6.1 Introduction

Uplink transmission in the long term evolution (LTE) of the UMTS (universal mobile telecommunications system) terrestrial radio access system (UTRA LTE) has numerous physical layer advances in comparison to UTRA WCDMA (wideband code division multiple access), mainly to achieve two to three times better spectral efficiency. These advances include flexible channel bandwidth up to 20 MHz, flexible user resource allocation in both time and frequency domains, and a shorter time transmission interval (TTI) of 1 ms. Specifically challenging for the uplink is that these enhancements are to be achieved, preferably, with reduced power consumption to extend the battery life and cell coverage.

The radio access technique is one of the key issues in the LTE uplink air interface. In LTE, orthogonal frequency division multiple access (OFDMA) has been selected as the multiple access scheme for downlink, and single-carrier frequency division multiple access (SC-FDMA) has been selected for uplink. OFDM is an attractive modulation technique in a cellular environment to combat a frequency selective fading channel with a relatively low-complexity receiver [1]. However, OFDM requires an expensive and inherently inefficient power amplifier in the transmitter due to the high peak-to-average power ratio (PAPR) of the multicarrier signal.

An alternative transmission scheme with the same attractive multipath interference mitigation property as OFDM is SC-CP (single-carrier transmission with cyclic prefix) [2 4]. Therefore, SC-CP can achieve a link-level performance comparable to OFDM for the same complexity, but at reduced PAPR [2]. In addition, the performance...