Cluster-Adaptive Two-Phase Coding Multi-Channel MAC Protocol (CA-TPCMMP) for MANETs 1 Lili Zhang, 1 Boon-Hee Soong, and 2 Wendong Xiao 1 School of Electrical & Electronic Engineering Nanyang Technological University 2 Institute for Infocomm Research, Singapore IEEE International Conference on Communications (ICC), 2005

Outline Introduction Introduction CA-TPCMMP CA-TPCMMP Simulations Simulations Conclusions Conclusions

Introduction The basic criterion of code assignment is that the same codes are reused more than two hops away The basic criterion of code assignment is that the same codes are reused more than two hops away This kind of assumption leads to expensive communication overhead This kind of assumption leads to expensive communication overhead

Motivation Alleviate the heavy control overhead in a MANET Alleviate the heavy control overhead in a MANET –Through clustering

CA-TPCMMP Two phase coding Two phase coding –For collision avoidance Multi-channel Multi-channel –One control channel –One data channel

Two-phase coding 1 st phase code: for differentiating adjacent clusters 1 st phase code: for differentiating adjacent clusters 2 nd phase code: for distinguishing the nodes in a specific cluster 2 nd phase code: for distinguishing the nodes in a specific cluster

CA-TPCMMP 1 st phase codes 1 st phase codes 2 nd phase codes 2 nd phase codes A transmission code is defined as A transmission code is defined as C(i): set of nodes of cluster i C(i): set of nodes of cluster i NeiCh1(i): set of neighbor clusters of cluster i NeiCh1(i): set of neighbor clusters of cluster i

Code confliction (1) –

Code confliction (2) If, it requires to ensure If, it requires to ensure

Code confliction (3) For any node if there exists a cluster k such that For any node if there exists a cluster k such that

Access mechanism of control channel M1: available # of frames can be used for the adjacent clusters M2: supported # of CMs in a cluster BS: beacon slot MS: maintenance slot RFS: request for slot COS: confirm of slot

Usage of maintenance slots Used by the CMs for Used by the CMs for –maintaining clusters –Negotiating the appropriate first-phase codes –Allocating the second-phase codes

A CH candidate becomes a CH itself 1.Listen for a duration of a superframe 2.choose a random 1 st code CH sends probing message in Beacon slot Receives opposition (broadcasting) from CM? No Use current 1 st code Update 1 st code according to opposition

First-phase code confliction (1) If S i < S j If S i < S j i will re-compete for its 1 st phase code i will re-compete for its 1 st phase code

First-phase code confliction (2) If S h < S i < S j If S h < S i < S j h, j re-compete for their 1 st phase codes h, j re-compete for their 1 st phase codes

First-phase code confliction (3) If S h < S i < S j If S h < S i < S j h, j re-compete for their 1 st phase codes h, j re-compete for their 1 st phase codes

Selection of 2nd phase code A CH maintains it available code set (ACS) A CH maintains it available code set (ACS) CM transmits a RFS by marking the code request field CM transmits a RFS by marking the code request field CH allocates a code by transmitting a COF CH allocates a code by transmitting a COF Acknowledge is make by broadcasting Acknowledge is make by broadcasting

Simulation environment simulator NS-2 with CMU extension topology 1000m x 1000m Nodes # 100 traffic 30 random flows, UDP, 512 B/ P Propagation model 2-ray ground Routing protocol AODV Mobility model Random waypoint speed20m/s Data channel 2Mbps Control channel 0.3Mbps Protocol parameter : M1 20 Protocol parameter : M2 mean + standard deviation of the # of CMs within CH’s range

Avg. control overhead vs. transmission range

Avg. control overhead vs. avg. speed

Conclusions CA-TPCMMP CA-TPCMMP –seamlessly integrates 2-phase coding scheme with dynamic clustering –Mitigates the hidden terminal problem during data transmission

Thank you!!