Distributed Routing Schemes with Accessibility Consideration in Multi-Hop Wireless Networks

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

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

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) up N1 T … … N2 S D down • 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

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