'Institute of Electrical and Electronics Engineers (IEEE)'
Doi
Abstract
We study the problem of multiple packet bundling
to improve spectral efficiency in cellular networks. The packet
size of real-time data, such as VoIP, is often very small. However,
the common use of time division multiplexing limits the number
of VoIP users supported, because a packet has to wait until it
receives a time slot, and if only one small VoIP packet is placed
in a time slot, capacity is wasted. Packet bundling can alleviate
such a problem by sharing a time slot among multiple users. A
recent revision of cdma2000 1xEV-DO introduced the concept
of the multi-user packet (MUP) in the downlink to overcome
limitations on the number of time slots. However, the efficacy
of packet bundling is not well understood, particularly in the
presence of time varying channels. We propose a novel QoS and
channel-aware packet bundling algorithm that takes advantage
of adaptive modulation and coding. We show that optimal
algorithms are NP-complete, recommend heuristic approaches,
and use analytical performance modeling to show the gains
in capacity that can be achieved from our packet bundling
algorithms. We show that channel utilization can be significantly
increased by slightly delaying some real-time packets within their
QoS requirements while bundling those packets with like channel
conditions. We validate our study through extensive OPNET
simulations with a complete EV-DO implementation.Supported in part by U.S. National Science Foundation under grant no. 072971
