HSPA+ Evolution to Release 12: Performance and Optimization

8 Advanced UE and BTS Algorithms

Antti Toskala and Hisashi Onozawa

8.1 Introduction

This chapter presents an overview of recent developments of the advanced UE as well as of advanced BTS algorithms. First the different UE receiver versions are introduced based on the work done in different 3GPP Releases for defining advanced UE performance requirements. This chapter then continues with the introduction of the different scheduling solutions in BTS and then continues to cover BTS interference cancellation. This chapter is concluded with the outlook for looking at other aspects of the UE and BTS algorithms, including the latest development of Network Assisted Interference Cancellation (NAIC) being investigated in 3GPP for Release 12.

8.2 Advanced UE Receivers

The first UE implementations on Release 99 were single receiver solutions based on the traditional Rake receiver, as introduced in [1]. Work then followed to cover the following types of receivers:

• Type 1 receiver in Release 6, which introduced two-antenna receiver diversity in the UE receiver, which became a typical solution especially in data centric products such as USB dongles and ExpressCards. The practical challenges related to design include achieving a low enough correlation between the antennas, especially with the lower frequency bands below 1 GHz. The small size of a device such as a USB dongle adds to the design challenge. Figure 8.1 shows an example performance impact of the antenna correction effect as introduced ...