We present a simple uplink access technique for packet data communications in a mobile environment. This technique is an application of a random-access communication scheme with slotted ALOHA to a wireless cellular system. All base stations connected to a control station use a common frequency and have synchronized slots. Mobile terminals can transmit packets at any time and do not require slot reservation, handover control, or transmission power control. This system can perform base station diversity reception with selective combining or with maximal ratio combining (MRC) in the uplink. Computer simulation shows that throughput is much improved when base stations use adaptive array antennas. In addition, the effects of the limitation of retransmissions on throughput and service fairness for all mobile terminals are analyzed.
['Makoto Yamada', 'Yoshitaka Hara', 'Yukiyoshi Kamio', 'Sliinsuke Hara']
Packet communications with slotted ALOHA in a mobile cellular system