CTH03-5: Optimal Resource Allocation via Geometric Programming for OFDM Broadcast and Multiple Access Channels

Abstract

For multi-user orthogonal frequency division multiplexing (OFDM) systems, efficient optimal rate and power allocation algorithms are presented via geometric programming (GP), a special form of convex optimization problem for which very efficient interior point methods exist. Both multiple access channel (MAC) and broadcast channel (BC) are considered and the following two resource allocation problems are of main interest: weighted sum-rate maximization (WSRmax) and weighted sum-power minimization (WSPmin). Utilizing degradedness of BC on each tone, WSRmax and WSPmin in the BC can be all formulated as GP. By using the duality relation between MAC and BC, it is shown that the above resource allocation problems in the MAC can be converted into GP problems as well. This GP perspective of multi-user OFDM resource allocation problems provides numerical efficiency as well as strong scalability for any additional constraints of GP form.