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

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

Introduction  Electromagnetic interference sources at 2.4GHz [1]  WLAN(IEEE b/g)  ZigBee(IEEE )  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) /1/26 2MHz 7MHz [1] Texas Instruments, “The Effects of Adjacent channel Rejection and Adjacent channel interference on WLAN Performance, ” SPLY005-Nov White Paper

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

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

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 (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

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 Link bc Link de Link ef Link gh Link hi Link ad Link be 0Channel 1 Link cf Link dg Link eh Link fi Link12 α(s)= β(c)=1,1,1,1,1,0,0,0,0,0,0, Assign channel ： channel 6 Link12 α(s)= β(c)=1,1,1,1,1,0,0,0,0,0,0, Assign channel ： channel /1/ ch1 a c b d f e g i h Link ab α(s)= β(c)=1,1,1,1,1,0,0,0,0,0,0 Assign channel ： channel 6 Link ab α(s)= β(c)=1,1,1,1,1,0,0,0,0,0,0 Assign channel ： channel 6 ch6 channel 6

Summary and Objective  Greedy algorithm  Flexible to allocate channel in large WMNs  No consideration about: radio load balance partially overlapping Interference 8 MAP 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

 Objectives  balance the radio traffic load  reduce multi-radio interference by conflict graph Channel Assignment Strategy - FPOC 9 STA MAP MAP a c b d f e g i h radio link Traffic 2016/1/26

radio 1 radio 2 link eb : 39 link eh : 38 link ba : 29 MAP e link ef : Node order of assignment : FPOC Channel Assignment Strategy a b c d e f g h i 2016/1/26 OrderMAPOrder factor 1e1206 2b h564 4d426 5f420 6a c i234 9g193.5 assigned link eb : 39 link eh : 38 link ed : 29 assigned link ef : 28

11 Conflict Graph FPOC Channel Assignment Strategy 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

FPOC Channel Assignment Strategy 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 /1/26 LinkSet1 LinkSet2 LinkSet6 LinkSet5 LinkSet4 LinkSet3

Simulations  Parameters in NS-2 simulator  b, 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

Simulation Results /1/26

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 /1/26