mizing fairness and meeting QoS requirements. This method is generally used in communications systems that are relatively reliable (i.e., have a low bit error ratio (BER)), and where all users have a simi- lar, unchanging connection. However, this approach is more difficult if channel conditions are worse or vary with time, frequency, and/or location. The reason for this is that schedul- ing transmissions in the future cannot be guaranteed: the channel may have changed, or retransmissions may be necessary. This section begins with a description of traditional wire- line scheduling algorithms, such as for Asynchronous Transfer Mode (ATM) networks, fol- lowed by a discussion of various adaptations of these algorithms for wireless networks. All traffic is not created equal: some traffic types are more susceptible to certain network degradations than others. For example, some traffic may be very sensitive to delay, while other traffic may be more vulnerable to overall network throughput. A connection-oriented network such as ATM attempts to allow for these different traffic types by implementing mul- tiple service categories. Depending on their requirements, different scheduling algorithms may be chosen for different service categories. These algorithms can generally be separated into two categories: priority-based and fair-share schedulers. Priority-based schedulers man- age traffic from different queues according to some defined priority criteria. Lower priority traffic is transmitted after higher priority traffic. In contrast, fair-share schedulers attempt to distribute bandwidth among the different traffic types such that some notion of fairness is preserved. Various scheduling algorithms falling into either of these two scheduler catego- ries, such as the earliest deadline first (EDF) algorithm, or the Round-Robin (RR) algorithm, are summarized by Giroux and Ganti.² It is assumed that the reader is familiar with these basic types of scheduling algorithms. Most research published on the topic of QoS scheduling is