Frame (eg UMTS TDD-CDMA) including pilots scattered throughout the payload in addition to midamble pilot sequence for fast fading channel

摘要

A normal UMTS TDD-CDMA (Universal Mobile Telephone System Time Division Duplex-Code Division Multiple Access) frame 600 includes a midamble 610 comprising a pilot sequence 635 and cyclic prefix 630 for the purpose of synchronisation and channel estimation. This is adequate for static/slow fading channels. The invention adds further pilot symbols 650 scattered amongst the payload data symbols 625/640. This hybrid pilot arrangement improves channel estimation and hence signal detection in fast fading conditions. The invention estimates the channel using the midamble pilot only and performs data detection. The detected additional pilot symbols and possibly the midamble pilot symbols are then used to perform a further channel estimation and this is used to correct the amplitude and phase of the payload data symbols detected previously. The additional pilots may be single symbols.