European 900 MHz analogue standard

Date: 2015-10-07; view: 448.

Another body of opinion in Europe took a somewhat longer view of the potential of cordlessness, in terms of its potential demand on radio spectrum when the number of cordless terminals exceeded about 10% of normal wired terminals. This vision resulted in the following standard, that has been adopted in most CEPT affiliated countries, with the exception of the UK and France who chose the h. f/v. h. f. option that offered a significantly lower production cost. The CEPT standard has the following general characteristics:

1. Analogue FM operation.

2. Forty 25 kHz duplex channels in the frequency bands 914-915 MHz paired with 959-960 MHz.

3. Radiated power limited to 10mW.

4. Dynamic channel selection (DCS) on call set up.

This last feature sets араrt this standard from the earlier technol­ogy. On call set up either from a base (incoming call) or handset (outgoing call) all forty channels are scanned in order to select a vacant radio channel, or one where the co-channel interference is acceptable low, on which to set up the telephone call.

This feature has a complexity burden but results in all users being able to use any available radio channel. Therefore spectrum efficiency in terms of traffic carried per megahertz per square kilometre is very much increased compared to a factory set single channel system of the type considered in the last section. The benefits of DCS shows when the total cordless traffic demand in a localised area is such that co-channel interference from other users becomes the dominating factor in terms of speech quality and range of operation.

Technically the CEPT standard is a major step forward in cordless product design but is consequently more expensive than the far simpler h. f. /v. h. f. analogue design. It has, therefore, not achieved the degree of market penetration throughout Europe as its proposers had originally predicted.