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.
Original language | English (US) |
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Article number | 5720273 |
Pages (from-to) | 1276-1289 |
Number of pages | 14 |
Journal | IEEE/ACM Transactions on Networking |
Volume | 19 |
Issue number | 5 |
DOIs | |
State | Published - Oct 2011 |
Bibliographical note
Funding Information:Manuscript received February 12, 2010; revised August 20, 2010; accepted December 29, 2010; approved by IEEE/ACM TRANSACTIONS ON NETWORKING Editor S. Shakkottai. Date of publication February 24, 2011; date of current version October 14, 2011. This work was supported by the National Science Foundation (NSF) under Grants CCF-0830480, ECCS-1002180, and ECCS-0824007. Part of this paper has been presented at the 3rd IEEE International Wireless Network Coding Workshop, Boston, MA, June 21, 2010.
Keywords
- Asynchronous subgradient methods
- cross-layer designs
- multihop
- network coding
- optimization methods