Time Delay Compensation for CDMA Power Control
2000 (English)Report (Other academic)
Transmission power control is essential in CDMA systems in order to reduce the near-far effect and to optimize the bandwidth utilization, which is critical when variable data rates are used. One remaining problem is oscillations in the output powers due to round-trip delays in the power control loops together with the power up-down command device. The oscillations are naturally quantified using discrete-time describing functions, which are introduced and applied. More importantly, Time Delay Compensation (TDC) is proposed to mitigate the oscillations. It is also formally proven that TDC result in a stable overall system, with power control errors that converges to a defined bounded region. These bounds are tighter, compared to when not employing TDC. Simulations illustrate the oscillations and the significant performance gains using TDC.
Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2000. , 5 p.
LiTH-ISY-R, ISSN 1400-3902 ; 2287
Power control, Cellular radio systems, Time delays, Time delay compensation, Discrete-time describing functions, Convergence
National CategoryControl Engineering
IdentifiersURN: urn:nbn:se:liu:diva-55742ISRN: LiTH-ISY-R-2287OAI: oai:DiVA.org:liu-55742DiVA: diva2:316590