Efficient allocation of CQI channels in broadband wireless networks

In an OFDMA network, the modulation and coding scheme (MCS) of the messages sent to the mobile stations (MSs) varies according to channel condition. To determine the appropriate MCS level, the base station (BS) allocates to every active MS a CQI (Channel Quality Information) channel. The CQI bandwidth is a scarce resource whose allocation must be adjusted to the actual needs of the MSs. However, allocations and deallocations of CQI channels require expensive signaling messages between the BS and the MSs, and therefore should be minimized. In this paper we propose a framework for the management of the CQI bandwidth by the BS. We identify three related optimization problems and propose efficient algorithms for solving them.