Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE credits
This work studies a TDMA cellular system that divides downlink resources between single users and users sharing a high speed connection. The shared high speed connection is more precisely a Multiple-Input Multiple-Output (MIMO) link between the base station and a mobile relay.
In an attempt to increase cellular system capacity a channel-aware scheduling algorithm -proportional fair is implemented. This algoritm exploits multi-user diversity gains inherited in cellular systems and in scenarios with few antenna elements in the shared MIMO link, this technique is beneficial.
As multiple transmit and receive antennas are added to base station and to relay, antenna-diversity gains is shown to be superior to the multi-user diversity gains obtained by channel-aware scheduling.
Channel-aware scheduling also suffers from channel tracking problems in the investigated scenario and it is found that for a channel quality information feedback delay of 4 ms, a bus speed of 36 km/h reduce the actual capacity gain to zero compared to round robin scheduling.
The option of using several antennas in the shared link reduces the gain from channel-aware scheduling to the point where round robin and MIMO constitute the best feasible solution to increase cellular capacity.