1. Distributed Routing Schemes with Accessibility Consideration in Multi-Hop Wireless Networks Presented By Junghwi, Jeon 2010/02/01

2. Reference  Distributed Routing Schemes with Accessibility Consideration in Multi-Hop Wireless Networks IEEE Transactions on Wireless Communications, October, 2010 Authors  Weiwei Wang, Jun Cai and Attahiru S. Alfa  University of Manitoba, Canada Networking and Distributed Systems Lab., POSTECH

3. Introduction  Two objectives in routing Optimizing the system performance Maximizing the accessibility  Previous methods Optimal and table-driven methods  Significant signaling overhead Distributed routing methods  Trade-off between link state and number of hops  e.g. Most Forward within Radius (MFR) scheme, Largest Link Rate (LLR) scheme Networking and Distributed Systems Lab., POSTECH

4. Goal  To design routing scheme that can balance the trade-off between system performance and accessibility Networking and Distributed Systems Lab., POSTECH

5. System Model  System structure Assumption  Each node knows its own position, its one-hop neighbors position and the destination position Information Moving Distance (IMD) : Information Jumping Distance (IJD) : Networking and Distributed Systems Lab., POSTECH

6. System Model (cont’d)  Channel model OFDM and Adaptive Modulation and Coding (AMC)  SNR  Link capacity  Network spectral efficiency Equal-Time Bandwidth Sharing : transmit power : an exponential distribution : shadowing with lognormal distribution : distance of a link : path loss exponent Networking and Distributed Systems Lab., POSTECH

7. System Model (cont’d)  Problem formulation Networking and Distributed Systems Lab., POSTECH : the set of all possible routes : the objective function ( )

8. Adaptive-Information-Moving-Distance- and-Link-Rate scheme (AIMDLR)  Objective function Max-min problem is NP-hard problem To relax to be a problem,  Select the receiver at the each hop IMD > & link spectral efficiency > Otherwise, maximizing ( ) x ( ) Networking and Distributed Systems Lab., POSTECH

9. Probability-based AIMDLR (1/2)  Accessibility if we consider only IMD, this scheme may result in the destination becoming unreachable Probability Based Scheme (PBS)  Candidate nodes are divided into two group (up, down)  N1 and N2 have the largest information moving rate in up and down, respectively ( )  Select the better node in terms of  There are 2 cases Networking and Distributed Systems Lab., POSTECH up down T SD N1 N2 ……

10. Probability-based AIMDLR (2/2)  Case 1 : & N2 ( or & N1) is set to be one  Case 2 : & N1 ( or & N2) A quadratic equation in  Two solution  Only the one in [0,1] is reasonable  Both of them are in [0,1] : the larger value  None of them is in [0,1] : zero  One solution  equals the solution of it is in [0,1]; otherwise, is set to be zero  No solution  is set to zero Networking and Distributed Systems Lab., POSTECH

11. Conclusion  Distributed routing scheme Considering one-hop available information and one S- D pair in the network  balancing the trade-off between the accessibility and the system performance System performance  Network spectral efficiency under ETBS Accessibility  PBS Networking and Distributed Systems Lab., POSTECH