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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. Contents of the Presentation . LTE Features LTE-A Relaying
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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
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
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
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
Resource Allocation Methodologies • Full Reuse, Isolated Reuse, Grouped Reuse • Reuse 1 at RN • Reuse 3 at RN • Grouped Reuse (GR): GR/R1 GR/R3
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)
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
Inter-Cell Interference Coordination with Grouped Reuse • Reduced interference
End-to-End Throughput per UE • GR/R3 based E2E Resource Allocation in RECs • - • 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
UE Transmit Power • Significant UE battery savings with GR/R3 REC
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.
Thank you! Questions? …