Co-operating antennas

A new technique which enables mobile phone network cells to change shape according to demand will eliminate the need for more masts to be erected and increase network capacity, say researchers at Queen Mary, University of London.

The UK is covered by several networks of cellular radio antennas that provide coverage for mobile phones.

Antennas are mounted either on freestanding masts or on existing structures and buildings, and use radio signals similar to those used in TV and radio broadcasting. Calls pass through these antennas as people use mobile phones within their areas of coverage.

Mobile phone operators split their networks into defined interlocking areas of coverage, known as ‘cells’. At present the size of each cell is geographically fixed, so that during periods of peak demand the maximum simultaneous call capacity of each cell may not be sufficient to meet customer demand.

This can result in a ‘Network Busy’ or ‘Call Failed’ message on customers’ handsets. Periods of peak demand typically occur at rush hour, Friday evenings and immediately after major sporting events.

Researchers at Queen Mary’s Department of Electronic Engineering have developed new technology called Co-operating Smart Antennas, which allows the dividing line between two cells to be moved to change the sizes of the cells, so leading to more calls being accommodated.

For example, if a cell becomes overloaded with calls at the end of a football match, the system can identify the least busy neighbouring cell and temporarily change the location of the boundary between the two, thereby increasing the network capacity in that area.

Professor Laurie Cuthbert, leading the research, said: ‘Erecting more mobile phone masts won’t solve the problem of overloaded mobile phone networks. We must make better use of the masts we already have. The consumer would benefit from Co-operating Smart Antennas because there would be fewer ‘dropped’ calls, and the benefits to mobile phone companies would include less lost revenue and increased customer satisfaction.’