By Topic

Delay-optimal power control and performance analysis in SDMA system with limited buffer size via stochastic decomposition

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

2 Author(s)
Liangzhong Ruan ; Dept. of Electr. & Electron. Eng., Hong Kong Univ. of Sci. & Technol., Kowloon, China ; Lau, V.K.N.

In previous study on multi-user delay optimal problem, the exponentially increasing state space become one of the main obstacle. Moreover, packet drop due to finite buffer size is not taken into account. In this paper, we exploit the birth-death dynamics of the buffered SDMA systems and proposed a new approach, namely stochastic decomposition, to derive the delay optimal power adaptation scheme in a SDMA system. Unlike the conventional CSI-only power control solution, the delay-optimal power control has the multi-level water-filling structure in which the QSI determines the water-level and the CSI determines the power allocation across the SDMA users. This new approach overcomes the complexity issue mentioned above and allow us to obtain closed-form performance expressions so as to obtain the following first-order insights: 1) The water-filling levels {1/alphak, q Nmacrk} under different QSIs q isin {1, 2, ...L} is an increasing geometric series. 2) The optimal average delay Umacrk* achieved by the multilevel water filling algorithm is tau/O(log Pmacrk + O(log log Pmacrk) - lambdak while that achieved by traditional CSI-only scheme is tau/O(log Pmacrk) - lambdak. 3) Minimum average power required to satisfy a packet drop rate constraint isind (due to finite buffer) is given by: log log(Pmacrk, min) prop - log isind/L + log (lambdak) + log (Nmacrk).

Published in:

Information Theory, 2009. ISIT 2009. IEEE International Symposium on

Date of Conference:

June 28 2009-July 3 2009