MVDS and cable-modulation and coding for efficient spectrum utilisation

In the United Kingdom, TV delivery by cable has been very slow to develop. An important contributory factor is the cost of cable laying. In the future, so called 'technology neutral' licences will allow local delivery operators to choose the transmission medium. Microwave video distribution service (MVDS) may be a cheaper solution but it can only compete with cable if it is capable of delivering 20-30 channels. The upper half of the 12 GHz band, 12.1-12.5 GHz is under consideration in the UK for MVDS, but with only 400 MHz of bandwidth available, the number of channels available is limited. The 40 GHz band, 40.5-42.5 GHz has already been allocated by the UK government for MVDS, and with 2 GHz of spectrum available it might appear to be ideal. In practice the coverage area achievable in this band is limited and more power efficient modulation schemes are required. Consideration must be given not only to cable and NVDS individually but also to hybrid cable/MVDS systems. In this paper modulation methods for cable and MVDS are discussed. The possibility of a common modulation method for hybrid cable/MVDS systems is also considered.