MULTI-USER UP-LINK RELAY SHARING OVERVIEW AND DESIGN EXAMPLES
Bo Zhang
Jun 13th, 2014
Overview
Backgrounds
System Model
Up-Link Relay Sharing Design
Design Examples
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Bo Zhang, CSPC Group, School of ECS, Uni. of Southampton 14-Jun-14 2
Backgrounds: Cellular Networks
Bo Zhang, CSPC Group, School of ECS, Uni. of Southampton 14-Jun-14 3
Backgrounds: Wireless Sensor Networks
Bo Zhang, CSPC Group, School of ECS, Uni. of Southampton 14-Jun-14 4
System Model
Topology Dual-Hop
M-1-1 Nodes
W/O Direct Links
Channel Block Rayleigh Fading
Single Antenna Nodes
Path-loss Exponent >2
14-Jun-14 Bo Zhang, CSPC Group, School of ECS, Uni. of Southampton 5
Up-Link Relay Sharing Design (1)
Bo Zhang, CSPC Group, School of ECS, Uni. of Southampton 14-Jun-14 6
Medium Access Control
Relay Receive
Processing
Relay Transmit
Processing
Destination Processing
Design Objective/Evaluations Reliability Metrics
Outage Probability, Bit/Symbol/Frame Error-Ratio
Rate Metrics Capacity, Throughput
Complexity Metrics Others
Up-Link Relay Sharing Design (2)
Bo Zhang, CSPC Group, School of ECS, Uni. of Southampton 14-Jun-14 7
Medium Access Control
Relay Receive
Processing
Relay Transmit
Processing
Destination Processing
Link/Hop Activation Fixed Link Activation Dynamic Hop Activation Dynamic Link Activation
SN-RN Hop Access Control Orthogonal Division Multiple Access
TDMA/FDMA/CDMA Multi-user Diversity
Non-Orthogonal Division Multiple Access SDMA/IDMA/Non-orthogonal CDMA
Up-Link Relay Sharing Design (3)
Bo Zhang, CSPC Group, School of ECS, Uni. of Southampton 14-Jun-14 8
Medium Access Control
Relay Receive
Processing
Relay Transmit
Processing
Destination Processing
Non-Regenerative Methods Amplify-and-Forward Detect-and-Forward
Regenerative Methods Decode-and-Forward Compress-and-Forward
F. Gomez-Cuba, et.al. “A survey on cooperative diversity for wireless networks” IEEE Commun. Surv. Tutorials, Sep. 2011.
Up-Link Relay Sharing Design (4)
Bo Zhang, CSPC Group, School of ECS, Uni. of Southampton 14-Jun-14 9
Medium Access Control
Relay Receive
Processing
Relay Transmit
Processing
Destination Processing
Orthogonal Division Multiplexing Keep the transmission rate
Increasing the transmission rate
Superposition-based Multiplexing Finite-Field-NC:
(b1 + b2 + b3 + ...) mod(N) -> Modulation
SuperPosition Modulation: Modulation -> (s1 + s2 + s3 + .... )/Pt
Up-Link Relay Sharing Design (5)
Bo Zhang, CSPC Group, School of ECS, Uni. of Southampton 14-Jun-14 10
Medium Access Control
Relay Receive
Processing
Relay Transmit
Processing
Destination Processing
Relying on the previous three choices.
Single User Detection Process each user’s signal separately
Multiple User Detection Process each user’s signal jointly
Maximum likelihood detection
Successive/parallel interference cancellation
Others
Medium Access Control
Relay Receive
Processing
Relay Transmit
Processing
Destination Processing
14-Jun-14 Bo Zhang, CSPC Group, School of ECS, Uni. of Southampton 11
Design Example A
Medium Access Control TDMA with equal time allocation Fixed link activation
Relay Receive Processing Decode-and-Forward
Relay Transmit Processing A: Use M Relaying TSs B: Use 1 SPM Relaying TS
14-Jun-14 Bo Zhang, CSPC Group, School of ECS, Uni. of Southampton 12
Design Example A
Conventional Scheme 2M TSs to transmit M SNs’ messages Spectrum Efficiency = 1/2 Equivalent cluster size M = 1
Superposition Modulated (SPM) (M+1) TSs to transmit all messages Spectrum Efficiency = M/(M+1) SE increases with M
Medium Access Control
Relay Receive
Processing
Relay Transmit
Processing
Destination Processing
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Design Example A: Destination Processing
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Design Example A: Performance Analysis
Design Example A: Performance Evaluation
For arbitrary number of sources, a single relaying phase may offer a diversity of 2.
The “NC noise” would increase with the number of sources.
The comparison may not be fair due to different spectrum efficiency.
14-Jun-14 Bo Zhang, CSPC Group, School of ECS, Uni. of Southampton 15
Design Example A: Performance Evaluation
Consider equal end-to-end transmission rate per source, the SPM scheme using less time slots does not always win.
SPM schemes are less sensitive to relay position deployments.
14-Jun-14 Bo Zhang, CSPC Group, School of ECS, Uni. of Southampton 16
Design Example A: Performance Evaluation
Example of M = 5 Sources.
The worst uplink dominates the outage performance.
14-Jun-14 Bo Zhang, CSPC Group, School of ECS, Uni. of Southampton 17
It seems “a bigger source cluster” improves the spectral efficiency by relay sharing.
But NOT always. Even though we assume perfect channel estimation (CE).
The destination processing in SPM scheme is more sensitive to CE.
When sharing a relay, the designer should choose the partner sources wisely Sources Clustering
Other techniques to mitigate NC noise
14-Jun-14 Bo Zhang, CSPC Group, School of ECS, Uni. of Southampton 18
Design Example A: Take-Away
Presented work: S. Sharma, Y. Shi, J. Liu, Y. T. Hou, S. Kompella, and S. F. Midkiff, “Network coding in cooperative communications: friend or foe?,” IEEE Trans. Mob. Comput., vol. 11, no. 7, pp. 1073–1085, Jul. 2012.
B. Zhang, J. Hu, Y. Huang, M. El-Hajjar and L. Hanzo. Outage Analysis of Superposition Modulation Aided Network Coded Cooperation in the Presence of Network Coding Noise. IEEE Trans. Veh. Technol. [Accepted]
Source clustering: S. Sharma, Y. Shi, Y. Hou, H. Sherali, and S. Kompella, “Optimizing network-coded cooperative communications via joint session grouping and relay node selection,” in Proceedings of the conference on Information communications (INFOCOM), 2011, pp. 1898–1906.
Z. Mobini, P. Sadeghi, M. Khabbazian, and S. Zokaei, “Power allocation and group assignment for reducing network coding noise in multi-unicast wireless systems,” IEEE Trans. Veh. Technol., vol. 61, no. 8, pp. 3615–3629, Oct. 2012
14-Jun-14 Bo Zhang, CSPC Group, School of ECS, Uni. of Southampton 19
Design Example A: Relevant Contributions
Medium Access Control
Relay Receive
Processing
Relay Transmit
Processing
Destination Processing
14-Jun-14 Bo Zhang, CSPC Group, School of ECS, Uni. of Southampton 20
Design Example B: Preview
Medium Access Control TDMA with Equal Time Allocation Dynamic Hop Activation SN-RN Hop SDMA
Relay Receive Processing Decode-and-Forward
Relay Transmit Processing Time Division Multiplexing
A ONCE PROMISING Technique “Cooperative communications paradigms such as cooperative multipoint or relaying, which despite falling short of their initial hype are nonetheless beneficial, could require a redefinition of the functions of the different nodes.”
Full-duplex Relaying
Massive Multiple-Input-Multiple-Output Techniques
Smaller Cells/Device Centric Networks
F. Boccardi, R. W. Heath, A. Lozano, T. L. Marzetta, and P. Popovski, “Five disruptive technology directions for 5G,” IEEE Commun. Mag., vol. 52, no. 2, pp. 74–80, Feb. 2014.
“Five Disruptive Technology Directions for 5G”
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