© DTG DTG Investigations Into Wireless Distribution of Broadband in Homes WLAN Advisory Group Meeting 5 th November 2002 Will Dobbie, DML Chairman of the DTG WHN Group

© DTG DTG Wireless Home Networks Group DTG is a UK based Industry Group aimed at implementing Digital TV systems It actively contributes to the DVB standards The WHN group has around 50 members and is currently progressing: DVB WHN standards for 5GHz bands A and B based on IEEE802.11a++ and HIPERLAN 2 A new standard for Digital Video Senders operating in band C - the 5.8GHz ISM band

© DTG Case for Wireless Home Networks WHN’s avoid the need for new wires and allow delivery to portable terminals Important for analogue switch-over because DTT cannot reach all set-top antennas Also desirable for provision of multiple simultaneous broadband sessions everywhere WLAN based systems will eventually evolve to become practical for the mass-market DVS approach is more practical for asymmetric services near term – replace analogue at 2.4GHz

© DTG DVS - PROFILE 1 DVB-T Receiver Main TV Rx + D/C 2nd TV DVB-T Receiver Tuner + U/C RC Diversity Antenna Broadcast Channel Control Channel More complex profiles will include a gateway for other asymmetric TV or data services

© DTG DVS Forward Channel Based on MPEG2 via DVB-T/COFDM Channel bandwidth c.8MHz Compatible with low cost consumer receivers Channels monitored at receiver – free channel selected via control channel (inc simple DFS?) TPC set to allow a reasonable margin at the furthest terminal i.e. minimum power used Optimum back-off still TBD

© DTG Spectrum / Interference Issues Preliminary tests show 25mW e.i.r.p. should be sufficient in many cases Higher power (50-100mW?) would increase coverage in worst cases – further tests planned Interference from FWA due to leakage through windows etc. is a major concern Need frequency sharing studies to ensure WHN applications are not made impractical FWA will steadily migrate to higher frequencies as demand for bandwidth/QOS increases