Packet-switched cellular telephone system

A packet-switched cellular telephone system for switching telephone calls between cellular telephones and a landline network and switching data packets between the cellular telephones and a data network, each one of the cellular telephones generating a voice radio channel request to request voice service and generating a packet-mode radio channel request to request data service, comprising:

• a plurality of base sites each including:
• transceiver means having at least one signaling radio channel for receiving the voice radio channel requests and the packet-mode radio channel requests from the cellular telephones, and having voice channels and shared packet-mode radio channels for communications with the cellular telephones, each of the shared packet-mode radio channels capable of being shared by at least two of the cellular telephones;
• and control means responsive to each received voice radio channel request for assigning a requesting one of the cellular telephones to one of the voice radio channels and responsive to each received packet-mode radio channel request for assigning a requesting one of the cellular telephones to one of the shared packet-mode radio channels;
• packet access point means for multiplexing packets from the shared packet-mode radio channels to the data network and demultiplexing packets from the data network to said shared packet-mode radio channels;
• and
• switching means coupled to each of the plurality of base sites for coupling the voice radio channels to the landline network and the shared packet-mode radio channels to said packet access point means.

A method of handoff for use at base sites of a cellular telephone system for handing off from one of the base sites to another one of the base sites at least one of a plurality of cellular telephones each transceiving data packets and sharing a cellular packet-switched radio channel of the cellular telephone system, said method comprising the steps of:

• monitoring the number of inbound packets received from all active ones of the plurality of cellular telephones sharing the cellular packet-switched radio channel to determine an inbound rate of transfer of data packets;
• polling at least one of the active ones of the plurality of cellular telephones when the determined inbound rate of transfer is less than a predetermine inbound rate;
• and
• sending a handoff message to one of the active ones of the plurality of cellular telephones when the polled one of the active ones of the plurality of cellular telephones does not respond.

A method of handoff for use at base sites of a cellular telephone system for handing off from one of the base sites to another one of the base sites at least one of a plurality of cellular telephones each transceiving data packets and sharing a cellular packet-switched radio channel of the cellular telephone system, said method comprising the steps of:

• monitoring errors in data packets received from each active one of the plurality of cellular telephones sharing the cellular packet-switched radio channel to determine a bit-error rate therefor;
• determining the signal strength level of each active one of the plurality of cellular telephones on the cellular packet-switched radio channel;
• and
• sending a handoff message to one of the active ones of the plurality of cellular telephones when the determined signal strength level therefor is less than a predetermined signal strength level and the determined bit-error rate therefor is greater than a predetermined bit-error rate.

A method of handoff for use at base sites of a cellular telephone system for handing off from one of the base sites to another one of the base sites at least one of a plurality of cellular telephone each transceiving data packets and sharing a digital cellular radio channel of the cellular telephone system, said method comprising the steps of:

• monitoring the number of inbound packets received from all active ones of the plurality of cellular telephones sharing the digital cellular radio channel to determine an inbound rate of transfer of data packets;
• polling at least one of the active ones of the plurality of cellular telephones when the determined inbound rate of transfer is less than a predetermine inbound rate;
• and
• sending a handoff message to one of the active ones of the plurality of cellular telephones when the polled one of the active ones of the plurality of cellular telephone does not respond.

A method of handoff for use at base sites of a cellular telephone system for handing off from one of the base sites to another one of the base sites at least one of a plurality of cellular telephones each transceiving data packets and sharing a digital cellular radio channel of the cellular telephone system, said method comprising the steps of:

• monitoring errors in data packets received from each active one of the plurality of cellular telephones sharing the digital cellular radio channel to determine a bit-error rate therefor;
• determining the signal strength level of each active one of the plurality of cellular telephones on the digital cellular radio channel;
• and
• sending a handoff message to one of the active ones of the plurality of cellular telephones when the determined signal strength level therefor is less than a predetermined signal strength level and the determined bit-error rate therefor is greater than a predetermined bit-error rate.