Low complexity PAPR reduction methods for carrier-aggregated MIMO OFDMA and SC-FDMA systems

Pochun Yen,Hlaing Minn

doi:10.1186/1687-1499-2012-179

Abstract

New generation wireless systems target to support much higher data rate which requires larger bandwidth than the existing systems. Lack of contiguous spectrum resources and the compatibility requirement with the legacy systems make the concept of carrier aggregation (CA) a practical means for supporting high data rate in next generation systems. One of the practical issues related to the CA is the dramatically increased peak-to-average power ratio of the time domain signal. This article proposes several low-complexity and no-overhead PAPR reduction methods for bandwidth aggregated systems with orthogonal frequency division multiplexing/multiple-access or single-carrier frequency division multiple access in multi-in multi-out system configurations. For the proposed phase-rotation based PAPR reduction methods, a reliable phase rotation detector at the receiver is developed to maintain the receiver performance. Performance evaluation under 3GPP LTE-Advanced environment shows the advantage of the proposed methods while not requiring any signaling overhead.

Highlights

The demand of higher data rate to support various wireless services and applications increases dramatically over the last decade. 3GPP has adopted carrier aggregation (CA) [1] where multiple LTE Release 8 [2,3] component carriers (CCs) are combined to provide the targeted or required data rate
We propose to use the pilots inserted for channel estimation and tracking according to the standard specification, eliminating requirement of additional pilots at each multiple access (MA) symbol, i.e., either OFDMA or single carrier frequency division multiple access (SC-FDMA) symbol
The proposed multi-symbol SLM (MSSLM) reduces the complexity and removes the signaling overhead required by the traditional selective mapping technique (SLM) scheme with the introduction of the multi-symbol optimization interval together with the aid of a reference/pilot signal within that interval

Summary

Introduction

The demand of higher data rate to support various wireless services and applications increases dramatically over the last decade. 3GPP has adopted carrier aggregation (CA) [1] where multiple LTE Release 8 [2,3] component carriers (CCs) are combined to provide the targeted or required data rate. Regarding PSLM, MSSLM and SSLM, while adopting SLM concept, our contributions include (i) the concept of multi-symbol PAPR optimization intervals for signaling overhead reduction, (ii) the concept of partial group selection for complexity reduction, (iii) adaptation to CA systems, (iv) the extension to the MIMO scenarios, and (v) a reliable phase rotation detector at the receiver to remove the effects of PAPR reducing phase rotations on the receiver performance. These methods provide low-complexity and require no signaling overhead by the exploitation of existing reference symbols for signaling overhead reduction.

Resouce Block Interval

UL model

Proposed PAPR reduction methods

System setup

Conclusions