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TABLE 3. DYNAMIC PACKET DATA SIMULATION PARAMETERSTime stepMobilityMultislot allocationPower controlAdmission controlPacket schedulingUser droppingUser arrivalsPacket traffic model:• Number of packets per user• Time between packets• Packet size20 msNoNoNoNoFIFOYes, according to a leaky bucket algorithm (lessthan1%)Poisson processWeb browsing:• Geometrical distributionmean of 10 packets• Pareto distributionmean of 10 secondspareto shape parameter 1.4• Log-normal distributionmean of 4.1 kbytesbution function (CDF) of user throughputduring a Web-browsing session for Classicand COMPACT modes. Since the simulationsdo not model multislot allocation, userthroughput on the x-axis is for one timeslot.To obtain a rough estimate of the correspondingdistribution for 7 TS, we canmultiply the values on the x-axis by seven.A multislot allocation scheme, however,will provide an improvement of the actualdistribution that is not captured by suchsimplistic scaling. When the systems areloaded to capacity as defined by the QoSlimit on packet throughput, user throughputis still high. In the COMPACT system,90% of the users obtain throughput that exceeds12 kbit/s per timeslot with 30 activeWeb-browsing sessions on the first carrier.Similarly, in the Classic system, 90% of theusers obtain throughput exceeding17 kbit/s per time-slot with 60 active Webbrowsingsessions.Finally, a look at spectrum efficiency forthe two modes (Figure 13) shows that eventhough COMPACT handles about half asmany users per sector as Classic, it has twicethe spectrum efficiency, thanks to a slimmedbandwidth of 0.6 MHz.Figure 9Carrier throughput versus channel utilizationfor three different frequency-reusepatterns.76 Ericsson Review No. 2, 2000