US 5,943,322 A · Communications method for a code division multiple access system without a base station

Abstract

Personal communications in a code division multiple access system operated without a base is provided with simultaneous transmission of a communications channel and a control channel, each spread by different PN codes. The PN code facilitates restricting communications on the network to a particular conversation mode and between identified radios. Transmissions are performed in a time division duplex manner in 62.5 milliseconds slots. One of the radios initiates transmission and maintains power control and time synchronization normally done by a base station. A network control station can voluntarily or by command transfer control of the network to any of the other radios on the network. Colliding transmissions from more than one radio require the radios to retry transmitting until one of the radios transmits in an earlier time slot. Conversational mode capability is provided by equipping the radio receivers with despreaders in parallel for permitting a receiving radio to separately despread the simultaneously transmitted signals all other radios on the network and responding to each radio transmission individually. Simultaneous voice and data communications can be accomplished by equipping the receivers with despreaders for discriminating voice and data information signals spread by different PN codes.

Claims20

Dependent claims

In a method for communicating by multiple subscribers in a code division multiple access system without a base station, each of said multiple subscribers transmitting communication information modulated by a PN code through an information channel, in combination therewith the improvement comprising the additional steps of:

simultaneously transmitting with said communication information control information through a control channel, from an initiating subscriber, for selectively controlling communications between said multiple subscribers;
and,
modulating said control information by another PN code.

A method for providing personal communications for a network of radios in a code division multiple access system operating without a base station, comprising the steps of:

transmitting control information spread by a PN code through a control channel simultaneously with communications information spread by another PN code through a communications channel;
identifying said network and at least one of said radios using said control channel PN code and restricting said personal communications between said radios of said network using said another PN code;
performing transmit/receive operations of said communications information and said control information by each of said radios in a time division duplexing manner;
controlling said network initially by one of said radios, acting as a network control station for maintaining power control and time synchronization over said network;
and,
transferring control by one of said radios as said network control station to another of said radios to become said network control station for continuing said power control and said time synchronization over said network.

3 more elements

A method for providing personal communications for a network of radios in a code division multiple access system operating without a base station by means of simultaneously transmitting communications information through a communications channel with control information through a control channel, between at least two radios, comprising the steps of:

spreading the transmission of each of said communication information through said communications channel and control information through said control channel with different PN codes to enable restricting said personal communications between at least two of said radios, each of said different PN codes being capable of identifying said network and at least one of said radios;
performing transmit and receive operations by each of said radios in a time division duplex manner with discrete time slots;
controlling said network by one of said radios, acting as a network control station for setting said network control station in a transmit mode and all other of said radios in a receive mode in the first of said discrete time slots;
operating in a transmit mode by said network control station and operating in a receive mode by all other of said radios in the second of said discrete time slots for transmitting said communications information through said communications channel and control channel;
responding by one of said radios with a push-to-talk signal to said communications information and control information transmitted by said network control station;
and,
responding by said network control station to said push-to-talk signal with said control channel for indicating the type of conversation mode for further communications between said network control station and said one of said radios.

4 more elements

Dependencies are inferred from the claim text.

Communications method for a code division multiple access system without a base station

Life of this patent

Communications method for a code division multiple access system without a base station

Life of this patent

Abstract

Claims20