Iwics Inc.

Salbu Research and Development (proprietary) Limited

Salbu Research and Development (proprietary) Limited of Pretoria

Mark Sievert Larsen

James David Larsen

Gerhard Willem Van Lochem

David Victor Larsen

The invention relates to a method of operating a communication network, the network comprising a plurality of stations which are able to transmit data to and receive data from one another. The method comprises monitoring, at each station, the transmission path quality between that station and each other station with which that station can communicate. Data corresponding to the monitored path quality is recorded at each station, thereby permitting a transmission power value based on the relevant path quality data to be selected when transmitting data to another station. Thus, the probability of transmitting data to any selected station at an optimum power level is increased. Each station transmits path quality data in its own transmissions as well as local noise/interference data, so that other stations can obtain path quality data for a particular station even if they are out of range of that particular station. The invention extends to communication apparatus which can be used to implement the method.

Power adaption in a multi-station network

A packet radio network comprises at least one network operator station and a number of user stations. The user stations transmit message data to one another, either directly or via intermediate stations. When stations are first activated, they transmit key request messages to the network operator station. Other, authenticated stations in the network will not communicate with the new station, but will pass the key request message to the network operator station. The network operator station transmits the necessary keys back to the new station via the other stations to permit the new station to operate. Each user station transmits key probe signals from time to time which advise other stations of its public key.

Secure packet radio network

An adaptive communication system utilises opportunistic peak-mode transmissions to transmit data between originating and destination stations, via one or more intermediate stations. Each station monitors the activity of other stations in the network, storing connectivity information for use in subsequent transmissions. Each station also sends out probe signals from time to time, to establish which other stations are in range. Messages are then sent across the network from station to station, with confirmation data being transmitted back to the originating station, until the destination station is reached. Old messages, which would otherwise clog the network, are timed out and deleted. A communication network and transceiver apparatus for use in the network are also disclosed.

Multi-hop packet radio networks

The invention provides a method of operating a communication network. The network comprises numerous stations, each of which can transmit and receive data in order to transmit messages from originating stations to destination stations opportunistically via intermediate stations. Each station selects one of a number of possible calling channels to transmit probe signals to other stations. The probe signals contain data identifying the station in question and include details of its connectivity to other stations. Other stations receiving the probe signals respond directly or indirectly, thereby indicating both to the probing station and other stations their availability as destination or intermediate stations. The probing station evaluates the direct or indirect responses to identify other stations with which it can communicate optimally. For example, the stations may monitor the cumulative power required to reach another station, thereby defining a power gradient to the other stations, with stations selecting a route through the network which optimizes the power gradient. Thus, data throughput through the network is maximized with minimum interference and contention between stations.

Method of operation of a multi-station network

A cellular network comprises a plurality of mobile stations and a plurality of base stations. The base stations are located so that each base station has a zone of effective coverage which does not overlap with the zones of effective coverage of adjacent base stations leaving zones of reduced coverage between the base stations. When a sender station which is outside the zone of effective coverage of a particular base station wishes to send a message to that base station, the message is relayed by another mobile station to the destination base station. The relaying station may be located within the zone of effective coverage, or in the zone of reduced coverage of the destination base station. The sender station, the destination station and the relaying station(s) can all be mobile stations located in zones of reduced coverage. In the zones of reduced coverage, resources such as transmission power, transmission time-slots and frequency channels are utilized on a reduced basis, effectively sharing the resources between the stations.

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Val-de-Grace, South Africa

Mark Sievert Larsen