e station for all terminals in the cell, form link adaptation on the long-term average channel a max-C/I scheduler will result in no, or a very low, user quality and rely on hybrid ARQ with soft combining for throughput for users at the cell edge with a low average the rapid adaptation. channel quality. The reason is the fundamental strategy For the uplink, estimation of the uplink channel con- of the max-C/I scheduler - all resources are allocated for ditions is not as straightforward as there is typically not transmission to the terminal whose channel conditions any reference signal transmitted with constant power support the highest data rate. Only in the rare, not to say from each mobile terminal. unlikely, case of a cell-edge user having better conditions In case of a system with time-division duplex (TDD) than a cell-center user, for example due to a deep fading where uplink and downlink communication are time dip for the cell-center user, will the cell-edge user be multiplexed within the same frequency band, the uplink scheduled. A proportional-fair scheduler, on the other signal attenuation could be estimated from downlink hand, will ensure some degree of fairness by selecting the measurements of the mobile terminal, due to the reci- user supporting the highest data rate relative to its av- procity of the multi-path fading in case of TDD. erage data rate. Hence, users tend to be scheduled on However, it should then be noted that this may not their fading peaks, regardless of the absolute quality. provide full knowledge of the downlink channel condi- Thus, users on the cell edge will also be scheduled, tions. As an example, the interference situations at the thereby resulting in (some degree of) fairness between mobile terminal and the base station are different also in users. case of TDD. For a scenario with bursty packet data, the situation is different. In this case, the users' buffers will be finite and in many cases also empty. For example, a web page has 4.5.2.5 Traffic behavior and scheduling a cert