MULTI-USER UP-LINK RELAY SHARING OVERVIEW AND DESIGN EXAMPLES

Bo Zhang

bz2g10@ecs.soton.ac.uk

Jun 13th, 2014

Overview

Backgrounds

System Model

Up-Link Relay Sharing Design

Design Examples

More Ingredients

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

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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

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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

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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.

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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.

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Design Example A: Performance Evaluation

Example of M = 5 Sources.

The worst uplink dominates the outage performance.

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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

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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

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Design Example A: Relevant Contributions

Medium Access Control

Relay Receive

Processing

Relay Transmit

Processing

Destination Processing

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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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