Access method, mobile station and base station for CDMA mobile communication system

A base station communicating with a plurality of mobile stations, said base station comprising:

• (a) a receiver (31) for establishing a common channel with said mobile stations to receive data therefrom, said common channel being defined with at least one access channel and at least one message channel,
• said access channel being used to receive message data of a size smaller than a certain value and a request for transmitting message data of a size larger than said certain value, said request including information regarding the size of said larger message data to be received, and
• said message channel being used to receive said larger message data;
• (b) A traffic controller (32) for determining in response to said request a timing to transmit said larger message data, based on the size of said larger message and a traffic condition on said message channel;
• and
• (c) a transmitter (31) for establishing a broadcast channel with said mobile stations to advise said mobile station of said determined timing.

A mobile station communicating with a base station, said mobile station comprising:

• (a) a receiver (51) for establishing a broadcast channel with said base station to receive a timing to transmit message data of a size larger than a certain value;
• and
• (b) a transmitter (51) for establishing a common channel with said base station to transmit data thereto, said common channel being defined with at least one access channel and at least one message channel,
• said access channel being used to transmit message data of a size smaller than said certain value and a request for transmitting said larger message data, said request including information regarding the size of said larger message data to be transmitted, and
• said message channel being used to transmit said larger message data at said timing received from said base station.

A multiple-access method for a CDMA mobile communication system having a common channel through which a plurality of mobile stations transmit data to a base station and a broadcast channel through which said base station transmits data to said mobile stations, said common channel being defined with at least one access channel and at least one message channel, said multiple-access method comprising the steps of:

• (a) detecting a traffic condition on said access channel;
• (b) determining, based on said detected traffic condition, a probability that one mobile station can transmit data through said access channel without a collision with other data from another mobile station;
• (c) generating a random number at each of mobile stations that have message data to be transmitted through said message channel;
• (d) separating said mobile stations that have said message data to be transmitted into a first group and a second group according to whether their random numbers are larger or smaller than said probability;
• (e) halting the mobile stations in said first group for a certain period of time and then moving back to said step (c);
• (f) allowing the mobile stations in said second group to transmit, through said access channel, a request to transmit said message data;
• (g) determining at said base station timings for the mobile stations in said second group to transmit their message data;
• (h) advising the mobile stations in said second group of the determined timings through said broadcast channel;
• and
• (i) transmitting said message data at said determined timings from the mobile stations in said second group to said base station through said message channel.

A multiple-access method for controlling communication among a plurality of stations sharing at least one communication channel, said method comprising the steps of:

• (a) detecting a traffic condition on said communication channel;
• (b) determining, based on said detected traffic condition, a probability that one station can transmit data through said communication channel without a collision with other data from another station;
• (c) generating a random number at each of stations that have data to be transmitted through said communication channel;
• (d) separating said stations that have data to be transmitted into a first group and a second group according to whether their random numbers are larger or smaller than said probability;
• (e) halting the stations in said first group for a certain period of time and then moving back to said step (c);
• and
• (f) allowing the stations in said second group to transmit the data through said communication channel.