Overload control in a packet-switching cellular environment

This invention relates to cellular telephony and, more particularly, to the use of packet techniques in cellular telephony. An improved cellular arrangement is created with mobile units that are responsive to control signals that direct the mobile units to modify the rate of packet transmissions in case of channel overload. A mobile unit in such an arrangement encodes either the speech signal, or only a portion thereof that is sufficient to reproduce a lower fidelity speech which is still intelligible-and at a lower rate. In another embodiment, the mobile unit creates a second stream of packets, also at a lower rate. The second stream complements the first stream of packets in its lower rate form, to allow reproducing the speech signal with high fidelity. Operationally, such a mobile unit is responsive to a base station which, under overload conditions, directs the mobile unit to transmit packets at the lower rate (and the lower fidelity). Optionally, the base station can also directs the mobile unit to send the second stream of packets over a different channel.