LTE Advanced: 3GPP Solution for IMT-Advanced

14.7 Advanced Receivers

The practical data rates are limited by the interference. The data rates can be improved by advanced receivers that are able to manage interference more efficiently. The advanced receivers can be applied both in UE for the downlink and in NodeB for the uplink.

14.7.1 Advanced UE Receivers

Advanced UE receivers are able to tolerate both intra-cell interference and inter-cell interference. The intra-cell interference cancellation is called equalizer and is already included in most HSDPA receivers. 3GPP has defined performance requirements for different type of advanced receivers:

• Type 1 with receiver diversity;
• Type 2 with equalizer;
• Type 3 with receive diversity and equalizer;
• Type 3i with receiver diversity, equalizer and inter-cell interference cancellation.

The receiver algorithms are not defined by 3GPP but are UE vendors specific and can also be better than 3GPP requirements. Simulation results for Type 3 and 3i are shown in Figure 14.11 [2]. The throughput gains with 3i compared to 3 are 20–25% for the cell edge conditions with G-factor of −3 dB and 0 dB. The live network measurements have illustrated even higher gains in practice. The advanced UE receives are nice from the operator point of view because there are no changes required to the network.

Figure 14.11 Throughput gain of the 3i type receiver [2].

14.7.2 Advanced NodeB Receivers

Advanced ...