A fast transmit power control based on Markov transition for DS-CDMA mobile radio

Hirohito Suda, Hiroyuki Kawai, Shinichi Sasaki, Fumiyuki Adachi

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

In direct sequence code division multi-access (DS-CDMA) mobile radio, closed-loop fast transmit power control (TPC) must be sufficiently fast to track fast multipath fading. However, in urban areas, the line-of-sight (LOS) path may appear abruptly when a mobile station comes out from behind a building and later suddenly the LOS may disappear, resulting in an abrupt path-loss change in the order of 30 to 40 dB. This "on-off" path loss change can be considered as a special case of shadowing. This rapid shadowing causes two problems at the base station: generation of large multiaccess interference (MAI) to other users when the LOS path appears and degradation in the quality of its own signal when the LOS path disappears. A new closed-loop fast TPC based on Markov-state transitions (called Markov fast TPC) is proposed. State transition is determined by the past history of the received binary TPC commands sent from the base station. The TPC step size is associated with the state. By changing the step size between as small as 0.8 dB and as large as 4 dB, the Markov fast TPC can better track rapid shadowing as well as multipath fading compared to conventional one-state closed-loop fast TPC. The TPC error is evaluated by computer simulation to demonstrate the adaptability of the proposed Markov fast TPC in a Rayleigh fading channel superimposed by LOS.

Original languageEnglish
Title of host publicationICUPC 1998 - IEEE 1998 International Conference on Universal Personal Communications, Conference Proceedings
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages235-239
Number of pages5
ISBN (Electronic)0780351061, 9780780351066
DOIs
Publication statusPublished - 1998 Jan 1
Externally publishedYes
EventIEEE International Conference on Universal Personal Communications, ICUPC 1998 - Florence, Italy
Duration: 1998 Oct 51998 Oct 9

Publication series

NameICUPC 1998 - IEEE 1998 International Conference on Universal Personal Communications, Conference Proceedings
Volume1

Other

OtherIEEE International Conference on Universal Personal Communications, ICUPC 1998
CountryItaly
CityFlorence
Period98/10/598/10/9

Keywords

  • Base stations
  • Degradation
  • Fading
  • Land mobile radio
  • Multiaccess communication
  • Multiple access interference
  • Power control
  • Shadow mapping
  • Signal generators
  • Urban areas

ASJC Scopus subject areas

  • Computer Networks and Communications

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  • Cite this

    Suda, H., Kawai, H., Sasaki, S., & Adachi, F. (1998). A fast transmit power control based on Markov transition for DS-CDMA mobile radio. In ICUPC 1998 - IEEE 1998 International Conference on Universal Personal Communications, Conference Proceedings (pp. 235-239). [732833] (ICUPC 1998 - IEEE 1998 International Conference on Universal Personal Communications, Conference Proceedings; Vol. 1). Institute of Electrical and Electronics Engineers Inc.. https://doi.org/10.1109/ICUPC.1998.732833