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Uplink Resource Allocation in LTE-A

Relay Enhanced Cellular Networks

Master’s Thesis Seminar

Presented by:Anzil Abdul Rasheed

Master’s Program – Radio Communications

Thesis Supervisor:Prof. Jyri Hämäläinen

25.03.2009

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Contents of the Presentation LTE Features LTE-A Relaying Simulation Parameters Resource Allocation Methodologies Performance Analysis CDFs

SINR Throughput Inter-Cell Interference Coordination End-to-End Throughput UE Transmit Power

Conclusions

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LTE Features Support for scalable bandwidth

1.25, 1.6, 2.5, 5, 10, 15 and 20 MHz Improved data rates

For a 20 MHz spectrum allocation UL – 50 Mbps, DL – 100 Mbps

Support for mobility upto 350 km/h All IP-based flat network architecture Reduced latency Reduced operator maintenance costs Multi-layer security OFDMA & SC-FDMA based transmission scheme

Reduced interference Robust to multipath

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LTE-A Relaying

DF RNs are foreseen as one of the means to satisfy the performance targets of 4G networks as defined by ITU-R

Advantages: Improved radio quality in shadowed/high path-loss regions Easier upgrade from current deployments Self backhauling

Reduced costs in data tunneling (ref. HeNB) Improved security (independence)

Reduced CAPEX/OPEX Challenges:

Maintain simple architecture Interference related issues from a new RAP Multihop transmission delays Resource allocation

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Simulation Parameters

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Resource Allocation Methodologies Full Reuse, Isolated Reuse, Grouped Reuse

Reuse 1 at RN Reuse 3 at RN

Grouped Reuse (GR): GR/R1 GR/R3

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CDF of SINR per PRB

@ eNB Full Reuse increases interference Isolated Reuse prevents interference between the direct and access links

Throughput gain needs to be seen! Grouped Reuse performs well and improves SINR over the eNB-only deployment

Interference from access link transmissions is under control @ RN

SINR improvement in all cases as expected Reuse 3 is beneficial (as expected) for reducing interference among RNs

Indirect benefit in the form of reduced interference at eNB (for FR and GR)

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CDF of Throughput per UE

•FR and IR do not improve throughput of all UEs• GR translates to improved throughput

• Gains from complete resource allocation for eNB

•GR performs the best

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Inter-Cell Interference Coordination with Grouped Reuse

•Reduced interference

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End-to-End Throughput per UE GR/R3 based E2E Resource Allocation in RECs

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•Relay link is an overhead in REC system design•With well-coordinated resource allocation such as GR/R3, REC can outperform conventional eNB-only system

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UE Transmit Power

•Significant UE battery savings with GR/R3 REC

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Conclusions Resource allocation is a critical factor in improving the

multi-hop performance GR/R3 is an efficient resource allocation methodology

Achieves interference coordination High spectral efficiency

The relay link is a bottleneck in system design Resource allocation for relay link is an issue with multiple RNs

deployed per sector Realizing performance gains with in-band RN deployment is

challenging, but achievable with a well-designed transmission scheme and system parameter settings.

A UE operating in a REC (especially GR/R3 based) can experience significantly improved battery life.

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Thank you!

Questions? …