Throughput Optimization in Multi-hop Wireless Networks with Random Access

Wireless Networks;Cross-layer Optimization;Throughput;Medium Access Control;Routing;Network Coding;Electrical and Computer Engineering

Uddin, Md. Forkan

University of Waterloo

关键词: Wireless Networks;    Cross-layer Optimization;    Throughput;    Medium Access Control;    Routing;    Network Coding;    Electrical and Computer Engineering;   

Others  :  https://uwspace.uwaterloo.ca/bitstream/10012/5947/1/Uddin_Md.%20Forkan.pdf

瑞士|英语

来源: UWSPACE Waterloo Institutional Repository

【 摘 要 】

This research investigates cross-layer design in multi-hop wireless networks withrandom access. Due to the complexity of the problem, we study cross-layer designwith a simple slotted ALOHA medium access control (MAC) protocol without considering any network dynamics. Firstly, we study the optimal joint configuration of routing and MAC parameters in slotted ALOHA based wireless networks under a signal to interference plus noise ratio based physical interference model. We formulate ajoint routing and MAC (JRM) optimization problem under a saturation assumptionto determine the optimal max-min throughput of the flows and the optimal configuration of routing and MAC parameters. The JRM optimization problem is a complexnon-convex problem. We solve it by an iterated optimal search (IOS) technique andvalidate our model via simulation. Via numerical and simulation results, we showthat JRM design provides a significant throughput gain over a default configurationin a slotted ALOHA based wireless network.Next, we study the optimal joint configuration of routing, MAC, and networkcoding in wireless mesh networks using an XOR-like network coding without opportunistic listening. We reformulate the JRM optimization problem to include thesimple network coding and obtain a more complex non-convex problem. Similar tothe JRM problem, we solve it by the IOS technique and validate our model via simulation. Numerical and simulation results for different networks illustrate that (i) the jointly optimized configuration provides a remarkable throughput gain with respectto a default configuration in a slotted ALOHA system with network coding and (ii)the throughput gain obtained by the simple network coding is significant, especiallyat low transmission power, i.e., the gain obtained by jointly optimizing routing, MAC,and network coding is significant even when compared to an optimized network without network coding. We then show that, in a mesh network, a significant fraction ofthe throughput gain for network coding can be obtained by limiting network codingto nodes directly adjacent to the gateway.Next, we propose simple heuristics to configure slotted ALOHA based wirelessnetworks without and with network coding. These heuristics are extensively evaluatedvia simulation and found to be very efficient. We also formulate problems to jointlyconfigure not only the routing and MAC parameters but also the transmission rateparameters in multi-rate slotted ALOHA systems without and with network coding.We compare the performance of multi-rate and single rate systems via numericalresults.We model the energy consumption in terms of slotted ALOHA system parameters.We found out that the energy consumption for various cross-layer systems, i.e., singlerate and multi-rate slotted ALOHA systems without and with network coding, arevery close.