| 摘要 |
In order to improve carry to interference ratios on the down link in mobile communications networks, it is proposed to transmit on the down link in a beam steered at the base station towards the mobile terminal. In order to do that it is necessary to know in which direction the mobile terminal is located. There is disclosed a method of ascribing a direction to the location of a mobile terminal from an antenna array. A sequence of symbols from each antenna 2 in the array, is stored. The sequence contains a known training sequence. The sequence is space processed iteratively so as to produce the effect of the array having a major lobe in its polar diagram at a plurality of different successive directions. A set of crosscorrelation metrics is derived by calculating a crosscorrelation metric for each direction between the combined signals and the known training sequence. The ratio is calculated of the crosscorrelation metric for each direction to the power of the combined signals for that direction to produce a set of direction metrics. A direction is ascribed to the mobile terminal using the direction metrics to determine which direction is most likely.
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