CDMA mobile communications system and communication method
AssigneeHitachi, Ltd.
InventorsHironari Masui, Yasuo Ohgoshi, Takashi Yano, Nobukazu Doi
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Abstract
A radio communication system having a base station and a plurality of radio terminals, wherein each radio terminal having a transmission request transmits a reservation packet at arbitrary timing through a reservation channel in accordance with a CDMA scheme, and the base station assigns a traffic channel and a time slot to be used to each radio terminal requesting a reservation through a reply packet outputted onto a reply channel. On the reservation channel, a short spreading code corresponding to a matched filter is applied.
Claims17
A communication method in a code division multiple access (CDMA) mobile communication system wherein radio channels between a base station and a plurality of mobile stations include a plurality of traffic channels used for transmitting upward data packets directed from the mobile terminals to the base station and for transmitting downward data packets directed from the base station to the mobile terminals, a reservation channel used for transmitting reservation packets each indicative of a traffic channel assignment request from a mobile terminal to the base station, and a reply channel used for transmitting reply packets each indicative of a traffic channel through which data is to be transmitted and received from the base station to a mobile terminal, and said reservation, reply and traffic channels are assigned unique spreading codes, respectively, said method comprising the steps of:
- transmitting a reservation packet from a mobile terminal having a request for data transmission onto said reservation channel at arbitrary timing;
- transmitting a reply packet onto said reply channel from the base station to specify a traffic channel and a time slot to be used to each mobile terminal which has transmitted said reservation packet;
- and
- transmitting a data packet from each mobile terminal which has transmitted said reservation packet in the specified time slot on the traffic channel specified by said reply packet.
A communication method in a radio communication system wherein a base station and a plurality of radio terminals communicate through a reservation channel, a reply channel and a plurality of traffic channels formed in accordance with a code division multiple access (CDMA) scheme in radio channels, said method comprising the steps of:
- transmitting reservation packets onto said reservation channel from said respective radio terminals requesting data transmission asynchronously with each other;
- after separating a plurality of reservation packet signals having partially overlapped portions on a time axis, received through said reservation channel, corresponding to reservation packets, and performing a receiving process on the reservation packets, transmitting from said base station a reply packet for specifying a traffic channel and a time slot to be used to each radio terminal which is a source of each received reservation packet through said reply channel;
- and
- transmitting a data packet in a specified time slot on a traffic channel specified by said reply packet from said each radio terminal.
A radio terminal apparatus for communicating with a base station through radio channels comprising:
- means for transmitting a reservation packet processed with a spreading code unique to a reservation channel to said base station asynchronously with said base station;
- means for receiving a reply packet processed with a spreading code unique to a reply channel, transmitted from said base station at predetermined time slot timing synchronized with said base station;
- and
- means for transmitting and receiving a data packet processed with a spreading code unique to a particular traffic channel at predetermined time slot timing on said particular traffic channel specified by said reply packet.
A base station for communicating with a plurality of radio terminals, each having a unique address, using spread-spectrum packets through a reservation channel, a reply channel and a plurality of traffic channels, each of said channels corresponded to a unique spreading code, comprising:
- means for receiving reservation packet signals each for requesting a traffic channel access transmitted by the plurality of radio terminals asynchronously with each other through said reservation channel, and separating said reservation packet signals into individual reservation packets for a receiving process;
- means for transmitting through said reply channel a reply packet for specifying a traffic channel and a time slot to be used to a radio terminal which is a source of said reservation packet;
- and
- means for receiving a data packet transmitted from a radio terminal or for transmitting a data packet to a radio terminal in each time slot on a traffic channel.
A mobile communication system comprising a base station and a plurality of mobile terminals, radio channels between the base station and the plurality of mobile terminals comprising a plurality of traffic channels used for transmitting upward data packets directed from mobile terminals to a base station and for transmitting downward data packets directed from the base station to the mobile terminals, a reservation channel used for transmitting reservation packets each indicative of a traffic channel assignment request from a mobile terminal to the base station, and a reply channel used for transmitting reply packets each indicative of a traffic channel through which data is transmitted and received from the base station to a mobile terminal, each of said reservation, reply and traffic channels being assigned a unique spreading code in accordance with a code division multiple access (CDMA) scheme, wherein:
- said each radio terminal comprises first means for transmitting a reservation packet onto said reservation channel at arbitrary timing when a request for data transmission is issued, and a second means for transmitting and receiving a data packet in a time slot specified by a reply packet transmitted from the base station through said reply channel;
- and
- said base station comprises first means for separating a plurality of reservation packet signals having partially overlapped portions on a time axis, received through said reservation channel, into reservation packets and performing a receiving process on said reservation packets, and fourth means for transmitting a reply packet for specifying a traffic channel and a time slot to be used, through said reply channel, to each radio terminal which is a source of each received reservation packet.
Dependencies are inferred from the claim text.