmission Mode 3: Open-loop spatial multiplexing;

Transmission Mode 4: Closed-loop spatial multiplexing;

Transmission Mode 5: Multi-user MIMO;

Transmission Mode 6: Closed-loop rank-1 precoding;

Transmission Mode 7: Transmission using UE-specific reference signals.

In LTE, transmit diversity is only defined for 2 and 4 transmit antennas, and one data stream, referred to in LTE as one codeword since one transport block CRC is used per data stream. To maximize diversity gain the antennas typically need to be uncorrelated, so they need to be well separated relative to the wavelength or have different polarization. Transmit diversity still has its value in a number of scenarios, including low SNR, low mobility (no time diversity), or for applications with low delay tolerance. Diversity schemes are also desirable for channels for which no uplink feedback signaling is available (e.g. MBMS, PBCH).

In LTE the MIMO scheme is independently assigned for the control channels and the data channels, and is also assigned independently per UE in the case of PDSCH.

3.8.1 Space-Frequency Block Codes (SFBCs)

If a physical channel in LTE is configured for transmit diversity operation using two eNodeB antennas, pure SFBC is used. SFBC is a frequency-domain version of the well-known Space-Time Block Codes (STBCs), also known as Alamouti codes. This family of



codes is designed so that the transmitted diversity streams are orthogonal and achieve the optimal SNR with a linear receiver. Such orthogonal codes only exist for the case of two transmit antennas. STBC is used in UMTS, but in LTE the number of available OFDM symbols in a subframe is often odd while STBC operates on pairs of adjacent symbols in the time domain. The application of STBC is therefore not straightforward for LTE, while the multiple subcarriers of OFDM lend themselves well to the application of SFBC.

For SFBC transmission in LTE, the symbols transmitted from the two eNodeB antenna ports on each pair of adjacent subcarriers are defined as follows:

−

=

*1

*2

21)1()1(

)0()0(

)2()1()2()1(

xxxx

yyyy

where

y(p)(k) denotes the symbols transmitted from antenna port p on the kth subcarrier.

Since no orthogonal codes exist for antenna configurations beyond 2*2, SFBC has to be modified in order to apply it to the case of 4 transmit antennas.

3.8.2 Frequency Switched Transmit Diversity (FSTD) and its Combination with SFBC

General FSTD schemes transmit symbols from each antenna on a different set of subcarriers. For example, an FSTD transmission from 4 transmit antennas on four subcarriers might appear as follows:

=

4

3

2

1

)3()3()3()3(

)2()2()2()2(

)1()1()1()1(

)0()0()0()0(

000000000000

)4()3()2()1()4()3()2()1()4()3()2()1()4()3()2()1(

xx

xx

yyyyyyyyyyyyyyyy

where

as previously, y(p)(k) denotes the symbols transmitted from antenna port p on the kth subcarrier.

In LTE, FSTD is only used in combination with SFBC for the case of 4 transmit antennas, in order to provide a suitable transmit diversity scheme where no orthogonal rate-1 block codes exists. The LTE scheme is in fact a combination of two 2*2 SFBC schemes mapped to independent subcarriers as follows:

−−

=

*3

*4

*1

*2

43

21

)3()3()3()3(

)2()2()2()2(

)1()1()1()1(

)0()0()0()0(

0000

0000

)4()3()2()1()4()3()2()1()4()3()2()1()4()3()2()1(

xxxx

xxxx

yyyyyyyyyyyyyyyy



Note that mapping of symbols to antenna ports is different in the 4 transmit-antenna case compared to the 2 transmit-antenna SFBC scheme. This is because the RS density on the third and fourth antenna ports is half that of the first and second antenna ports, and hence the channel estimation accuracy may be lower on the third and fourth antenna ports. Thus, this design of the transmit diversity scheme avoids concentrating the channel estimation losses in just one of the SFBC codes, resulting in a slight coding gain.

3.9 Open-loop Spatial Multiplexing

3.9.1 Introduction

Three basic terms used to describe spatial multiplexing in LTE are as follows:

• Spatial layer: A layer can be described as a mapping of symbols onto the transmit antenna ports. Each layer is identified by a (precoding) vector of size equal to the number of transmit antenna ports and can be associated with a radiation pattern.

• Rank: the number of layers transmitted.

• Codeword: an independently encoded data block, corresponding to a single Transport Block (TB) delivered from the Medium Access Control (MAC) layer in the transmitter to the physical layer, and protected with a CRC.

The baseband signal representing a downlink physical channel is defined in terms of the following steps as shown in Figure 23 错误！未找到引用源。.

• scrambling of coded bits in each of the code words to be transmitted on a physical channel;

• modulation of scrambled bits to generate complex-valued modulation symbols;

• mapping of the complex-valued modulation symbols onto one or several transmission layers;

• precoding of the complex-valued modulation symbols on each layer for transmission on the antenna ports;

• mapping of complex-valued modulation symbols for each antenna port to resource elements;

• generation of complex-valued time-domain OFDM signal for each antenna port;



Figure 23 Overview of physical channel processing with MIMO

Scrambling Modulation mapper

Layermapper Precoding

Resource element mapper

OFDM signal generation

Resource element mapper

OFDM signal generationScrambling Modulation

mapper

layers antenna portscode words

For ranks greater than 1, two codewords can be transmitted. Note that the number of codewords is always less than or equal to the number of layers, which in turn is always less than or equal to the number of antenna ports.

In principle, a SU-MIMO spatial multiplexing scheme can either use a single codeword mapped to all the available layers, or multiple codewords each mapped to one or more different layers.

• The main benefit of using only one codeword is a reduction in the amount of control signalling required, both for CQI reporting, where only a single value would be needed for all layers, and for HARQ ACK/NACK feedback, where only one ACK/NACK would have to be signalled per subframe per UE.

• At the opposite extreme, a separate codeword could be mapped to each of the layers. For LTE, at most two codewords are used, even if four layers are transmitted. The codeword-to-layer mapping is static, since only minimal gains were shown for a dynamic mapping method. The mappings are shown in Table 13. Note that in LTE all RBs belonging to the same codeword use the same MCS, even if a codeword is mapped to multiple layers.

Table 13 Codeword-to-layer mapping

Codeword 1 Codeword 2 Rank 1 Layer 1 Rank 2 Layer 1 Layer 2 Rank 3 Layer 1 Layer 2 and Layer 3 Rank 4 Layer 1 and Layer 2 Layer 3 and Layer 4

The PDSCH transmission modes for open-loop spatial multiplexing and closed-loop spatial multiplexing use precoding from a defined ‘codebook’ to form the transmitted layers. Each codebook consists of a set of predefined precoding matrices, with the size of the set being a trade-off between the number of signalling bits required to indicate a particular matrix in the codebook and the suitability of the resulting transmitted beam direction.

3.9.2 Cyclic Delay Diversity (CDD)

In the case of open-loop spatial multiplexing, the feedback from the UE indicates only the rank of the channel, and not a preferred precoding matrix. In this mode, if the rank used for PDSCH transmission is greater than 1 (i.e. more than one layer is transmitted), Cyclic Delay Diversity (CDD) is used 错误！未找到引用源。. CDD involves transmitting the same set of OFDM symbols on the same set of OFDM subcarriers from multiple transmit



antennas, with a different delay on each antenna. The delay is applied before the CP is added, thereby guaranteeing that the delay is cyclic over the Fast Fourier Transform (FFT) size. This gives CDD its name.

Adding a time delay is identical to applying a phase shift in the frequency domain. As the same time delay is applied to all subcarriers, the phase shift will increase linearly across the subcarriers with increasing subcarrier frequency. Each subcarrier will therefore experience a different beamforming pattern as the non-delayed subcarrier from one antenna interferes constructively or destructively with the delayed version from another antenna. The diversity effect of CDD therefore arises from the fact that different subcarriers will pick out different spatial paths in the propagation channel, thus increasing the frequency-selectivity of the channel. The channel coding, which is applied to a whole transport block across the subcarriers, ensures that the whole transport block benefits from the diversity of spatial paths.

Although this approach does not optimally exploit the channel in the way that ideal precoding would (by matching the precoding to the eigenvectors of the channel), it does help to ensure that any destructive fading is constrained to individual subcarriers rather than affecting a whole transport block. This can be particularly beneficial if the channel information at the transmitter is unreliable, for example due to the feedback being limited or the UE velocity being high. The general principle of CDD is shown in Figure 24.

Figure 24 Principle of Cyclic Delay Diversity

Delay CP addition and transmission

CP addition and transmission…

...…

...

…...

…...

…...

…...

…...

Subcarrier 1

Subcarrier 2

Subcarrier K

OFDM subcarriers

3.10 Closed-loop Spatial Multiplexing In the case of closed-loop spatial multiplexing, a UE feeds back to the eNodeB the most desirable entry from a predefined codebook. The preferred precoder is the matrix which would maximize the capacity based on the receiver capabilities. In a single-cell, interference-free environment the UE will typically indicate the precoder that would result in transmission with an effective SNR following most closely the largest singular values of its estimated channel matrix.

As an example, the set of defined precoder matrices for the case of two antenna ports is shown in Table 14.

Table 14 Precoder matrices in case of two antenna ports

One layer

11

21

−11

21

j1

21

− j1

21



Two Layers

−1111

21

− jj11

21

To assist the eNodeB in selecting a suitable precoder matrix for transmission, UE may report: Rank Indicatior (RI), Precoding Matrix Indicator (PMI) plus Channel Quality Indicator (CQI).

• RI: providing information about the channel rank or, expressed differently, the number of layers that should, preferably, be used for downlink transmission to the UE. RI only needs to be reported by terminals that are configured to be in one of the spatial-multiplexing transmission modes.

• PMI: providing a precoder matrix that should, preferably, be used for the downlink transmission. The reported precoder matrix should be determined assuming the number of layers indicated by the RI. PMI is only reported if the UE is configured to be in closed-loop spatial-multiplexing mode. In case of open-loop spatial multiplexing, the eNodeB instead selects the precoder matrix to use for transmission according to a pre-defined rule. The precoder recommendation may be frequency-selective, implying that the terminal may recommend different precoders for different parts of the downlink spectrum

• CQI: representing the recommended modulation scheme and coding rate that should, preferably, be used for the downlink transmission. The CQI points into a table that consists of a set of pre-defined modulation-scheme/coding-rate combinations.

With regards to the precoder-related recommendations, the eNodeB has two choices:

• The eNodeB may follow the UE recommendation, in which case it only has to confirm (a one bit indicator in the downlink scheduling assignment) that the precoder configuration recommended by the terminal is used for the downlink transmission. On receiving such a confirmation, the UE will use its recommended configuration when demodulating and decoding the corresponding DL-SCH transmission.

• The eNodeB may select a different precoder configuration, information about which then needs to be explicitly included in the downlink scheduling assignment. The UE then uses this configuration when demodulating and decoding the DL-SCH. To reduce the amount of downlink signaling, only a single precoding matrix can be signaled in the scheduling assignment.

3.11 Closed-loop Spatial Multiplexing (Rank = 1) Rank-1 means only 1 codeword transmitted as mentioned in Table 13. A rank-1 transmission can happen for the case of one, two or four antenna ports while for rank-2 transmission, the number of antenna ports needs to be at least 2.



In case of rank-1 transmission, the complex-valued modulation symbols d(0)(i) from a single codeword are mapped to a single layer as shown in Figure 25.

Figure 25 Rank-1 transmission

d(0)(0) d(0)(1) d(0)(2) …... Precoding

Codeword 1

Layer 1

…... Antenna ports

(1, 2 or 4)

Also the number of modulation symbols per layer is equal to the number of modulation symbols per codeword. For rank-1 transmission, the layer mapping operation is transparent with codeword modulation symbols simply mapped to a single layer.

3.12 Uplink RX Diversity with IRC The Interference Rejection Combining (IRC) receiver calculates and applies a set of antenna weights in the receiver to maximise the SINR of the signal post-combining, taking into account the instantaneous direction of arrival of the wanted and interfering signals. This is in contrast to a Maximum Ratio Combining (MRC) receiver which does not consider the spatial characteristics of the interference when calculating the antenna weights.

3.13 Uplink MU-MIMO Uplink MU-MIMO consists of multiple UEs transmitting on the same set of RBs, each using a single transmit antenna. From the point of view of an individual UE, such a mode of operation is hardly visible, being predominantly a matter for the eNodeB to handle in terms of scheduling and uplink reception.

However, in order to support uplink MU-MIMO, the eNodeB specifically provides orthogonal DMRS using different cyclic time shifts to enable the eNodeB to derive independent channel estimates for the uplink from each UE.

A cell can assign up to eight different cyclic time shifts using the 3-bit PUSCH cyclic time shift offset on the uplink scheduling grant. As a maximum of eight cyclic time shifts can be assigned, SDMA of up to eight UEs can be supported in a cell. SDMA between cells (i.e. uplink inter-cell cooperation) is supported in LTE by assigning the same base sequence groups and/or RS hopping patterns to the different cells.

3.14 PUCCH Blanking For adjacent UL/DL co-existence, in order to meet regulatory requirements from the edge of an operating band/channel, it is normal to specify a guard band and an



associated spurious emission limit. The guard / protection band is usually specified as a fixed spectrum block and used to address UE to UE co-existence as well as Base station to Base station co-existence. This issue of co-existence happens when allocating a high power transmission at the channel edge nearest a victim or protected band.

In particular, it notes for these deployment scenarios the PUCCH would be transmitting at maximum power and would be located at the channel edge. Reducing the power of the PUCCH transmissions to meet the required emission target would have a severe impact on coverage and system performance and is therefore not a realistic solution.

In the general case each physical uplink control channel (PUCCH) consists of a single physical resource block (PRB) pair comprising one PRB per slot located near each band edge. The ACK/NACK, SR, and CQI transmissions on PUCCH use up to +23dBm power levels (for Class 3 UE’s) which can contribute to spurious emissions that impact adjacent carriers with guard bands less than the larger carrier bandwidth. Such configurations are unlikely to meet the spurious emission target for UL/DL co-existence.

PUCCH blanking is a method that the number of PRBs allocated for PUCCH is over-

provisioned (i.e. )2(

RBN or nRB-CQI is larger than nominally required) and then only the PUCCH PRBs farthest from each band edge (i.e., offset from either band-edge) are actually assigned for ACK/NACK, SR, and CQI/PMI/RI transmissions. Thus it appears as if the active PUCCH locations have been shifted away from the band edge by the same (symmetrical) frequency offset on each edge as shown in the following figure.

Figure 26 PUCCH blanking (over-provisioned PUCCH)

The resulting over-provisioning on both the lower band-edge and upper band-edge results in PUSCH peak rate loss which can be quite large especially when over-provisioning is not needed on one of the band edges. Also, due to the unnecessary symmetric PUCCH relocation, the PUCCH frequency diversity is reduced.

m=14 m=12 m=10 m=8

m=15 m=13 m=11 m=9

0 1 2 3 4 43424140

1ms

Slot 1

Slot 0

PUCCH1/1a/1b

Allocated PUCCH2/2a/2b

Frequency(PRB Index)

m=6 m=4

m=7 m=5

m=2 m=0

m=3 m=1

m=5 m=7 m=9 m=11 m=13 m=15

m=4 m=6 m=8 m=10 m=12 m=14

m=1 m=3

m=0 m=2

49484746454439381110987

1 PRB

2

)2(RBN

2

)2(RBN

5 6

Over-provisioned PUCCH region

2

PUCCHRBN

2

PUCCHRBN12)2( =RBN # of RBs for PUCCH format 2/2a/2b

16=PUCCHRBN # of PUCCH RBs

PUCCH1/1a/1b

AllocatedPUCCH2/2a/2b



4 Configuration of Parameters

4.1 Parameters related to the serving cell

4.1.1 Parameter list related to the serving cell Abbreviated name Parameter name

dwDlCenterFreq Downlink center carrier frequency dwUlCenterFreq Uplink center carrier frequency byFreqBandInd Band indicator for DL and UL frequency wPhyCellId Physical cell id byDlAntCapacity Capacity of downlink antenna in a cell byUlAntCapacity Capacity of uplink antenna in a cell byPhyChCPSel CP selection for physical channel byTransDivInd Indicator of cell transmission diversity used byOpenLpSpMulInd Indicator of cell open-loop spatial multiplexing used byClsLpSpMulInd Indicator of cell closed-loop spatial multiplexing

used byDlSysBandWidth Downlink system bandwidth byUlSysBandWidth Uplink system bandwidth byComPhChTrDivInd Transmission diversity indicator for common

channel (PBCH/PCFICH/PHICH/PDCCH) wCellRadius UL 64QAM demodulation support indicator byUl64QamDemSpInd Cell radius byMUMIMOSupport Switch for whether MU-MIMO is supported byMIMOTestMode Switch for whether test mode for MIMO is

supported byCFI CFI selection

4.1.2 Parameter configuration related to the serving cell

4.1.2.1 Downlink Center Carrier Frequency

Parameter name Downlink Center Carrier frequency

Abbrevatied name dwDlCenterFreq

Description

This parameter indicates the downlink E-UTRA Absolute Radio Frequency Channel Number (EARFCN). F_DL is center carrier frequency, F_DL_low is dl lowest carrier frequency, N_DL is DlEARFCN, N_Offs-Dl is carrier frequency offset indicated by band indicator.

Range and Step

It depends on the band indicator for DL and UL frequency. (1:2110-2170, 2:1930-1990, 3:1805-1880, 4:2110-2155, 5:869-894, 7:2620-2690, 8:925-960, 9:1844.9-1879.9, 10:2110-2170, 11:1475.9-1500.9, 12:728-746, 13:746-756, 14:758-768, 17:734-746, 18:860-875, 19:875-890, 20:791 -821, 21:1495.9-1510.9)MHz, step 0.1MHz.

Unit MHz



Parameter name Downlink Center Carrier frequency

Default Value N/A

4.1.2.2 Uplink Center Carrier Frequency

Parameter name Uplink Center Carrier Frequency

Abbrevatied name dwUlCenterFreq

Description

This parameter indicates the uplink E-UTRA Absolute Radio Frequency Channel Number (EARFCN). F_UL is center carrier frequency, F_UL_low is dl lowest carrier frequency, N_UL is DlEARFCN, N_Offs-Ul is carrier frequency offset indicated by band indicator.

Range and Step

It depends on the band indicator for DL and UL frequency. (1:2110-2170, 2:1930-1990, 3:1805-1880, 4:2110-2155, 5:869-894, 7:2620-2690, 8:925-960, 9:1844.9-1879.9, 10:2110-2170, 11:1475.9-1500.9, 12:728-746, 13:746-756, 14:758-768, 17:734-746, 18:860-875, 19:875-890, 20:791 -821, 21:1495.9-1510.9)MHz, step 0.1MHz.

Unit MHz

Default Value N/A

4.1.2.3 Band Indicator for DL and UL Frequency

Parameter name Band Indicator for DL and UL Frequency

Abbrevatied name byFreqBandInd

Description This parameter indicates the frequency band for downlink and uplink frequency. The downlink and uplink frequency is own to the same band.

Range and Step enum (1, 2, ..., 5, 7,…,14,17,…,21)

Unit N/A

Default Value N/A

4.1.2.4 Physical Cell ID

Parameter name Physical Cell ID

Abbrevatied name wPhyCellId

Description

This parameter is used to identify a cell. There are 504 unique physical-layer cell identities. The physical-layer cell identities are grouped into 168 unique physical-layer cell-identity groups, each group containing three unique identities. The grouping is such that each physical-layer cell identity is part of one and only one physical-layer cell-identity group. And the physical cell identities are space multiplexing and programmed by network programming people.

Range and Step int (0,1,…,503)

Unit N/A



Parameter name Physical Cell ID

Default Value N/A

4.1.2.5 Capacity of Downlink Antenna in a Cell

Parameter name Capacity of Downlink Antenna in a Cell

Abbrevatied name byDlAntCapacity

Description This parameter indicates the number of antenna port in a cell. Transmit diversity and spatial multiplexing will use multi-antenna port.

Range and Step enum (1, 2, 4)

Unit N/A

Default Value 2

4.1.2.6 Capacity of Uplink Antenna in a Cell

Parameter name Capacity of Uplink Antenna in a Cell

Abbrevatied name byUlAntCapacity

Description This parameter indicates the number of antenna port in a cell. Transmit diversity and spatial multiplexing will use multi-antenna port.

Range and Step enum (1, 2, 4)

Unit N/A

Default Value 2

4.1.2.7 CP Selection for Physical Channel

Parameter name CP Selection for Physical Channel

Abbrevatied name byPhyChCPSel

Description

This parameter indicates the cyclic preamble length used all pyhical channels except PRACH in non MBSFN subframe. If the cyclic preamble length is normal_cyclic_prefix, there are 7 OFDM symbol in a slot. If the cyclic preamble length is extended cyclic prefix, there are 6 OFDM symbol in a slot.

Range and Step enum (normal cyclic prefix, extended cyclic prefix)

Unit N/A

Default Value Normal cyclic prefix

4.1.2.8 Indicator of Cell Transmission Diversity Used

Parameter name Indicator of Cell Transmission Diversity Used

Abbrevatied name byTransDivInd



Parameter name Indicator of Cell Transmission Diversity Used

Description

This parameter indicates whether transmit diversity is used in the cell. Downlink common physical channel can use transmit diversity. PDSCH can use transmit diversity and open-loop spatial multiplexing and closed-loop spatial multiplexing. And each physical channel will configure transmission mode according to “Cell transmit diversity used indicator” and “Cell open-loop spatial multiplexing used indicator” and “Cell closed-loop spatial multiplexing used indicator”.

Range and Step Enum (not used, used)

Unit N/A

Default Value used

4.1.2.9 Indicator of Cell Open-loop Spatial Multiplexing Used

Parameter name Indicator of Cell Open-loop Spatial Multiplexing Used

Abbrevatied name byOpenLpSpMulInd

Description

This parameter indicates whether open-loop spatial multiplexing is used in the cell. Downlink common physical channel can use transmit diversity. PDSCH can use transmit diversity and open-loop spatial multiplexing and closed-loop spatial multiplexing. And each physical channel will configure transmission mode according to “Cell transmit diversity used indicator” and “Cell open-loop spatial multiplexing used indicator” and “Cell closed-loop spatial multiplexing used indicator”.


Unit N/A

Default Value Not used

4.1.2.10 Indicator of Cell Closed-loop Spatial Multiplexing Used

Parameter name Indicator of Cell Closed-loop Spatial Multiplexing Used

Abbrevatied name byClsLpSpMulInd

Description

This parameter indicates whether closed-loop spatial multiplexing is used in the cell. Downlink common physical channel can use transmit diversity. PDSCH can use transmit diversity and open-loop spatial multiplexing and closed-loop spatial multiplexing. And each physical channel will configure transmission mode according to “Cell transmit diversity used indicator” and “Cell open-loop spatial multiplexing used indicator” and “Cell closed-loop spatial multiplexing used indicator”.


Unit N/A

Default Value Not used



4.1.2.11 Downlink System Bandwidth

Parameter name Downlink System Bandwidth

Abbrevatied name byDlSysBandWidth

Description This parameter indicates the downlink system band width. It is used to determine the position of frequency for downlink physical channel and the resource allocation.

Range and Step (6, 15, 25, 50, 75, 100)

Unit RB

Default Value 100

4.1.2.12 Uplink System Bandwidth

Parameter name Uplink System Bandwidth

Abbrevatied name byUlSysBandWidth

Description This parameter indicates the uplink system band width. It is used to determine the position of frequency for uplink physical channel and the resource allocation.

Range and Step (6, 15, 25, 50, 75, 100)

Unit RB

Default Value 100

4.1.2.13 Transmission Diversity Indicator for Common Channel

Parameter name Transmission Diversity Indicator for Common channel (PBCH/ PCFICH/ PHICH/ PDCCH)

Abbrevatied name byComPhChTrDivInd

Description This parameter indicates whether transmit diversity for PBCH/ PCFICH/ PHICH/ PDCCH is active. If This parameter value is active, transmit diversity is used for PBCH/ PCFICH/ PHICH/ PDCCH.

Range and Step (inactive, active)

Unit N/A

Default Value inactive

4.1.2.14 Cell Radius

Parameter name Cell Radius

Abbrevatied name wCellRadius

Description This parameter indicates the size of cell radius.

Range and Step (0~65535)

Unit 10m

Default Value 100



4.1.2.15 UL 64QAM Demodulation Support Indicator

Parameter name UL 64QAM Demodulation Support Indicator

Abbrevatied name byUl64QamDemSpInd

Description This parameter indicates the uplink 64QAM capability of eNodeB. If it is “supported”, the uplink 64QAM demodulation is supported by the eNodeB.

Range and Step (supported, non-supported)

Unit N/A

Default Value Supported

4.1.2.16 Switch for Whether MU-MIMO is Supported

Parameter name Switch for Whether MU-MIMO is Supported

Abbrevatied name byMUMIMOSupport

Description This parameter is a switch to determine whether MU-MIMO is supported or not, 0: not support, 1:support

Range and Step (0:not support，1:support)

Unit N/A

Default Value Not Support

4.1.2.17 Switch for Whether Test Mode for MIMO is Supported

Parameter name Switch for Whether Test Mode for MIMO is Supported

Abbrevatied name byMIMOTestMode

Description This parameter is a switch to determine whether test mode for MIMO is supported or not, 0: Normal Mode, 1: Test Mode.

Range and Step (Normal Mode, Test Mode)

Unit N/A

Default Value Normal

4.1.2.18 CFI Selection

Parameter name CFI Selection

Abbrevatied name byCFI

Description This parameter indicates the CFI Value configured by high layer for cell. The CFI Value could be 1, 2, 3 or could be configured as auto-adjusted.

Range and Step (1, 2, 3, Dynamic)

Unit N/A

Default Value 2



4.2 Parameters related to baseband configuration

4.2.1 Parameter list related to baseband configuration Abbreviated name Parameter name

byDLEnabledAntNum Enabled Downlink Antenna Number byDLAnt1 Flag for Downlink Antenna No.1 in Use byDLAnt2 Flag for Downlink Antenna No.2 in Use byDLAnt3 Flag for Downlink Antenna No.3 in Use byDLAnt4 Flag for Downlink Antenna No.4 in Use byULEnabledAntNum Enabled Uplink Antenna Number byULAnt1 Flag for Uplink Antenna No.1 in Use byULAnt2 Flag for Uplink Antenna No.2 in Use byULAnt3 Flag for Uplink Antenna No.3 in Use byULAnt4 Flag for Uplink Antenna No.4 in Use

4.2.2 Parameter configuration related to baseband configuration

4.2.2.1 Enabled Downlink Antenna Number

Parameter name Enabled Downlink Antenna Number

Abbrevatied name byDLEnabledAntNum

Description This parameter is used to determine how many DL antennas can be enabled.

Range and Step (1, 2, 4)

Unit N/A

Default Value 1

4.2.2.2 Flag for Downlink Antenna No.1 in Use

Parameter name Flag for Downlink Antenna No.1 in Use

Abbrevatied name byDLAnt1

Description This parameter is a flag for downlink to determine whether antenna No.1 is in use or not.

Range and Step (NO, YES)

Unit N/A

Default Value YES









Unit N/A

Default Value YES






Unit N/A

Default Value YES






Unit N/A

Default Value YES

4.2.2.6 Enabled Uplink Antenna Number

Parameter name Enabled Uplink Antenna Number

Abbrevatied name byULEnabledAntNum

Description This parameter is used to determine how many UL antennas can be enabled.

Range and Step (1, 2, 4)

Unit N/A

Default Value 1

4.2.2.7 Flag for Uplink Antenna No.1 in Use

Parameter name Flag for Uplink Antenna No.1 in Use




Abbrevatied name byULAnt1

Description This parameter is a flag for uplink to determine whether antenna No.1 is in use or not.


Unit N/A

Default Value YES






Unit N/A

Default Value YES






Unit N/A

Default Value YES






Unit N/A

Default Value YES



4.3 Parameters related to physical uplink channel

4.3.1 Parameter list related to physical uplink channel Abbreviated name Parameter name

byPuschHopInd PUSCH Frequency Hopping Indicator byPucchBlankFlag PUCCH blanking byPucchBlankNum Numbers of Blanked RB of PUCCH

4.3.2 Parameter configuration related to physical uplink channel

4.3.2.1 PUSCH Frequency Hopping Indicator

Parameter name PUSCH Frequency Hopping Indicator

Abbrevatied name byPuschHopInd

Description This parameter indicates whether PUSCH frequency hopping is enabled.

Range and Step (False, True)

Unit N/A

Default Value False

4.3.2.2 PUCCH blanking

Parameter name PUCCH blanking

Abbrevatied name byPucchBlankFlag

Description This parameter indicates whether PUCCH blanking is enabled.

Range and Step (Close, Open)

Unit N/A

Default Value Close

4.3.2.3 Numbers of Blanked RB of PUCCH

Parameter name Numbers of Blanked RB of PUCCH

Abbrevatied name byPucchBlankNum

Description This parameter indicates the number of PUCCH RB is blanked.

Range and Step Int (0, 1, …, 98)

Unit N/A

Default Value 28



4.4 Parameters related to physical downlink channel

4.4.1 Parameter list related to physical downlink channel Abbreviated name Parameter name

byPuschHopInd Factor of PHICH Group byPhichDuration PHICH Duration byNd Number of PRB that VRB is Mapped Into

4.4.2 Parameter configuration related to physcial downlink channel

4.4.2.1 Factor of PHICH Group

Parameter name Factor of PHICH Group

Abbrevatied name byNg

Description

The Number of PHICH Group determines the number of PHICHs allocated for UEs in the cell. A PHICH group consists of multiple PHICH. If the preamble length is normal CP length, a PHICH group consists of 8 PHICH; If the preamble length is extened cp length, a PHICH group consists of 4 PHICH. The equation of PHICH group is N_PHICH^Group = ceil(N_h * (N_RB^DL / 8)) (for normal CP) or N_PHICH^Group = 2 * ceil(N_h * (N_RB^DL/ 8)) (for extended CP)

Range and Step (1/6, 1/2, 1, 2)

Unit N/A

Default Value 1

4.4.2.2 PHICH Duration

Parameter name PHICH Duration

Abbrevatied name byPhichDuration

Description The duration of PHICH determines how many OFDM symbols that PHICH will be mapped on, one OFDM symbol or three OFDM symbols.

Range and Step (Normal, Extended)

Unit N/A

Default Value Normal

4.4.2.3 Number of PRB that VRB is Mapped Into

Parameter name Number of PRB that VRB is Mapped Into

Abbrevatied name byNd

Description This parameter configures the RB number Which is used to map



Parameter name Number of PRB that VRB is Mapped Into

from VRB to PRB.

Range and Step (2, 3, 4, 5, 6)

Unit N/A

Default Value 3

5 Glossary 3GPP 3rd Generation Partnership Project

A

B

C

CDD Cyclic Delay Diversity

CFI Control Information Indicator

CM Cubic Matrix

CP Cyclic Prefix

CQI Channel Quality Indicator

D

DCI Downlink Control Information

DMRS DeModulation Reference Signal

DS-CDMA Direct Sequence – Code Division Multiple Access

E

F



FFT Fast Fourier Transform

FSTD Frequency Switched Transmit Diversity

G

GT Guard Time

H

I

IRC Interference Rejection Combining

ISI Inter Symbol Interference

L

LTE Long Term Evolution

M

MBMS Multimedia Broadcast and Multicast Services

MBSFN Multimedia Broadcast Single Frequency Network

MIB Master Information Block

MU-MIMO Multi-UE Multiple Input Multiple Output

N

O

OFDM Orthogonal Frequency Division Multiplexing

OFDMA Orthogonal Frequency Division Multiplexing Access

P



PAPR Peak-to-Average Power Ratio

PBCH Physical Broadcast Channel

PCFICH Physical Control Format Indicator Channel

PDCCH Physical Downlink Control Channel

PDSCH Physical Downlink Shared Channel

PHICH Physical Hybrid ARQ Indicator Channel

PMCH Physical Multicast Channel

PMI Precoding Matrix Indicator

PRACH Physical Random Access Channel

PRB Physical Resource Block

PSS Primary Synchronization Signal

PUCCH Physical Uplink Control Channel

PUSCH Physical Uplink Shared Channel

Q

R

RA Random Access

RACH Random Access Channel

RB Resource Block

RI Rank Indicator

RS Reference Signal

RTD Round Trip Delay

S

SC-FDMA Single Carrier – Frequency Division Multiplexing Access

SFBC Space Frequency Block Code

SR Scheduling Request



SRS Sounding Reference Signal

SSS Secondary Synchronization Signal

STBC Space Time Block Code

T

TB Transport Block

TDMA Time Division Multiple Access

TPC Transmit Power Control

U

UL-SCH Uplink Shared Channel

V

W

X

Y

Z

zte lte fdd physical layer overview feature description

Documents

uplink physical channels

physical signals

downlink physical channels

resource allocation

pusch frequency hopping

uplink parts

proprietary information

uplink rx diversity