Download - Presented at: Wireless @ Virginia Tech 2012 Symposium & Summer School on Wireless Communications
Presented at:
Wireless @ Virginia Tech2012 Symposium & Summer
School on Wireless Communications
May 31, 2012
Kenneth R. Baker, PhDUniversity of Colorado at BoulderInterdisciplinary Telecommunications Program
Wireless Antenna Distribution and LTE HetNets
CU-Boulder
2Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Thesis
Indoor Distribution as path for LTE HetNets• An introduction to Indoor and Outdoor
Distributed Antenna Systems.
• State of the art today
• Describe how these systems form a migration path to hierarchical cell structures planned for 4G/LTE cellular networks.
• A review of LTE HCS related standards
3Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
DAS Systems
A Distributed Antenna System (DAS) is a network of spatially separated
antenna nodes connected to a common source via a transport medium that
provides wireless service within a geographic area or structure (the DAS
Forum)
Provide better coverage in environments like:
• Outdoor: Highways, Downtowns, Subways, Tunnels, University Campuses
• Indoor: Corporate Offices, Stadiums, Shopping Complexes, Airports,
Convention Centers, Hospitals, Hotels etc.
60% of voice traffic and 90% of data traffic from indoors. (ABI Research)
DAS systems with overall market value of $5.5 billion comprises 96% of
indoor systems (ABI Research)
DAS Concept was introduced by Saleh etal in 1987 as a solution for better indoor
coverage using leaky coax cable to simulcast the RF signal. (A.A.M. Saleh, A.J. Rustako, and
R.S. Roman, “Distributed antennas for indoor radio communications,” IEEE Trans. Commn., vol. 35, pp. 1245–1251,
Dec. 1987)
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4Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Why DAS is needed?
Indoor:
• Poor coverage in basements, higher floors (above 25 floors), elevators, inner rooms (due to wall attenuations).
• Large reflections from walls, roofs, tinted glass windows.
Outdoor:
• Other buildings block the coverage in dense areas like downtowns.
• To provide coverage to long Highways/tunnels.
5Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
DAS Components
Donor Unit
• BSS, External Antennas
Interconnection Network
• Active & Passive Head
Ends and Distribution
Units
• Coax/Fiber/Repeaters
• Star or Cascade
Connections
Remote Unit
• RAUs & multi/wide band
antennasImage source: http://www.accu-tech.com/das/
5
6Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Example Airport DAS
7Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Example: Outdoor DAS
Outdoor DAS serving a University Campus
• Neutral Host System• Two Cellular
Operators share the transport infrastructure
• They also share antennas
8Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
9Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Interconnection Media
Coax
• Cables: 50 ohm (RG174, RG58, LMR240, Standard Heliax etc)
• Connectors: SMA, BNC, TNC, N, 7/16 etc.
• Other Components: Couplers, Splitters, Bi-Directional Amplifiers
Optic Fiber
• Cables: Single Mode, Multimode, Step Index, Graded Index
• Connectors: FC,SC, ST, LC or MTRJ
• Other Components: Splicers, Splitters, Attenuators, WDM multiplexers, Laser Diodes
Over the Air (RF)
• Repeaters or Bi-Directional Amplifiers (BDA),
• Antennas: Isotropic, Dipole, Yagi, Panel, Leaky Coax
Hybrid Fiber Cable (HFC): CATV Networks
10Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Benefits of DAS (Chow, et al. 1994)
RADIO RADIO
Single Antenna System DAS
• Consider single slope propagation model:
d
• PT = Transmitted Power• PR = Received Power• C = Path loss at reference
distance• γ = Path loss exponent
• d = radius of the macro-cell• A = area of the macro-cell = πd2
11Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Benefits of DAS (contd.)
Improvement in Coverage:• Area of coverage of single antenna is given by:
• Assuming transmitted power is equally divided between N antennas of the DAS, area covered by each individual antenna is given by:
= = …. =
• Therefore, total area:
• Thus, coverage is increased by a factor of:
12Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Benefits of DAS (contd.)
Reduction in Transmit Power (Forward Link):For single antenna system: Assuming transmitted power is equally divided between N antennas of the DAS:
• Therefore, total area:
• Thus, transmitted power is reduced by a factor of:
• On Reverse Link, assuming that path loss is reciprocal, mobiles have to transmit only 1/N of the base station to communicate to a single DAS antenna. Thus power is reduced by a factor of:
13Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Q. What’s the vision? A. Small Cells
Heterogeneous Networks• a.k.a. Multi-Tier Networks
• Better Coverage, More Capacity
Incorporated in 3GPP LTE Standards• Includes New Network Elements
• Includes Interference and Mobility Management Techniques
14Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Indoor Distribution Today
• Outdoor DAS
• Indoor DAS
• Neutral Host vs. Single Carrier
• Passive vs. Active
The first steps to HetNets …• WIFI Off-load in Stadiums
• Femtocells (Home Node-B’s)
15Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Indoor Distribution Today
• Outdoor DAS
• Indoor DAS
• Neutral Host vs. Single Carrier
• Passive vs. Active
The first steps to HetNets …• WIFI Off-load in Stadiums
• Femtocells (Home Node-B’s)
16Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Sports Stadium as a Specific Example
17Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Stadium Traffic Facts (with 60-90K Fans)
Traffic Statistics from a Sports Stadium
Example Traffic profiling look at data services usage during a game
42%
24%
15%
12%6% 2%
Streaming Web browsing
App Store Access Smartphone Apps
Email Other
Voice calls: 30-60K
SMS: 200-600K
Data Volume: 4-9 GB
Data Calls: 300K-1M
Numbers are cumulative over the duration of a game
Data services used during events
Data services on Smartphones are driving the traffic today
Background traffic from applications like Twitter, Email, etc. is a significant contributor
18Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Stadium Traffic Will Continue to Increase
It is expected that mobile video will account for the majority of data growth
19Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Stadium Antennas
20Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Bowl Design and Some Statistics
Stadium No. WiFi APs No. SectorsNo. 1.25 MHz
Carriers (Voice/Data)
U. Michigan ~ 15 5/7
Met Life ~ 12 8/9
Lucas Field 1020 15 5/9
Mile High 500 12 6/8
21Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Super Bowl Data Usage
(One of three operators)
22Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Offload will get easier: “Hot Spot 2.0”
Three components:1. IEEE 802.11u
• Pre-association
• published on February 25, 2011
2. Wi-Fi Protected Access 2 (WPA2)-Enterprise3. Extensible Authentication Protocol (EAP)
• EAP-SIM (GSM)
• EAP-AKA (UMTS)
Mobility Services Advertisement Protocol (MSAP)• transported via IEEE 802.11u Generic Advertisement
Service (GAS)
See also: IEEE 802.21• enables seamless handover between networks
23Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Indoor Distribution Today
• Outdoor DAS
• Indoor DAS
• Neutral Host vs. Single Carrier
• Passive vs. Active
The first steps to HetNets …• WIFI Off-load in Stadiums
• Femtocells (Home Node-B’s)
24Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Femtocell Overview
Femtocell• Ethernet Backhaul
• In-home base station
• Enterprise Base Station
Minimal Customer Requirements: • Any wireless handset or data device
• A broadband connection and router
Femtocell
ISP
xDSL/Cable Modem
Core Network
GPS
3 Satellites
25Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Example: Dual-Mode EvDO product
Bottom Line: It’s a Plug and Play Cellular Base Station
26Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Femtocell Interference
Femtocells as two tier network• Open: Any cell phone can attach
• Closed: Only specified cell phones can attachBS of
Macro cell
Femto Cell Femto Cell
Femto Cell Femto Cell
Femto BS
Legend
Connection to BS
Interference from Macro to Femto and Femto to
Macro
Interference form Femto to Femto
User of Macro cell
Femto BS
Femto BS
Femto BS
User of Femto cell
Downlink Femtocell Interference
27Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Femtocell Summary
3G Femtocells Today:• Can hand out to the macro layer
• Cannot hand-in from the macro layer
4G (LTE) Femtocells:• Will enable both hand-in and hand-out between the
femto layer and the macro
• Femto to Femto handover should also be possible.
28Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Looking ahead to LTE
• Carrier Aggregation
• Higher Order Modulation
• 4G
• MIMO
IEEE 802.16Fig. after Nokia Siemens
29Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Why LTE?
30Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
LTE, LTE-A, and 4G
31Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
LTE Network
MME: Mobility Management Entity• Manages mobility, UE Identity and
Security Parameters
S-GW: Serving Gateway• Evolved Packet Core Interface to E-
UTRAN
P-GW: Packet Gateway• Evolved Packet Core Interface to
Packet Data Network
eNB: Evolved Node B• Performs all Radio Interface Related
Functions
Interfaces• X2: between eNBs
• S1: between eNB and MME/S-GW
32Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Network Elements
Element Backhaul Coverage Antennas
Macro-Cell S1* ≥ 500mAt or above rooftop level
Pico-Cell S1*≤ 500m, Indoors
Rooftop or below
Femtocell IP Indoors Tabletop
Relay LTE≤ 500m, Indoors
Below rooftop
*S1-C: Stream Control Transmission Protocol / IP (SCTP/IP) stack*S1_U: GSRP Tunneling Protocol/UDP5/IP stack
33Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Pico-Cells … Heterogeneous Networks
Increasing data rate requirements• Need better SNR
Increasing capacity requirements• Need more cells
Ergo: Put cells where the users are• Trend is to complement
macro network with picocells
• Possible with LTE Rel.8
• Enhancements with Rel. 11
Picocells• S1 interface for backhaul,
not ethernet
Picocells exist today in 3G networks
34Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Relay Nodes
Donor eNB uses LTE as backhaulEither in-band or out-of-band
RNB
RUEMUE(Donor) eNB
Backhaul Link(Un)
Relay Node Access Link(Uu)
Macro UE Relay UE
Relay Cell
Donor Cell
(Uu)
35Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Example Application: Public Safety
See: Order and Fourth Further Notice of Proposed Rule Making, FCC11-6, “In the Matterof Service Rules for the 698-746, 747-762 and 777-792 MHz Bands; Implementing aNationwide, Broadband, Interoperable Public Safety Network in the 700 MHz Band;Amendment of Part 90 of the Commission’s Rules,” January 25, 2011
36Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Outage Probability as a Function of No. of Relays
Ref. Tin-Ei Wang, unpublished work
37Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
LTE Heterogeneous Networks
Network Elements• Relays
• Pico Cells
• Femtocells (Home Node B)
Need tight coordination for Handover and Interference management
• Negative Impact at small cell edges
• Small cells need handover management
38Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
LTE Heterogeneous Networks
LTE Network Solutions:• Soft Cell
• Enhanced Inter Cell Interference Coordination (eICIC)
• CoMP
• Self-Organizing Networks (SON)
• Dynamic Load Balancing
• Carrier Aggregation
39Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Enhanced Local Access: Soft Cell
In LTE Advanced:Pico does not create a new cell but is an extension of an overlaid macrocell• Macro – basic coverage (system info, data, control
• Pico – enhanced capacity and data rates
Consider this a macro assisted pico layer
40Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Inter-cell Interference Coordination (ICIC)
Release 8 (LTE)• Interference mitigation by coordinating DL control and
data channels
• lowering the power of a part of the sub-channels in the frequency domain
Release 10 (LTE-A)• coordinate blanking of sub-frames in the time domain
in the macro cell
• Only legacy broadcast signals and channels are transmitted to support legacy Rel 8 UEs
41Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Originalreuse
ICIC Example
ICIC Rel. 8 SINR Distribution Example
-5 dB 20 dB
42Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
CoMP
Coordinated Multipoint TransmissionIncreases Data Rate
• coordinating and combining signals from multiple antennas
43Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Rel. 10/11 CoMP
Downlink• joint processing (JP)
• coordinated scheduling (CS)
• coordinated beamforming (CB)
Uplink• joint reception (JR)
• Coordinated scheduling (CS)
44Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Self-Optimizing Networks (SON)
“Self-Optimizing and Self-Configuring”• Needed to manage tiersIdentified Use Cases:• Energy Savings
• Interference Reduction
• Automated Configuration of Physical Cell Identity
• Mobility robustness optimization
• Mobility Load balancing optimization
• RACH Optimization
• Automatic Neighbor Relation Function
• Inter-cell Interference Coordination
3GPP TR 36.902 V9.3.1 (2011-03)
Note: HCS is not mentioned specifically in 36.902
45Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Dynamic Load Balancing
• Between tiers• Listed as a function of the X2 interface:“This function allows exchanging overload and traffic load information between eNBs, such that the eNBs can control the traffic load appropriately. This information may be spontaneously sent to selected neighbour eNBs, or reported as configured by a neighbour eNB.”
• 3GPP TS 36.420 V10.2.0 (2011-09)
46Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Carrier Aggregation
Between bandsBetween tiers
47Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
DAS or Femto?
1. ABIresearch2. IBW Solution and Capacity Offload in 3G and LTE (IBW symposium)
Summary of solution comparison
Metric Femto DAS
Equipment + Labor Costs1 $.05-$.1 per sq. foot
Active DAS - $0.25 - $ 0.5 per sq. foot.
FlexibilityHigh, technology, coverage and capacity can be added as needed
Medium, Coverage should be planned at onceCapacity can be modified through sectorization plan Adding technology depends on selected DAS
Multi-operator support2 Requires multiple Femtos Possible
Deployment ModelPlug and play solution, with limited setting for Enterprise Femto
Requires planning and extensive deployment support (installation, commissioning….)
48Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
One Slide About Backhaul
• The backhaul network needs to be able to support the wireless throughput.
• Backhaul is one of the major expenses for wireless network operators
Max. 802.11b
49Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Motivations for HetNets
Better performance:1. Better coverage
• Chow, et. al, 1994
2. Better SNR• Madhusudhanan, et. al, 2011
Madhusudhanan, P.; Restrepo, J.G.; Youjian Liu; Brown, T.X.;Baker, K.R.; , "Multi-Tier Network Performance Analysis Using a Shotgun Cellular System," Global Telecommunications Conference(GLOBECOM 2011), 2011 IEEE , vol., no., pp.1-6, 5-9 Dec. 2011.
50Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Challenges in Studying a Multi-tier Network
Simulation study of the entire system is computationally infeasible.Ideal hexagonal grid model is not a good model anymore.Certain entities of the network are essentially random in nature.
e.g. the location of the femtocell BSs.
51Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Motivations for considering a Shotgun Cellular System Inspired Model
Shotgun Cellular System (SCS): [Brown 2000] The cellular system where the BS placement is according to a 2-D homogeneous Poisson point process.SCS is a good model the femtocell BSs in the network.The SCS is a surprisingly good model for the macrocell network:
SCS provides a natural lower bound to the cellular performance.
[Brown 2000] The SCS model provides a fair idea about the actual macrocell network. In the strong shadow fading regime, the downlink performance in
an SCS converges to ideal hexagonal grid model. In the normal shadow fading regime, the gap between the
downlink performance in an SCS and in an ideal hexagonal grid model is small.
52Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
System Model
Multi-tier network with tiers of heterogeneous networks.Each tier is an SCS independent of the other tiers.
BS density: .
BS transmission power:
SINR threshold: (same for all tiers)Received power at a distance from a BS of the tier is
Background noise -
Shadow fading factor Path-loss exponent
53Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Performance Metric
Carrier-to-Interference-ratio at the mobile user located at origin
Carrier-to-Interference-plus-noise-ratio Problem:
For the multi-tier network, Characterize the success probabilities: and
(or) the outage probabilities: and .
‘s’ the tier corresponding to the strongest signal at the MS Total interference
power due to the rest of the BSs in the multi-tier network.
54Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Approach
Step1
• , 1-tier network, w/o shadow fading.• , 1-tier network, w/o shadow fading.
Step 2
• 1-tier network, arbitrary fading distribution. • 1-tier network, arbitrary fading distribution.
Step 3
• multi-tier network, arbitrary fading distribution. • multi-tier network, arbitrary fading distribution.
55Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Multi-tier Networks
Having thoroughly studied the single-tier network, we move on to
the multi-tier network.
Multi-tier network with tiers of independent SCSs, represented as
is the number of tiers. is the BS density of the tiers.
is the path-loss exponent.
is the BS transmission powers for the tiers.
is the noise power.
is the shadow fading factor with arbitrary distribution.
ASSUMPTION: The SINR threshold is the same for all tiers.
Theorem: The multi-tier network
is equivalent to a single-tier network where Equivalent BS density
Transmission power of each BS is an i.i.d. random variable such that
56Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Multi-tier Networks: Important Implications
Inclusion of the additional tiers of wireless network: Does not affect the success probability.Improves the success probability when
There is no shadow fading.
The arbitrary shadow fading distribution is such that For example, log-normal shadow fading factors with 0 mean and standard deviation satisfy the above condition.
57Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Madhusudhanan, et. al Conclusions
We have studied the and success probability of a multi-tier network by systematically reducing the network to equivalent networks and finally to a single-tier network that we understand well.As a result, for a multi-tier network where the SINR thresholds of all the tiers are the same, we have
Derived the semi-analytical expression for the and success probabilities for SINR threshold .
Obtained a simple closed form expression for success probability for SINR threshold
The above result matches the results obtained by [Dhillon, Ganti, Baccelli, Andrews, 2011] and [Mukherjee, 2011] who approached the problem in different ways with results restricted only to Rayleigh fading distributions.
Further, we have derived an approximation for the success probability and show the approximation is tight.
All the results derived in the paper hold for arbitrary fading distribution.
58Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
The Path From Today to HetNet
Indoor DASOutdoor DASFemtocellsPicocells
Soft CellsBetter FemtocellsIndoor / IP Connected
HetNetsSONICICCoMPRelays
3G
…
L
TE
...
LTE-
A
59Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
If I were a cellular network operator …
All Technology Decisions are Business drivenFuture will be built upon combining networks1) Entrenched equipment and technology will
drive future deployments1) Capital investment to be fully effectuated.
2) Engineering staff that knows the current technology cannot be redirected instantaneously
2) Leveraging technology to mitigate expenses1) WiFi off-load
60Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Research Issues
Research Issues• Backhaul
• Simulation of Indoor and Outdoor Network Interaction
• Improving Small Cell Handover and Control
• Managing Handover Between Tiers
• Managing Interference Between Tiers
• Taking SON Concepts Across Tiers
• Traffic steering– RAT handovers– layer handovers– resource availability
61Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Bibliography (1/3)
P. Chow, A. Karim, V. Fung, and C. Dietrich. Performance advantages of distributed antennas in indoor wireless communication systems. In IEEE Proceedings of Vehicular Technology Conference, 1994, volume 3, pages 1522 – 1526, June 1994. Timothy X Brown, “Cellular performance bounds via shotgun cellular systems”, IEEE Journal on Selected Areas in Communications, vol. 18, no. 11, pp. 2443-2455, Nov 2000. H. S. Dhillon, R. K. Ganti, F. Baccelli, J. G. Andrews, “Modeling and analysis of K-tier downlink heterogeneous networks”, IEEE Journal on Selected Areas in Communications, to appear in Apr 2012.S. Mukherjee, “Downlink SINR distribution in a heterogeneous cellular wireless network with max-SINR connectivity”, Allerton Conference on Communication, Control, and Computing, Sep 2011.Madhusudhanan, P.; Restrepo, J.G.; Youjian Liu; Brown, T.X.; Baker, K.R.; , "Multi-Tier Network Performance Analysis Using a Shotgun Cellular System," Global Telecommunications Conference (GLOBECOM 2011), 2011 IEEE , vol., no., pp.1-6, 5-9 Dec. 2011.
62Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Bibliography (2/3)
Blaze Vincent, Reverse Link Analysis and Modeling of CDMA based Distributed Antenna Systems. Thesis (M.S.)--University of Colorado, Dec. 2011. See also references therein.Tin-Ei Wang, CU Boulder, unpublished work, 2012Ching-Pu Wu, K. Baker, “Comparison of LTE Performance Indicators and Throughput in Indoor and Outdoor Scenarios at 700 MHz,” to be published: Proc. IEEE 76th Vehicular Technology Conference, VTC2012-Fall, Québec City, Sept. 2012.Christophe Chevalier, “Expanding 3G Coverage: Indoor and High Capacity Venues,” Presentation material, Qualcomm Inc.Jon M. Peha, et. al, “The Public Safety Nationwide Interoperable Broadband Network: A New Model for Capacity, Performance and Cost,” FCC White Paper: DOC-298799A1, June 2010. http://transition.fcc.gov/pshs/docs/releases/DOC-298799A1.pdfJames Arden Barnett, Jr., Jennifer A. Manner, FCC Public Safety and Homeland Security Bureau, Presentation to: 2010 UASI National Conference, New Orleans, LA, June 22, 2010S. Kishore, L. Greenstein, H. Poor, and S. Schwartz, “Uplink user capacity in a CDMA macrocell with a hotspot microcell: exact and approximate analyses,” IEEE Trans. Wireless Commun., vol. 2, no. 2, pp. 364–374, Mar. 2003.——, “Uplink user capacity in a multicell CDMA system with hotspot microcells,” IEEE Trans. Wireless Commun., vol. 5, no. 6, pp. 1333–1342, June 2006.
63Ken Baker (http://morse.colorado.edu/~kkbaker/)May 31, 2012
Bibliography (3/3)
S. Kishore, L. J. Greenstein, H. V. Poor, and S. C. Schwartz, “Uplink user capacity in a CDMA system with hotspot microcells: effects of finite transmit power and dispersion,” IEEE Trans. Wireless Com., vol. 5, no. 2, pp. 417–426, Feb. 2006.Claussen, H., "Performance of Macro- and Co-Channel Femtocells in a Hierarchical Cell Structure," Personal, Indoor and Mobile Radio Communications, 2007. PIMRC 2007. IEEE 18th International Symposium on, pp.1-5, 3-7 Sept. 2007.Kaneko, M.; Popovski, P.; , "Radio Resource Allocation Algorithm for Relay-Aided Cellular OFDMA System," Communications, 2007. ICC '07. IEEE International Conference on , vol., no., pp.4831-4836, 24-28 June 2007.Chandrasekhar, V.; Andrews, J.; "Uplink capacity and interference avoidance for two-tier femtocell networks," Wireless Communications, IEEE Transactions on, vol.8, no.7, pp.3498-3509, July 2009.“The Future of Hotspots: Making Wi-Fi as Secure and Easy to Use as Cellular,” Cisco Whitepaper, http://www.cisco.com/en/US/solutions/collateral/ns341/ns524/ns673/white_paper_c11-649337.html