1. FPOC: A Channel Assignment Strategy using Four Partially Overlapping Channels in Mid-scale Wireless Mesh Networks Broadband Mobile Wireless Networks Lab. Y.C.Lin, C.H.Lin, W.S.Hwang, and C.K.Shieh Department of Electrical Engineering National Kaohsiung University of Applied Sciences and National Cheng Kung University

2. Outline 2 Introduction Related Work FPOC Channel Assignment Strategy Conclusions Simulation Results 2016/1/26

3. Introduction  Electromagnetic interference sources at 2.4GHz [1]  WLAN(IEEE 802.11b/g)  ZigBee(IEEE 802.15.4)  Wireless Phones, and so on.  Wireless interference  Co-channel interference  Adjacent Channel Interference (ACI) Non-overlapping channel Partially Overlapping Channels (POC) –Channel separation(chsp) of 3 and 4 ( Arunesh Mishra, University of Maryland) 3 2016/1/26 2MHz 7MHz [1] Texas Instruments, “The Effects of Adjacent channel Rejection and Adjacent channel interference on 802.11 WLAN Performance, ” SPLY005-Nov. 2003 White Paper

4. Adjacent Channel Interference  Overlap factor (olf) [2]  Overlapped area size of two separated channels 4 [2] Mitch Burton(Cirond Technologies), “Channel Overlap Calculations for 802.11b Networks, ” White Paper, Nov. 2002. Channel:1 、 6 、 11 Overlap factor:0.0008 Channel:1 、 5 、 9 、 13 Overlap factor:0.0054 Channel:1 、 4 、 7 、 10 Overlap factor:0.0375 2016/1/26

5. Scenario2 Scenario1 A B C D Ch4 Ch8 Ch11 Problem Statement 5 A B C D Ch1 Ch6 Ch1 Ch11 Scenario1Scenario2 Channels Ch1.6.1.11Ch1.4.8.11 Dropping rate47.8%20.6% Ch1 Table I Dropping Rate 2016/1/26

6. Related Work 6  Greedy algorithm[3]  IF(Interference Factor)  Interference Range  Interference Free –Distance is over double of transmission range(R) –Channel separation(chsp) is 5 [3] Yong Ding, “Channel Assignment with Partially Overlapping Channels in Wireless Mesh Networks, ” WICON 2008 and ICST 2008. (Michigan State University) Link2 Link1 Distance 2016/1/26 (a) Bit Rate =2M(b) Bit Rate =5.5M (c) Bit Rate =11M chsp0chsp1chsp2chsp3chsp4chsp5 2M2R1.125R0.75R0.375R0.125R0 5.5M2RR0.625R0.375R0.125R0 11M2RR0.5R0.375R0.125R0

7. Related Work 7  Greedy algorithm [3]  Step I – Select Calculate α(s) for each link that has not been assigned channel  Step II – Assign Calaulate β(c) for each channel that has minimum α(s) Linkα(s)Channel Link ab 3.719 Link bc 3.719 Link de 6.0661 Link ef 6.0661 Link gh 6.7934 Link hi 6.7934 Link ad 5.1487 Link be 0Channel 1 Link cf 5.1487 Link dg 6.2645 Link eh 6.7934 Link fi 6.2645 Link12 α(s)= 3.719 β(c)=1,1,1,1,1,0,0,0,0,0,0, Assign channel ： channel 6 Link12 α(s)= 3.719 β(c)=1,1,1,1,1,0,0,0,0,0,0, Assign channel ： channel 6 2016/1/26 17 19 27 29 28 26 16 39 38 19 23 ch1 a c b d f e g i h Link ab α(s)= 3.719 β(c)=1,1,1,1,1,0,0,0,0,0,0 Assign channel ： channel 6 Link ab α(s)= 3.719 β(c)=1,1,1,1,1,0,0,0,0,0,0 Assign channel ： channel 6 ch6 channel 6

8. Summary and Objective  Greedy algorithm  Flexible to allocate channel in large WMNs  No consideration about: radio load balance partially overlapping Interference 8 MAP 17 19 27 29 28 26 16 39 38 19 23 MAP ch1 ch3 ch2 ch11 ch8 ch1 ch7 ch10 ch6 ch8 MAP Interference Load Balance 2016/1/26 a c b d f e g i h

9.  Objectives  balance the radio traffic load  reduce multi-radio interference by conflict graph Channel Assignment Strategy - FPOC 9 STA MAP 17 19 27 29 28 26 16 39 38 19 23 MAP a c b d f e g i h radio link Traffic 2016/1/26

10. radio 1 radio 2 link eb : 39 link eh : 38 link ba : 29 MAP e link ef : 28 10 Node order of assignment : FPOC Channel Assignment Strategy 17 19 27 29 28 26 16 39 38 19 23 a b c d e f g h i 2016/1/26 OrderMAPOrder factor 1e1206 2b1012.5 3h564 4d426 5f420 6a290.25 7c256.5 8i234 9g193.5 assigned link eb : 39 link eh : 38 link ed : 29 assigned link ef : 28

11. 11 Conflict Graph FPOC Channel Assignment Strategy 17 19 27 29 28 26 16 39 38 19 23 a b c d e f g h i Link set1 Link set2 Link set4 Link set5 Link set3 Link set6 2016/1/26 LinkSet1 LinkSet2 LinkSet6 LinkSet5 LinkSet4 LinkSet3

12. 12 2 5 4 1 3 FPOC Channel Assignment Strategy 17 19 27 29 28 26 16 39 38 19 23 a b c d e f g h i TrafficConflict-freeChannels LinkSet167null LinkSet267null LinkSet456LinkSet3 LinkSet542LinkSet6 42LinkSet5 LinkSet336LinkSet4 Channel 4 Channel 1 Channel 8 Channel 11 Channel 8 2016/1/26 LinkSet1 LinkSet2 LinkSet6 LinkSet5 LinkSet4 LinkSet3

13. Simulations  Parameters in NS-2 simulator  802.11b, data rate 1 Mbps, 2 radios/node  Transceiver range: 200 m / Interference range: 400 m  Available channel: 4 13 Transmission Range Interference Range 2016/1/26 a b c d e f g h i j k l m n o p q r s t u v w x y

14. Simulation Results 14 2016/1/26

15. Conclusions  Wireless LAN is popular, and more APs are used in a limit space.  In mid-scale wireless mesh networks, its performance is largely affected by number of available channels.  This paper proposed  Four less interference partially overlapping channels to work  A channel assignment strategy with Balance radio load Channel interference  Get better throughput and dropping rate 15 2016/1/26