Jointly opportunistic beamforming and scheduling (JOBS) for downlink packet access

Opportunistic scheduling (OS) has been proposed as a technique to improve the downlink throughput of high speed packet systems. OS attempts to use the time varying propagation channels between the base station (BS) and the mobile stations (MSs) when they reach their peak rate capability and defer using channels when in bad state. It exploits the fact that the propagation channels between the BS and the MSs fade independently and the tolerance of many data services to delay and delay jitter. However, when the fading is slow in comparison with an acceptable packet delay, or weak, OS is not very useful. In such cases, opportunistic beamforming (OBF), a recently proposed scheme, may offer additional gains. OBF is a "natural" enhancement to OS. The enhancement amounts to replacing the BS antenna with multiple antennas and implementing an algorithm that generates a different radiation pattern every timeslot. In this paper we propose to tie the sequence of radiation patterns to the waiting times of the served MSs. We show through simulations that the scheme we propose leads to both, reduced probability of excessive packet delay and improved throughput. This can be achieved by additional processing of the feedback received from the MSs, with no additional signaling on the air interface.