Two-Relay-Based Cooperative MAC Protocol for Wireless Ad hoc Networks

Murad Khalid, Yufeng Wang, In-ho Ra, and Ravi SankarUniversity of South FloridaIEEE Transactions On Vehicular Technology, VOL. 60, NO. 7, SEPTEMBER 2011Two-Relay-Based Cooperative MAC Protocolfor Wireless Ad hoc Networks1OutlineIntroductionGoal2rcMAC protocolSimulationConclusion

IntroductionThe cooperative communication approach effective uses of spatial diversity in wireless ad hoc networksImproved throughput Delay performance

60s20s20sRelated WorkCoopMAC I

Its performance deteriorates under fading conditions due to lower direct path or relay path reliability4Related WorkUTD MAC

Not fully benet from higher throughput relay path (compared with the direct path) since it uses relay path only as a secondary backup path5GoalWe propose a 2rcMAC protocolBetter transmission reliabilityHigher throughput through the relay pathHigher performance under fast-fading conditionsSystem Model2rcMAC protocolSingle-channel / Single-hop ad hoc networkMultiple data rates of 1, 2, 5.5, and 11 Mb/sControl packets and headers are transmitted at 1 Mb/s

71Mbps2Mbps11Mbps5.5Mbps2Mbps2rcMAC protocol

1Mbps2Mbps11Mbps

5.5Mbps2MbpsDSr1r22rcMAC protocolRR frameEight-slot frame7 bits per slot

S

D

RTSCTS

92rcMAC protocolThe source node searches for the two best relayStart from the (11,11) rate categoryTotal transmission time

First best relaySecond best relay

102rcMAC protocolFour casesTwo best relaysOnly one best relayNo best relayNo relay feedback

2rcMAC protocolMAC headerOnly one relayPick RelayNAV Adaptation

12SimulationParameterValueFrequency2.4 GHzMAC header272 bitsPHY header192 bitsRTS/CTS/ACK160 bits/112 bits/112 bitsSlots time20 usSIFS/DIFS10 us/50 usPayload1023 bytesCWmax/CWmin1024/32Rate for MAC, PHY header, RTS, CTS, ACK packtes 1MbpsSIMULATION PARAMENTERSSimulation

14Simulation

15Simulation

Simulation

17Thank You