Throughput versus fairness: channel-aware scheduling in multiple antenna downlink
EURASIP Journal on Wireless Communications and Networking - Special issue on fairness in radio resource management for wireless networks
Data dissemination in wireless broadcast channels: network coding versus cooperation
IEEE Transactions on Wireless Communications
The rate region of a cooperative scheduling system
IEEE Transactions on Wireless Communications
Optimized opportunistic multicast scheduling (OMS) over wireless cellular networks
IEEE Transactions on Wireless Communications
Effective capacity maximization in multi-antenna channels with covariance feedback
ICC'09 Proceedings of the 2009 IEEE international conference on Communications
Effective capacity maximization in multi-antenna channels with covariance feedback
IEEE Transactions on Wireless Communications
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We consider a single-antenna broadcast block fading channel with n users where the transmission is packet- based. We define the (packet) delay as the minimum number of channel uses that guarantees all n users successfully receive m packets. This is a more stringent notion of delay than average delay and is the worst case (access) delay among the users. A delay optimal scheduling scheme, such as round-robin, achieves the delay of mn. For the opportunistic scheduling (which is throughput optimal) where the transmitter sends the packet to the user with the best channel conditions at each channel use, we derive the mean and variance of the delay for any m and n. For large n and in a homogeneous network, it is proved that the expected delay in receiving one packet by all the receivers scales as nlogn, as opposed to n for the round-robin scheduling. We also show that when m grows faster than (log n)r, for some r > 1, then the delay scales as mn. This roughly determines the time- scale required for the system to behave fairly in a homogeneous network. We then propose a scheme to significantly reduce the delay at the expense of a small throughput hit. We further look into the advantage of multiple transmit antennas on the delay. For a system with M antennas in the transmitter where at each channel use packets are sent to M different users, we obtain the expected delay in receiving one packet by all the users.