Title :
Cross-Layer Designs in Coded Wireless Fading Networks With Multicast
Author :
Rajawat, Ketan ; Gatsis, Nikolaos ; Giannakis, Georgios B.
Author_Institution :
Dept. of Electr. & Comput. Eng., Univ. of Minnesota, Minneapolis, MN, USA
Abstract :
A cross-layer design along with an optimal resource allocation framework is formulated for wireless fading networks, where the nodes are allowed to perform network coding. The aim is to jointly optimize end-to-end transport-layer rates, network code design variables, broadcast link flows, link capacities, average power consumption, and short-term power allocation policies. As in the routing paradigm where nodes simply forward packets, the cross-layer optimization problem with network coding is nonconvex in general. It is proved, however, that with network coding, dual decomposition for multicast is optimal so long as the fading at each wireless link is a continuous random variable. This lends itself to provably convergent subgradient algorithms, which not only admit a layered-architecture interpretation, but also optimally integrate network coding in the protocol stack. The dual algorithm is also paired with a scheme that yields near-optimal network design variables, namely multicast end-to-end rates, network code design quantities, flows over the broadcast links, link capacities, and average power consumption. Finally, an asynchronous subgradient method is developed, whereby the dual updates at the physical layer can be affordably performed with a certain delay with respect to the resource allocation tasks in upper layers. This attractive feature is motivated by the complexity of the physical-layer subproblem and is an adaptation of the subgradient method suitable for network control.
Keywords :
broadcast channels; fading channels; gradient methods; multicast communication; network coding; optimisation; power consumption; protocols; radio links; radio networks; resource allocation; telecommunication network routing; asynchronous subgradient method; average power consumption; broadcast link flows; broadcast links; coded wireless fading networks; continuous random variable; cross-layer designs; cross-layer optimization problem; dual algorithm; dual decomposition; dual updates; end-to-end transport-layer rates; layered-architecture interpretation; link capacity; multicast end-to-end rates; near-optimal network design variables; network code design quantity; network code design variables; network coding; network control; optimal resource allocation framework; physical layer; physical-layer subproblem; protocol stack; provably convergent subgradient algorithms; resource allocation tasks; routing paradigm; short-term power allocation policy; wireless link; Fading; Interference; Network coding; Optimization; Resource management; Signal to noise ratio; Wireless communication; Asynchronous subgradient methods; cross-layer designs; multihop; network coding; optimization methods;
Journal_Title :
Networking, IEEE/ACM Transactions on
DOI :
10.1109/TNET.2011.2109010