Title :
Cell selection based on shadowing variation for forward link broadband OFCDM packet wireless access
Author :
Morimoto, Akihito ; Abeta, Sadayuki ; Sawahashi, Mamoru
Author_Institution :
Wireless Labs., NTT DoCoMo Inc., Kanagawa, Japan
Abstract :
This paper proposes cell (sector) selection based on shadowing variation for forward-link orthogonal frequency and code division multiplexing (OFCDM) packet wireless access. We clarify its effects using a broadband propagation channel model in a comparison with fast cell selection (FCS) which tracks the fading variation and conventional cell selection (CS) utilizing the distance-dependent path loss, based on radio link level simulations that take into account instantaneous fading and shadowing variations. The simulation results clarify that the achievable throughput with FCS improves slightly in a broadband channel with an increasing number of paths when the average path-loss difference between two cells is greater than 2 dB. Nevertheless, we elucidate that the optimum CS interval equals that for tracking the shadowing variation, i.e., approximately 100 msec considering high mobility, caused by reducing the degradation in throughput when the cell with lower received power is selected, which suffers from shadowing variation. Consequently, we show that the average throughput by employing CS based on shadowing variation with the selection interval of 100 msec is increased by approximately 5 and 15% compared to that with the selection interval of 1 sec, which only tracks distance-dependent path loss, for the maximum Doppler frequency of 20 and 200 Hz, respectively.
Keywords :
3G mobile communication; OFDM modulation; broadband networks; cellular radio; code division multiple access; digital simulation; fading channels; multiuser channels; packet radio networks; radiowave propagation; spread spectrum communication; 3GPP; 3rd Generation Partnership Project; OFCDM; W-CDMA; average path-loss difference; average throughput; broadband channel; broadband packet wireless access; broadband propagation channel model; cell selection; distance-dependent path loss; fading variation; fast cell selection; forward link; maximum Doppler frequency; orthogonal frequency and code division multiplexing; radio link level simulations; received power; selection interval; shadowing variation; simulation results; wideband direct sequence code division multiple access; Bandwidth; Code division multiplexing; Fading; Frequency; Laboratories; Multiaccess communication; OFDM; Radio link; Shadow mapping; Throughput;
Conference_Titel :
Vehicular Technology Conference, 2002. Proceedings. VTC 2002-Fall. 2002 IEEE 56th
Print_ISBN :
0-7803-7467-3
DOI :
10.1109/VETECF.2002.1040583