1. Multiple Frequency Reuse Schemes in the Two-hop IEEE 802.16j Wireless Relay Networks with Asymmetrical Topology Weiwei Wang a, Zihua Guo b, Jun Cai c, Xuemin(Sherman) Shen d, Changjia Chen a a School of Electronics and Information Engineering, Beijing Jiaotong University, Beijing, China b Lenovo Cooperate Research, Beijing, China c Department of Electrical and Computer Engineering, University of Manitoba, Winnipeg, Manitoba, Canada d Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, Ontario, Canada to appear in

2. Outline Introduction Motivation Frequency Reuse Schemes –IBFRS –DFPP –SR Simulation Conclusion

3. Introduction Relay-related function is being standardized as the extension to the basic standards, such as IEEE 802.16j. There are generally two advantages brought by Relay Stations in WiMAX : –to overcome the coverage hole of BS and provide ubiquitous wireless services cost-efficiently –to improve network throughput due to possible reuse of radio resources In this paper, throughput performance of the access links (i.e., BS to MS and RS to MS) is analyzed for the two-hop IEEE 802.16j wireless relay networks with asymmetrical topology.

4. Introduction RS in IEEE 802.16j –Transparent RS –Non-transparent RS RS MS BS Transparent RS DL Access Zone (BS to MS or RS) Optional transparent Zone (Silent or BS transmitting) UL Access Zone (MS to BS) UL Relay Zone (BS receiving) DL Access Zone (RS receiving) Optional transparent Zone (RS to MS or RS) UL Access Zone (MS to RS) UL Relay Zone (RS to BS or RS to RS) RS BS

5. Introduction – Transparent RS

6. Introduction RS in IEEE 802.16j –Transparent RS –Non-transparent RS DL Access Zone (BS to MS) DL Relay Zone (BS to RS) UL Access Zone (MS to BS) UL Relay Zone (BS receiving) DL Access Zone (RS to MS) DL Relay Zone (RS to RS or RS receiving) UL Access Zone (MS to RS) UL Relay Zone (RS to BS or RS to RS) RS BS Non-transparent RS BS MS RS Coverage Hole Shadowing Area

7. Introduction – Non-transparent RS - Frequency reuse - MS in BS’s Range MS in RS’s Range

8. Motivation RS in IEEE 802.16j –Transparent RS –Non-transparent RS DL Access Zone (BS to MS) DL Relay Zone (BS to RS) UL Access Zone (MS to BS) UL Relay Zone (BS receiving) DL Access Zone (RS to MS) DL Relay Zone (RS to RS or RS receiving) UL Access Zone (MS to RS) UL Relay Zone (RS to BS or RS to RS) RS BS System Bandwidth = = f BS Isolation Band RS Cluster Reuse-Area

9. Frequency Reuse Scheme – IBFRS - Isolation Band based Frequency Reuse Scheme - S : the total acreage of the cell A BS : the area served by the BS with the acreage of S BS A RSc : the area served by the RS cluster with the acreage of S RSc A nr BS : the isolation band with the acreage of S nr BS A r BS : the area served by the BS but out of the isolation band, which has an acreage of S r BS BS Isolation Band RS Cluster

10. Frequency Reuse Scheme – IBFRS - Isolation Band based Frequency Reuse Scheme - S : the total acreage of the cell A BS : the area served by the BS with the acreage of S BS A RSc : the area served by the RS cluster with the acreage of S RSc A nr BS : the isolation band with the acreage of S nr BS A r BS : the area served by the BS but out of the isolation band, which has an acreage of S r BS BS Isolation Band RS Cluster

11. Frequency Reuse Scheme – IBFRS - Isolation Band based Frequency Reuse Scheme - S : the total acreage of the cell A BS : the area served by the BS with the acreage of S BS A RSc : the area served by the RS cluster with the acreage of S RSc A nr BS : the isolation band with the acreage of S nr BS A r BS : the area served by the BS but out of the isolation band, which has an acreage of S r BS BS Isolation Band RS Cluster

12. Frequency Reuse Scheme – IBFRS - Isolation Band based Frequency Reuse Scheme - S : the total acreage of the cell A BS : the area served by the BS with the acreage of S BS A RSc : the area served by the RS cluster with the acreage of S RSc A nr BS : the isolation band with the acreage of S nr BS A r BS : the area served by the BS but out of the isolation band, which has an acreage of S r BS BS Isolation Band RS Cluster not Reuse-Area

13. Frequency Reuse Scheme – IBFRS - Isolation Band based Frequency Reuse Scheme - S : the total acreage of the cell A BS : the area served by the BS with the acreage of S BS A RSc : the area served by the RS cluster with the acreage of S RSc A nr BS : the isolation band with the acreage of S nr BS A r BS : the area served by the BS but out of the isolation band, which has an acreage of S r BS BS Isolation Band RS Cluster Reuse-Area

14. Frequency Reuse Scheme – IBFRS - Isolation Band based Frequency Reuse Scheme - A BS : the area served by the BS with the acreage of S BS A nr BS : the isolation band with the acreage of S nr BS A r BS : the area served by the BS but out of the isolation band, which has an acreage of S r BS not Reuse-Area Reuse-Area

15. Frequency Reuse Scheme – IBFRS - Isolation Band based Frequency Reuse Scheme - B : system bandwidth C BS : the spectrum efficiency of A BS when no frequency reuse between the BS and the RS cluster (bit/s/Hz) C RSc : the spectrum efficiency of RS cluster (bit/s/Hz) Assume the users are uniformly distributed in A BS.

16. Frequency Reuse Scheme – IBFRS - Isolation Band based Frequency Reuse Scheme - Ө : [0,1] be the decrease of the spectrum efficiency of A r BS after the RSs reuse the frequency from the reuse area. The throughput of A BS, denoted as T BS, is The throughput of A RSc, denoted as T RSc, is not Reuse-Area Reuse-Area System Bandwidth = = f BS

17. Frequency Reuse Scheme – IBFRS - Isolation Band based Frequency Reuse Scheme - BS Isolation Band RS Cluster

18. Frequency Reuse Scheme – IBFRS - Isolation Band based Frequency Reuse Scheme - Assume a location, in A BS of the cell 0 The SINR at is given as : I BS is the set of the interference sources to is the transmitting power of BS in cell d is the path loss from BS in cell d is the shadowing from BS in cell d is the value of the noise in cell 0

19. Frequency Reuse Scheme – IBFRS - Isolation Band based Frequency Reuse Scheme - can be approximated by a lognormal variable with –mean –standard variance C.D.F.

20. Frequency Reuse Scheme – DFPP - Dynamic Frequency Power Partition scheme - The frequency of each RS serving area is divided into two parts –Primary frequency : orthogonal among adjacent RSs and is transmitted by the high power level –Secondary frequency : is transmitted by the low power level PF 1 PF 3 PF 2 PF 1 PF 2 PF 1 SF… System Bandwidth = = f PF k … PF 2 PF 1 RS Cluster

21. Frequency Reuse Scheme – SF - Selective Reuse scheme - Due to the long distance, the sub-channel used by user A may be reused by the RS in the reuse group 2.

22. Simulation Matlab –Carrier frequency : 2.5GHz –System bandwidth : 10MHz –Number of sub-channels : 30 –Number of sub-carriers in a sub-channel : 24 –BS cell radius : 1Km –BS TX Power : 38dBm(high) ; 33dBm(low) –BS pathloss : 138.6+34.79log 10 (d) –RS cell radius : 0.1Km –RS TX Power : 5dBm(high) ; 1dBm(low) –RS pathloss : 143.69+37.2log 10 (d) –Shadowing : mean (0dB) and standard variance (8dB) –Modulation and coding scheme : as the definition in IEEE 802.16e

23. Simulation not Reuse-Area Reuse-Area BS

24. Simulation Tradition : no frequency reuseeach user is allocated one sub-channel

25. Simulation Tradition : no frequency reuseeach user is allocated one sub-channel

26. Simulation Tradition : no frequency reuseeach user is allocated one sub-channel

27. Conclusion In this paper, three frequency reuse schemes for the two-hop relay network based on IEEE 802.16j has been proposed. The simulation results indicate that the proposed IBFRS+DFPP+SR scheme can significantly improve the throughput of the access links with little negative influence to other users served by the BS. Our future work will focus on more complex scenarios, such as networks with directional antennas.

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