Joint scheduling and resource allocation in CDMA systems

Vijay G. Subramanian, Randall A. Berry, Rajeev Agrawal

Research output: Contribution to journalArticlepeer-review

31 Scopus citations

Abstract

In this paper, the scheduling and resource allocation problem for the downlink in a code-division multiple access (CDMA)-based wireless network is considered. The problem is to select a subset of the users for transmission and for each of the users selected, to choose the modulation and coding scheme, transmission power, and number of codes used. We refer to this combination as the physical layer operating point (PLOP). Each PLOP consumes different amounts of code and power resources. The resource allocation task is to pick the optimal PLOP taking into account both system-wide and individual user resource constraints that can arise in a practical system. This problem is tackled as part of a utility maximization problem framed in earlier papers that includes both scheduling and resource allocation. In this setting, the problem reduces to maximizing the weighted throughput over the state-dependent downlink capacity region while taking into account the system-wide and individual user constraints. This problem is studied for the downlink of a Gaussian broadcast channel with orthogonal CDMA transmissions. This results in a tractable convex optimization problem. A dual formulation is used to obtain several key structural properties. By exploiting this structure, algorithms are developed to find the optimal solution with geometric convergence.

Original languageEnglish (US)
Article number26
Pages (from-to)2416-2432
Number of pages17
JournalIEEE Transactions on Information Theory
Volume56
Issue number5
DOIs
StatePublished - May 2010

Keywords

  • Cellular network
  • Channel-aware scheduling
  • Code-division multiple access (CDMA)
  • Convex optimization
  • Resource allocation
  • Utility maximization

ASJC Scopus subject areas

  • Information Systems
  • Computer Science Applications
  • Library and Information Sciences

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