Simulation results comparing the Type 3 to the Type 3i are presented in Fig. 7.142, assuming perfect
knowledge of the interfering channel matrix. Here we see, for large geometries, 16-QAM offers
significant throughput advantages over QPSK. Also, as the geometry decreases, a crossover region
exists such that QPSK is performing better than 16-QAM. Lastly, we can see that interference-aware
receivers perform better at the lower geometries, where the UE is closer to the cell edge.
Similar observations can be made for the VA30 simulation results shown in Fig. 7.143. What these
two performance figures have done was to show that further performance improvement can be
obtained when the UE receiver is aware of interference. The gains appear to be more pronounced at
the lower geometry values, which correspond to distances further away from the NodeB. In fact, this
technique, in general, provides gain across the cell area, but more so at the cell edge. Regardless of
3G WIDEBAND CDMA 451
FIGURE 7.143 QPSK and 16-QAM performance comparison in a VA30 channel.
FIGURE 7.142 QPSK and 16-QAM performance comparison in a PB3 channel.
FRC = H-Set 3, QAM & QPSK Modulation, DSCH_Ec/Ior = ??“6 dB
Comparison of Type 3i & 3 Receivers in a Pedestrian B Channel
500
900
1300
1700
2100
2500
??“1 1 3 5 7 9 11 13 15
Geometry (dB)
Throughput (kbps)
QPSK, Type 3
QAM, Type 3
QPSK, Type 3i
QAM, Type 3i
FRC = H-Set 3, QAM & QPSK Modulation, DSCH_Ec/Ior = ??“3 dB
Comparison of Type 3i & 3 Receivers in a VA30 Channel
600
1000
1400
1800
2200
2600
??“1 1 5 11 13 15
Geometry (dB)
Throughput (kbps)
QPSK, Type 3
QAM, Type 3
QPSK, Type 3i
QAM, Type 3i
3 7 9
the advanced receiver technique chosen, the system or network benefits will only become visible when
a significant number of the UE within the cell are using them.
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