Multiple antennae solve mobile web access

High-speed wireless data transfer could be achieved with a system of multiple antennae, researchers at Motorola claim.

Following experiments in urban areas where data was transmitted to and from laptops and PDAs, the company said rates of 20 megabits/sec were possible. This is much faster than existing 3G phone transmission. DoCoMo’s 3G service, due to be launched in Japan this week, transmits at 384 kilobits/sec.

The technology could make possible many of the promised 3G mobile phone multimedia services, such as video transmission, and full internet access. Theoretical work by Motorola suggested that multiple antennae could enable major increases in data capacity, similar to cable broadband levels.

However, the actual performance could have been somewhat lower due to environmental issues and interference. Due to signals being bounced between buildings and other features of the landscape true data rates might be a little lower.Tests were needed to understand the effects of the urban environment and the capacity limits that could be achieved.

With the multiple antennae system the constituent parts of the video or multimedia data to be transmitted is sent from a number of different antennae.

The signals are then received by a similar number of antennae. Each signal has a tag that identifies the antenna which sent it. This prevents the receiving device from being overwhelmed by any replicated data.

The tests proved that the level of 20megabits/sec was a top speed for data transfer using this system.

Dennis Roberson, Motorola’s chief technology officer, said wireless bandwidth is a major issue for the telecoms industry.

‘We and others are working on various approaches in order to determine optimum standards and system requirements. but one thing is certain – the technology really needs to deliver higher data rates to the consumer at a lower cost per data bit,’ he said.

The test results are to be used in simulations that will model the signal processing in the wireless devices and base stations. That work will produce more predictions for the actual capacity users can expect to get. The results could mean changes to wireless standards as early as this autumn to aid the technology’s development.

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