【資料名稱】：Channel Quality InformationReporting and

【資料作者】：Erik Eriksson

【資料日期】：2008

【資料語言】：英文

【資料格式】：PDF

【資料目錄和簡介】：

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.

[ 本帖最后由 smartcat 于 2010-3-5 11:24 編輯 ]