doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 1 IEEE WRAN Merger Framework IEEE P Wireless RANs Date: Authors: Notice: This document has been prepared to assist IEEE It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEEs name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEEs sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Proceduresincluding the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chairhttp://standards.ieee.org/guides/bylaws/sb-bylaws.pdf Carl R. StevensonCarl R. Stevenson as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE Working Group. If you have questions, contact the IEEE Patent Committee Administrator at > doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 2 Co-Authors NameCompanyAddressPhone Paul Piggin Cygnus UK Jianwei Zhang Huawei No. 98, Lane 91, Eshan Road, Pudong, Pudong Lujiazui Software Park, Shanghai, China Linjun Lv Huawei No. 98, Lane 91, Eshan Road, Pudong, Pudong Lujiazui Software Park, Shanghai, China Eli PlotnikParagon Israel Zion HadadRuncom Israel Liwen ChuSTMicroelectronics 1060 E. Brokaw Rd. San Jose, CA USA Kyeongsoo Kim STMicroelectronics 1060 E. Brokaw Rd. San Jose, CA 95131, USA George VlantisSTMicroelectronics 1060 E. Brokaw Rd. San Jose, CA 95131, USA doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 3 Abstract In this presentation, we provide a technical overview of a full proposal for the Physical (PHY) layer and the Medium Access Control (MAC) layer of the IEEE and Sensing solution for Wireless Regional Networks (WRAN) Standard. doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 4 PHY proposal doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 5 What we have Proposed Meeting Incumbents and SP`s Expectations doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 6 OFDMA (Scalable FFT, 2k, 1k, 512) on both Uplink and Downlink enabling a highly flexible and dynamic network resource management, handling of multipath, efficient cellular rollout, efficient multiple access operation and handling of narrow channels (voice) as well as broadband channels (video, data). Other key features: Use of 6, 7 and 8 MHz channel BW or use of available TV channels, optional use of up to 3 channels Aggregation/bonding Power concentration (up to 15db) to boost selective sub- channels to increase range Efficient use of operator spectrum resources Small data granularity (high statistical multiplexing gain) Excellent reuse factor (close to 1) High spectral efficiency in single/multi cell environment Key design Considerations doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 7 Supports adaptive modulation on a per sub-channel basis Excellent handling of interference -- Narrow band interference is rejected through frequency domain processing, while Burst interference is rejected by virtue of the OFDMA symbol length and the per sub-channel interleaving OFDMA supports advanced ranging based on identification of CDMA codes Extremely efficient BW-Request mechanism (90%, CDMA over OFDMA) Extremely low cost network and user equipment Key design Considerations doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 8 System Parameters Parameters SpecificationRemark Frequency range 54~862 MHz (up to 51 channel) System Capacity 75 Mbps (In a cell of 20 km radius) Satisfying user requirements Based on typical deployment scenario using population density of 1.25 persons per 1 sq. km Bandwidth 6, 7, 8 MHz mandatory single channel operation Fractional BW- optional Up to 3 Channel aggregation/bonding- Optional Optional use of up to 3 TV channels, contiguous or non-contiguous need to amend FRD Data rate Maximum: Mbps (64QAM,1/32) Minimum: 5.03 Mbps (QPSK, ) Per 8 MHz channel Spectral Efficiency Maximum: 5.20 bits/s/Hz Minimum: 0.74 bits/s/Hz Apply to all bandwidth Modulation QPSK, 16QAM, 64QAMOn both Uplink and Downlink Transmit power 4W EIRP per CPEAccording to FRD Requirement Multiple Access Adaptive OFDMA on both Uplink and Downlink FFT Mode 512, 1k and 2k Modular Approach, reuse of the same single channel design on other available TV channels Cyclic Prefix Mode 1/4, 1/8, 1/16, 1/32 Duplex TDD ( or FDD in the future) Network topology p-to-mp doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 9 1.System capacity versus range The WRAN system will have to meet the Minimum requirement for system capacity within a cell based on population density as defined in FRD 2.Use of multiple TV channels may be useful (contiguous or aggregated). Addressing Key Requirements doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 10 Scalability Low cost CPE Reuse of the spectrum Computational Complexity deployment in Large cells Macro Diversity Part 1 Part 2 OFDMA based Proposal doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 11 Scalability Scalability is best served using Modular approach where the single channel attributes can be repeated in other available TV channels whether separate or contiguous. Economy of scale entails reuse of proven OFDMA modems to be shortly available meeting one of 16e profiles, such as WiBro, WiMAX doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 12 Low cost CPE Not to exceed EIRP of 4W per CPE will allow a low cost HW and low cost Linear RF chain. In certain cases where isolated islands of users are the prevailing pattern of population distribution, we can use a low power CPE (1W EIRP CPE) and sensing can be delegated to a central entity (repeater) as a part of Macro Diversity solution. doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 13 Power Amplifier Efficiency PAPR Reduction doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 14 In the Up Stream due to Sub-Channel allocation (29 carriers from 1711 usable per OFDM symbol) a 17.7dB gain is achieved for one Sub-Channel allocation, an additional 1-2dB gain is achieved due to lower crest factor for the Upstream. Due to relatively high PAPR (8-10dB) a RF amplifier linearization technology will be used to minimize the need of power backoff from the RF amplifier Combined PAPR reduction and OFDMA gives the optimal solution for a low cost WRAN Power Amplifier Efficiency (1) doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 15 Power Amplifier Efficiency (2) doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 16 Significantly higher efficiency - => longer talk-time; No need for higher supply voltage - Double (or more) power output per transistor => Savings in Silicon real estate. Power Amplifier Efficiency (3) doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 17 OFDMA-2048, 64-QAM PAR is -11 requires 8.0dB backoff PAPR reduction (A-XNN R) can reduce backoff to dB: Increases PA efficiency by >50% % more output power per transistor Power Amplifier Efficiency (4) doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 18 Deployment in large cells From the standpoint of Service Provider it is imperative to offer continuous service with the needed capacity within the cell with the use of only one TV channel, user satisfaction is important, sustainable service is important Cell size is determined by traffic volume generated by users and expected growth potential WRAN may also be deployed in semi-urban areas where more populated areas are expected, hence more cell capacity is needed. doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 19 Deployment Scenario in large cell 30 km radius Simple Business Model for rural area Cell size of 30km radius- 28,260 Sq Km Population density, 1.25 persons/sq km. Estimate number of Households and businesses within the service area is 12,000. Assume a Penetration rate of 30%, 8% of the subscribers are active in the same time. Peak data rate on DL is 1.5Mbps and average data rate on the DL is 400Kbps. Capacity needed on the DL (assuming 75% use of cell capacity) will be 150Mbps Highly conservative estimate of capacity needed is 150Mbps 20 km 3 Channels bonding/aggregation can satisfy required capacity in a cell of 20km radius doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 20 Channels aggregation doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 21 Proposed WRAN Base Station (6 Sectors Antenna Pattern) Use of antenna of 15 dBi gain Use of 3 separate TV channels F1 F2 F3 Offer better use of the spectrum, Low cost Linear PA for each sector, doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 22 Base Station Antenna Pattern Commercial antenna of 15 dBi gain in the operating frequency doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 23 Basic OFDMA Frame doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 24 OFDMA Frame in Two Aggregated Channels doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 25 Downlink Frame Construction doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 26 Low Interference Configuration Macro Diversity doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 27 Low Interference Configuration Macro Diversity Path1 Path2 Low Power Transmission Less than 1W WRAN BS1 BS2 BS3 Array of three separate antennas Area 1 Area 2 HO TV BS Broadcast direction Wireless Mic doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 28 Part 2, Base Line Outline: PHY Requirements & OFDMA basic Features PHY preliminary proposal Base-Band processing chain Down-Link Up-Link Hybrid ARQ Diversity Schemes PAPR reduction Simulation Results doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 29 OFDMA basic features doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 30 Duplexing Technique TDD Multiple Access Method TDMA/OFDMA OFDM Symbols allocated by TDMA Sub-Carriers within an OFDM Symbol allocated by OFDMA Diversity Frequency, Time, Code, Space Basics doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 31 Frame Structure Allowing Flexibility in DL/UL segmentation 3 possible Preamble structure FCH and MAP transmitted in PUSC (for better coverage) Flexible Subchannels allocation per sector on a frame by frame basis All zones are flexible to produce any scenario needed (reuse =1, reuse < 1, STC/AAS) Zone may be used as broadcast [SFN] with permutation adjustment STC/AAS may be combined with regular mode of operation doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 32 Preambles 3 possible Preamble structure, more than 114 preambles over all Preambles are designed for low PAPR (about 5dB or less) Preambles are boosted due to low PAPR Preambles are used for channel estimation, frequency estimation, timing estimation and cell monitoring doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 33 Base-Band Processing Chain doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 34 Base-Band Processing Chain Randomization Coding Tail Biting Convolutional coding (mandatory) CTC/BTC/Zero Tail Convolutional coding (optional) Block size depend on code/modulation/coding rate used and HARQ usage Block size is enlarged as allocation get bigger, limited by a law to constrain decoder complexity (concatenation rules) Bit-Interleaving over each encoded block doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 35 DownLink/UpLink Block Diagram doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 36 Down-Link doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 37 There are two basic modes of operation: Reuse smaller than 1: Sub-Channels (SC) are divided up to 3 Logical-Bands PUSC (Partial use of SC), the structure enables each Logical-Band to have the frequency diversity properties of the full channel, but using only a part of the frequency carriers. The splitting will enable to boost the transmitted carriers on the expense of the un-transmitted carriers ~(4.8 dB) Reuse Of 1: Using PUSC or FUSC (Full use of SC) where all subchannels are used. Cell configuration differ by different permutation enabling a reuse of 1. Reuse doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 38 The Carriers of each Sub-Channel are spread all over the usable frequency for best frequency diversity. The allocation by permutation gives an excellent Reuse factor - almost 1. The allocation by permutation give an excellent interference spreading and averaging. Using Special Permutations for carrier allocation doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 39 DownLink Allocation example (each color - different allocation) doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 40 Forward APC per Sub-Channel Improves the coverage and reduces the interference between sectors in both Uplink and Downlink Enabling the same link budget in the Uplink, for a much smaller PA at the user side Power Control doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 41 DownLink Specification doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 42 FFT size : 2k, 1k and 512. Guard Intervals : , 1/8, 1/16, 1/32 Coding : Convolutional/Convolutional Turbo Code (CTC)/BTC, with coding rates = , 2/3, , 5/6 Additional repetition coding of X2, X4 and X6 QPSK, 16QAM, 64QAM adaptive modulation Different Preamble structure for each sector Pilots embedded within the Symbol Structure(FUSC), or associated per allocation of subchannels (PUSC). 60 Sub-Channels of 48 data subcarriers each (PUSC), for 2k FFT (Scalable for different sizes of FFT) 32 Sub-Channels of 48 data carriers each (FUSC), for 2kFFT DownLink Specification doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 43 Slot Structure is defined differently in each mode: one Sub-channel in the Frequency domain and 1 OFDMA time symbols in the time domain (FUSC), one Sub-Channel in the frequency domain and two OFDMA symbols in the time domain (PUSC). Each slot consists of 48 data modulated carriers. Adaptive Modulation and Coding per Allocation in the Down-Link Forward APC controlling (+9dB) (-18dB) digital gain on the transmitted Sub-Channel DownLink Specification doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 44 DownLink (1) Planned for best delay spread performance Each Cluster can be estimated by itself (self contained) Major Groups include 24/16 clusters (12/8 Subchannels), for an overall 60 Subchannels 60 permutations are possible Subchannel carriers are spread all over the specific Major Groups clusters using RS permutation Clusters are spread all over the spectrum using a permutation doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 45 DownLink (2) Planned for best delay spread performance Planned for a reuse of 1 Pilot periodicity of 2 symbols 32 Subchannels per symbol 32 permutations are possible Subchannel carriers are spread all over the spectrum using RS series All Symbol is estimated as a contiguous block doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 46 Up-Link doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 47 FFT size : 2k, 1k and 512 Guard Intervals : , 1/8, 1/16, 1/32 Coding : Convolutional/Convolutional Turbo Code (CTC)/BTC, with coding rates = 1/2, 2/3, 3/4, 5/6 Additional repetition coding of X2, X4 and X6 PUSC/O-PUSC/AMC/TUSC Subchannel structures QPSK, 16QAM, 64QAM modulation UpLink Specification doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 48 User Can be allocated 1 up to the maximum mini/regular Sub-Channels allocated to the sector Ranging Sub-Channels for User Ranging and fast Band- Width Request by using CDMA over OFDMA technique. Supporting optional Space Time Coding employing Alamouti STC and MIMO operation. Supporting optional Adaptive Array. UpLink Specification doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 49 UpLink Data Mapping Mapping is performed in time axis first, per allocation, for the length of the UL relevant zone Mapping needs only one axis of description (saves signaling overhead) Mapping takes advantage of the power concentration as much as possible doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 50 Up-Link CDMA on OFDMA Ranging and Bandwidth request doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 51 The Carriers of each Sub-Channel are spread all over the usable frequency for best frequency diversity The allocation by permutation gives an excellent Reuse factor - almost 1. The allocation by permutation give an excellent interference spreading and averaging. Using Special Permutations for carrier allocation doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 52 Carriers are allocated by a basic series and its cyclic permutations for example: Basic Series: 0,5,2,10,4,20,8,17,16,11,9,22,18,21,13,19,3,15,6,7,12,14,1 After two cyclic permutations we get: 2,10,4,20,8,17,16,11,9,22,18,21,13,19,3,15,6,7,12,14,1,0,5 Using Special Permutations for carrier allocation doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 53 Ranging using CDMA like modulation doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 54 The CDMA like synchronization is achieved by allocating several of the usable Sub-Channels for the Ranging process, the logic unit they consist is called a Ranging Sub-Channel. Onto the Ranging Sub-Channel users modulate a Pseudo Noise (PN) sequence using BPSK modulation The Base Station detects the different sequences and uses the CIR that he derives from the sequences for: Time and power synchronization Decide on the user modulation and coding Using CDMA like modulation for Ranging doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 55 Ranging Signals Using CDMA over OFDMA modulation ranging designed for Reuse of 1 and Reuse th n, this signal is NTSC If F 103 /F 1200 > th d, this signal is DTV Average frequency component values for several symbol periods to have better sensing results doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 89 METHOD 1 (4) SENSING INCUMBENT SIGNALS Sensing procedure for wireless microphone signals Two types of wireless microphone systems according to frequency usage Single frequency systems Frequency agile systems Wireless systems should NOT be operated on the same frequency as a local TV station. Only open (unoccupied) frequencies should be used. In the U.S., each major city has different local TV stations. Microphone signal detection procedure: sensing the spectral components using FFT devices For ex., for every 3 KHz in a 6 MHz band a spectral component is measured and compared with other components: two comparison methods used for DTC and NTSC signals can be applied If considerable components in a 200 KHz band exist, a wireless microphone is considered to be operated in that band: For the previous case, if consecutive six components spaced equally in 200 KHz have considerable amount of energy, a microphone signal is detected. Or much correlation with stored microphone signals exists, a wireless microphone is considered to be operated in that band. doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 90 METHOD 2 (1) SENSING INCUMBENT SIGNALS After DTV transition in the U.S., VHF low band: Chs MHz VHF high band: Chs MHz UHF band: Chs MHz * n consecutive bands in VHF High or UHF band selected for WRAN services The whole band of n bands is divided into n*l subbands Each band has l subbands; each subband has 6000/l KHz bandwidth At receiver, the received signal after down conversion is inputted to a l*n point FFT By comparing FFT output signals, currently operated incumbent users can be identified and categorized NTSC, DTV, or Part 74 devices With this method all incumbent signal throughout the whole band (n TV bands) can be detected simultaneously Periodically all CPEs and BSs can do this sensing to update the list of active incumbent users * Ch 37 is reserved for radio astronomy doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 91 METHOD 2 (2) SENSING INCUMBENT SIGNALS NTSC signal sensing After down conversion with (f p +1.25) MHz frequency shift, the received signal is inputted to l*n point FFT devices Compare the FFT outputs DTV signal sensing After down conversion with (f p ) MHz frequency shift, the received signal is inputted to l*n point FFT devices Compare the FFT outputs Part 74 device sensing After down conversion with f p MHz frequency shift, the received signal is inputted to l*n point FFT devices Compare the FFT outputs Various comparison methods can be considered Correlation method or pilot detection method used in Method 1 is suggested for TV signals If some consecutive strong components in 200 KHz exist, Part 74 device is considered to operate in this band. Or correlation method will be applied for Part 74 device signals. doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 92 METHOD 2 (3) SENSING INCUMBENT SIGNALS Select k consecutive bands out of n bands f Band 0Band 1Band k-1Selected bands subband 0 subband 1 subband 2 subband l-1 WRANIncumbent userWRANWRAN/incumbent doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 93 SPECTRAL CORRELATION (EXAMPLE) 8 measured spectral components Using 8 measured components, a correlation is calculated. doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 94 PROPOSED RECEIVER STRUCTURE At receiver, data receiving and incumbent signal sensing are executed simultaneously. Without having separate receiving and processing branches Using sensing method 2 If more precise sensing is needed, sensing method 1 may be applied with an additional signal processing block needs one more ADC and FFT. receive antenna LNA cos2f p t where f p : left edge freq. of the channel (or whole target band) LPFADCFFT detector demod doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 95 ADVANTEGES OVER OTHER PROPOSED SCHEMES Advantage over energy detection including MRSS At one measurement, all frequency components can be extracted: whole frequency band can be covered for one FFT symbol duration : faster than MRSS which uses sweep oscillators. Correlation detection not energy detection : more intelligent sensing than MRSS Advantage over cyclostationary feature sensing Can detect Part 74 device signals while cyclostationary sensors can not detect them while NTSC and DTV signals can be detected relatively much easier than Part 74 signals. Advantage over other proposed schemes Need not more hardware to sense: can use OFDM receiving blocks: only a detector should be added for sensing Faster and simpler than other proposed schemes doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 96 Alternative WRAN Sensing scheme Scanning of +/- 8 channels from both sides of WRAN operating channel 50 steps of 2MHz each fed to the tuner Extracting signal signature within the scanned band will take 15 msec doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 97 CHANNEL SENSING Guard intervals for extra quiet period in TDD WRAN systemGuard intervals for extra quiet period in TDD WRAN system Region-based Bayesian method for RF sensing in WRAN systemRegion-based Bayesian method for RF sensing in WRAN system Pilot design for channel estimation and interference detection in WRAN systemPilot design for channel estimation and interference detection in WRAN system doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 98 Guard intervals for extra quiet period in TDD WRAN system doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 99 Background Synchronous Quiet PeriodSynchronous Quiet Period a period in which all WRAN devices stop transmission in all channels available in the system used for sensing the signals in all channels of the system without interfering the system itself useful to enhance awareness to the surrounding radio environment Guard IntervalsGuard Intervals When using OFDMA at the physical layer, guard intervals should be inserted at the switching points of transmission, OFDM symbols of different users can be synchronized at BS. We can use these guard intervals as extra quiet periods for sensing! 1 CPE1 (d=0) CPE2 (d=R) GIDownlink sub- frame Uplink sub-frame 1 GIDownlink sub- frame Uplink sub-frame [R: cell radius] doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 100 Our Proposed Design (1) Feature 1: Adaptive Guard Interval Control Conventionally, CPE1 should wait for CPE2 during the uplink transmission such that their first uplink symbols are synchronized at BS. We relax the above constraint: 1 CPE1 (d=0) CPE2 (d=R) GIDownlink sub-frame Uplink sub-frame 1 GIDownlink sub-frame Uplink sub-frame *CPE2s first UL symbol is synchronized with CPE1s second UL symbol * CPE2s first UL symbol is synchronized with CPE1s second UL symbol doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 101 Our Proposed Design (2) Feature 2: Asynchronous Quiet Period Guard intervals from UL to DL can also be used as extra quiet period for channel sensing. Depending on the demand for sensing accuracy, some OFDM symbols can be replaced by the sensing period Flexibility is ensured BS notifies the assignment of such sensing periods to the CPEs by using the proposed Sensing Period Assignment (SPA) message. 1 Downlink sub-frame Uplink sub-frame 5 With adaptive guard interval control CPE3 (0 95%) for 2 second of operation period and 100ms of minimum quiet time doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 176 Summary of DFH with Clean Sensing Feasible Clear sensing can be guaranteed with non-interrupted data transmissions Compatible System synchronizations can be done by extending the frame (super-frame) synchronization method Switch to non-hopping mode if hopping conditions are not sufficient Promising channel utilization doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 177 Frequency Hopping Collision doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 178 Collision Avoidance for Channel Switching Resolve hidden node problem for channel switching Cognitive Frequency Hopping/Collision Avoidance (CFH/CA) algorithm Announce CFH decisions to neighbor systems Wait for conflicting announcements Perform CFH when switching collision is guaranteed to be avoided. doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 179 DFH Collision Avoidance doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 180 doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 181 DFH/CA + Selective Sensing on Multiple Channels doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 182 Key Advantages of DFH with Selective Sensing Reliable RF Sensing Performance Selective sensing with Sufficient sensing time Support sensing of large number of channels w/o QoS concerns Timely Licensed Incumbent Protection Fulfill timing requirements imposed by incumbents QoS Satisfactory for License Exempt Systems Latency Avoid sensing latency required by quiet sensing schemes Throughput Avoid sensing overhead required by quiet sensing schemes doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 183 Key Advantages of DFH with Selective Sensing Low Implementation Cost Future-proof Tolerable to more restricted sensing requirements in the future Sensing techniques insensitive Allow longer sensing time from simple sensing techniques DFS messaging algorithms insensitive Allow longer DFS messaging time from simple DFS messaging algorithms Marginal hardware cost increase Only need a simple 2nd receiver for simultaneous RF sensing. doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 184 Key Advantages of DFH with Selective Sensing Flexible Framework for RF Sensing Control and DFS control Cognitive Frequency Hopping Modes Quiet Sensing Mode Multiple-channel Operation E.g. Channel bonding doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 185 DFS Messaging Control doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 186 DFS Messaging Control DFS Messaging Algorithm DFS Messages PHY Supports 1uS resolution monitoring Accurate threshold setting for detection Sub-frame frequency agility (for monitoring) doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 187 DFS Messaging Control Key Advantages Reliable, efficient, and flexible mechanism for channel measurement reporting and DFS announcements Sufficient messaging time guaranteed without affecting data transmission QoS such as latency and throughput Simultaneously performed DFS messaging Algorithm doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 188 DFS Messaging Algorithm doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 189 Contents of Spectrum Sensing Results Detect at least 4 channel conditions: 1.Licensed incumbent occupied 2.Another system occupied 3.Noisy 4.Vacated/clean Sensing reports Bit-vector and on-request raw data Balancing efficiency and accuracy of sensing reports Validation time For non-incumbent-occupied channels doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 190 Report Scheduling Polling BS polls CPEs to report through uplink (UL) MAP that schedules TX opportunities for CPE reporting the UL MAP may provide redundant transmission opportunities for CPEs reporting Poll-me CPE requests for reporting, 1-bit flag in BW request PDU Contention CPE requests for reporting or sends report via contention opportunities (contention sub-channel/window) doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 191 Report ACK and Re-scheduling Explicit report reschedule The BS re-schedules those CPEs from which it failed to receive the sensing reports in a subsequent UL MAP Implicit report acknowledgement The BS ACKs the successful reports by not scheduling in a subsequent UL MAP those CPEs from which it received their sensing reports doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 192 DFS Decision DFS decision-making The BS decides the valid channels to be used for the whole system in the next DFH period by summarizing all measurement reports Decisions could be made by as simple as logical ORs DFS decision announcement DFS decision shall be announced to all CPEs in the system, and to all neighbour BSs. Adjustment to prevent defective decisions BS adjusts DFS decisions according to feedbacks from CPEs and neighbour BSs doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 193 MAC Messages for DFS MAC messages is already available in the MAC message is in section: Channel measurement Report Request/Response (REP- REQ/RSP) ( cor1) TLVs (which form the content of the MAC message are at: REP-RSP management message encodings) See the next slide doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 194 MAC Messages for DFS: TLVs doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 195 Detection Scenario and MAC messaging doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 196 Support for Interference Mitigation and Coexistence Protections of licensed incumbent services RF Sensing Control DFS Messaging Control LE systems coexistence and sharing Spectrum sharing mechanism Inter-system communications doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 197 Co-existence of Systems doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 198 Co-existence of Systems Objectives Fair and efficient spectrum sharing mechanism Efficient inter-system communications for collaborative coexistence Proposed Techniques On-demand Spectrum Contention Spectrum contention mechanism with integration of DFS and TPC Logical control connections Over-the-air + over-the-backhaul doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 199 Spectrum Sharing Mechanism On-Demand Spectrum Contention (ODSC) doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 200 Key Properties of ODSC Integrate dynamic frequency selection (DFS) and transmission power control (TPC) with dynamic spectrum contentions Provides fairness, efficiency and adaptivity of spectrum access using active inter-system coordination doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 201 Key Properties of ODSC Efficiency Low coexistence overhead Coexistence overhead is only incurred on demand No constant overhead Low overhead inter-system communications that are overlapped with data transmissions Low complexity Simple contention mechanism No complex coordination mechanism that is usually required for TDMA-based solutions Distributed decision-making -- scalable doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 202 Key Properties of ODSC Fairness Contention based Solution Fair spectrum access for every system at any moment Local fairness Iterative process Long-term global (multi-system) fairness doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 203 Key Properties of ODSC Adaptivity Highly adaptive to operation demands Internal demand: channel conditions and workload conditions External demand: coexistence (spectrum contention) requests doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 204 doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 205 On-Demand Spectrum Contention (ODSC) Algorithm Channel Evaluation and Selection Select spectrum holes (available channels) Operations: RF sensing Measurement (sensing results) evaluations Measurement reporting Report processing Frequency selection doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 206 On-Demand Spectrum Contention (ODSC) Algorithm Verifying the Feasibility of Non-Exclusive Channel Sharing Channel sharing through transmission power control (TPC) such that systems sharing the same channel do not cause harmful interference to one another Non-exclusive spectrum sharing method is feasible as long as the maximum achievable signal-to-interference- ratio (SIR) on the selected channel is higher than the required SIR of the for the supported services doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 207 On-Demand Spectrum Contention (ODSC) Algorithm Channel Contention for Exclusive Channel Sharing Facilitated by Inter-System Coordination through explicit contention messaging Basic contention components Contention requests Contention resolution Contention responses Contention messaging through inter-system control connections doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 208 On-Demand Spectrum Contention (ODSC) Algorithm Operations if Non-Exclusive Channel Sharing feasible The system acquiring the channel schedules data transmissions on the channel with proper transmission parameters (such as transmission power) Collision avoidance of channel switching shall be applied doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 209 On-Demand Spectrum Contention (ODSC) Algorithm Operations after Channel Contentions for Exclusive Channel Sharing The system acquiring the channel, if won, Schedules data transmissions on the channel starting from the time agreed upon by both contending systems After a Grace Period starting from the point of contention resolution Collision avoidance of channel switching shall be applied The system using the channel, if lost, Releases the channel starting from the time agreed upon by both contending systems (after a Grace Period) doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 210 On-Demand Spectrum Contention (ODSC) Algorithm Iterative Spectrum Sharing Processes Initiated On- Demands Internal Demands Initiated by a WRAN itself To Fulfill the internal QoS requirements of a system Based upon the following dynamic conditions Channel condition Workload condition External Demands Coexistence requests from other systems doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 211 doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 212 Dynamic Frequency Hopping Working with On-Demand Spectrum Contention doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 213 Evaluations of ODSC Evaluating the Feasibility, Fairness, and Efficiency of the proposed spectrum sharing mechanism (ODSC) Simulation Methodology Tool Network Simulator (NS2:)http://www.isi.edu/nsnam/ns/ Evaluation Metrics Channel Occupation Time (Throughput); Service Interruption Time (Minimum Service Delay) Simulation Scenarios 10 Coexistence Scenarios are evaluated; Simulation Parameters Simulation Time: 6000 seconds Channel check period: 1ms Channel release grace period: 10ms Single-channel operation doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 214 Scenario #1 Total Channel Occupation Time Total Service Interruption Time Number of Service Interruptions Maximum Service Interruptin Time Average Service Interruption Time WRAN WRAN Single channel sharing doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 215 Scenario #2 Total Channel Occupation Time Total Service Interruption Time Number of Service Interruptions Maximum Service Interruptin Time Average Service Interruption Time WRAN WRAN WRAN Single channel sharing doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 216 Scenario #3 Total Channel Occupation Time Total Service Interruption Time Number of Service Interruptions Maximum Service Interruptin Time Average Service Interruption Time WRAN WRAN WRAN WRAN Single channel sharing doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 217 Scenario #4 Total Channel Occupation Time Total Service Interruption Time Number of Service Interruptions Maximum Service Interruptin Time Average Service Interruption Time WRAN WRAN WRAN Single channel sharing doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 218 Scenario #5 Total Channel Occupation Time Total Service Interruption Time Number of Service Interruptions Maximum Service Interruptin Time Average Service Interruption Time WRAN WRAN WRAN WRAN Single channel sharing doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 219 Scenario #6 Total Channel Occupation Time Total Service Interruption Time Number of Service Interruptions Maximum Service Interruptin Time Average Service Interruption Time WRAN WRAN WRAN WRAN Single channel sharing doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 220 Scenario #7 Total Channel Occupation Time Total Service Interruption Time Number of Service Interruptions Maximum Service Interruptin Time Average Service Interruption Time WRAN WRAN Double channel sharing doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 221 Scenario #8 Total Channel Occupation Time Total Service Interruption Time Number of Service Interruptions Maximum Service Interruptin Time Average Service Interruption Time WRAN WRAN WRAN Double channel sharing doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 222 Scenario #9 Total Channel Occupation Time Total Service Interruption Time Number of Service Interruptions Maximum Service Interruptin Time Average Service Interruption Time WRAN WRAN WRAN WRAN Double channel sharing doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 223 Scenario 10 Total Channel Occupation Time Total Service Interruption Time Number of Service Interruptions Average Service Interruption Time Standard Variation Interruption Time WRAN WRAN WRAN WRAN WRAN WRAN WRAN doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 224 Simulation Results Summary doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 225 Inter-System Communications Logical Control Connections doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 226 Logical Control Connections (LCC) Connection based inter-system communications Reliable, efficient Enable the feasibility and overall efficiency of the collaborative coexistence mechanism Established and maintained both over the air and over the backhaul doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 227 Logical Control Connections (LCC) Very low communications overhead incurred in terms of Spectrum bandwidth Messaging latency Hardware/software complexities doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 228 Over-the-air Logical Control Connections Key Concepts Bridge-CPE Co-existence Connection Co-existence Association Over-the-air control connection Service connection + coexistence connection doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 229 Bridge CPE Located in the overlapping area of two cells Associated with one BS (service BS) through service connections; Associated with another BS (coexistence BS) through coexistence connections Coexistence communications only doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 230 Co-existence Connections Regular connections Carry co-existence communications only Established and maintained Between a bridge CPE and the coexistence BS (C-BS) on request by the service BS (S-BS) Between two BSs if S-BS is within the arrange of C-BS S-BS behaves as a CPE of C-BS in such case) On channels occupied by the coexistence BS doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 231 Co-existence Connections Establishment/maintenance performed along with service data transmission Ranging, connection acquisition Controlled by S-BS and shall be guaranteed that they are not co-scheduled with service communications doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 232 LCC Between Two Base Stations doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 233 Over-the-Air Co-existence Communications S-BS communicates with C-BS for co-existence via B-CPE as a relay Communications via Service connection + coexistence connection S-BS controls the coexistence operations between B-CPE and C-BS Coexistence communications Messaging for spectrum contention/negotiation, Sensing measurement sharing, Operation parameter (transmission power, channel in-use, etc.) announcement doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 234 Coexistence Communications Control S-BS controls the coexistence communications (operations) between B-CPE and C-BS doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 235 Over-the-Backhaul Logical Control Connections Used to establish and maintain inter-system communications when Over-the-air communications is not feasible. doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 236 Co-existence Management Entity doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 237 Co-existence Management Messages Respond2Get(MIBParams, SRC, DST);Get(MIBParams, SRC, DST); Respond2Reqest(CoexistMesg, SRC, DST);Reqest(CoexistMesg, SRC, DST); Respond2Set (MIBParams, SRC, DST);Set (MIBParams, SRC, DST); Source CoexistME Destination CoexistME Respond 2Get(MIBParams, SRC);Respond 2Get(MIBParams, DST); Respond 2Request(CoexistMesg, SRC);Respond 2Reqest(CoexistMesg, DST); Respond 2Set(MIBParams, SRC);Respond 2Set(MIBParams, DST); Respond 2Set(MIBParams); CoexistME MACMAC CoexistME Get(MIBParams, SRC);Get(MIBParams, DST); Request(CoexistMesg, SRC);Reqest(CoexistMesg, DST); Set(MIBParams, SRC);Set(MIBParams, DST); Set (MIBParams); CoexistME MACMAC CoexistME Destination Base StationSource Base Station doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 238 Conclusion (MAC) Complete, efficient, and flexible MAC solutions for interference mitigation and coexistence support Protections of licensed incumbent services Sensing Algorithm based on Database and RF Sensing RF Sensing Control: Selective Simultaneous RF Sensing DFS Control: Dynamic Frequency Hopping DFS Messaging Control based on MAC Messages LE systems coexistence and sharing Spectrum sharing mechanism using ODSC Inter-system communications using LCC doc.: IEEE /0030r2 Submission March 2006 Huawei, NextWave, Runcom, STMicroelectronics Slide 239 Questions and Answers