<p>Telecommunication systems are under constant development. Currently 3GPP is working on an evolution of the 3G-standard, under the name 3G Long Term Evolution (LTE). Some of the goals are higher throughput and higher peak bit rates. A crucial part to achieve the higher performance is channel dependent scheduling (CDS). CDS is to assign users when they have favorable channel conditions. Channel dependent scheduling demands accurate and timely channel quality reports. These channel quality indication (CQI) reports can possibly take up a large part of the allocated uplink. This thesis report focuses on the potential gains from channel dependent scheduling in contrast to the loss in uplink to reporting overhead.</p><p>System simulations show that the gain from channel dependent scheduling is substantial but highly cell layout dependent. The gain with frequency and time CDS, compered to CDS in time domain only, is also large, around 20\%. With a full uplink it can still be a considerable gain in downlink performance if a large overhead is used for channel quality reports. This gives a loss in uplink performance, and if the uplink gets to limited it will severely affect both uplink and downlink performance negatively.</p><p>How to schedule and transmit CQI-reports is also under consideration. A suggested technique is to transmit the CQI reports together with uplink data. With a web traffic model simulations show that a high uplink load is required to get the reports often enough. The overhead also gets unnecessary large, if the report-size only depends on the allocated capacity.</p>

Telecommunication systems are under constant development. Currently 3GPP is working on an evolution of the 3G-standard, under the name 3G Long Term Evolution (LTE). Some of the goals are higher throughput and higher peak bit rates. A crucial part to achieve the higher performance is channel dependent scheduling (CDS). CDS is to assign users when they have favorable channel conditions. Channel dependent scheduling demands accurate and timely channel quality reports. These channel quality indication (CQI) reports can possibly take up a large part of the allocated uplink. This thesis report focuses on the potential gains from channel dependent scheduling in contrast to the loss in uplink to reporting overhead. System simulations show that the gain from channel dependent scheduling is substantial but highly cell layout dependent. The gain with frequency and time CDS, compered to CDS in time domain only, is also large, around 20\%. With a full uplink it can still be a considerable gain in downlink performance if a large overhead is used for channel quality reports. This gives a loss in uplink performance, and if the uplink gets to limited it will severely affect both uplink and downlink performance negatively. How to schedule and transmit CQI-reports is also under consideration. A suggested technique is to transmit the CQI reports together with uplink data. With a web traffic model simulations show that a high uplink load is required to get the reports often enough. The overhead also gets unnecessary large, if the report-size only depends on the allocated capacity.

<p>One goal in the development of future cellular systems is to increase performance. Channel dependent scheduling can possibly contribute to a performance enhancement. It requires channel qualityinformation and uplink channel knowledge is often incomplete. This master thesis work compares channel dependent scheduling and channel independent scheduling for a Single Carrier Frequency Division Multiple Access-based uplink in time domain and time and frequencydomain assuming continuous channel quality information updates. It also evaluates different methods for providing channel quality information by investigating how the limited channel knowledge they supply affects the performance of channel dependent scheduling.</p><p>Single-cell simulations with perfect channel knowledge indicate small gains for channel dependent scheduling. Large gains are seen when performing frequency and time domain scheduling instead of only time domain scheduling. Limited channel knowledge causes performance loss for channel dependent scheduling. The performance is only slightly decreased if a method with sufficiently frequent providing of channel quality information updates is applied.</p><p>More realistic multi-cell simulations show large gains for channel dependent scheduling. It is possible that these results are influenced by link adaptation and scheduling problems due to non predictable interference when performing dynamic scheduling. In the comparison between channel dependent and channel independent scheduling the channel dependent scheduling can benefit from the fact that the selected channel dependent scheduling algorithms result in a more static scheduling than the selected channel independent scheduling algorithms do.</p>

One goal in the development of future cellular systems is to increase performance. Channel dependent scheduling can possibly contribute to a performance enhancement. It requires channel qualityinformation and uplink channel knowledge is often incomplete. This master thesis work compares channel dependent scheduling and channel independent scheduling for a Single Carrier Frequency Division Multiple Access-based uplink in time domain and time and frequencydomain assuming continuous channel quality information updates. It also evaluates different methods for providing channel quality information by investigating how the limited channel knowledge they supply affects the performance of channel dependent scheduling. Single-cell simulations with perfect channel knowledge indicate small gains for channel dependent scheduling. Large gains are seen when performing frequency and time domain scheduling instead of only time domain scheduling. Limited channel knowledge causes performance loss for channel dependent scheduling. The performance is only slightly decreased if a method with sufficiently frequent providing of channel quality information updates is applied. More realistic multi-cell simulations show large gains for channel dependent scheduling. It is possible that these results are influenced by link adaptation and scheduling problems due to non predictable interference when performing dynamic scheduling. In the comparison between channel dependent and channel independent scheduling the channel dependent scheduling can benefit from the fact that the selected channel dependent scheduling algorithms result in a more static scheduling than the selected channel independent scheduling algorithms do.