Frequency synchronization for generalized OFDMA uplink

Zhongren Cao, Ufuk Tureli, Yu Dong Yao, Patrick Honan

Research output: Contribution to conferencePaperpeer-review

92 Scopus citations

Abstract

In orthogonal frequency division multiple access (OFDMA), the total spectral resource is partitioned into multiple orthogonal subcarriers. These subcarriers are assigned to different users for simultaneous transmission. OFDMA is very sensitive to frequency synchronization errors. In an unsynchronized OFDMA uplink, each user has a different carrier frequency offset (CFO) relative to the common uplink receiver. The orthogonality among subcarriers is thus destroyed resulting in multiple access interference as well as self interference. This problem is tackled in this paper by constructing the orthogonal spectral signals that would have been received if all users were frequency synchronized. A generalized OFDMA is described first considering arbitrary subcarrier assignments. A new signal model is formulated to characterize the interference on the generalized OFDMA uplink due to multiuser frequency synchronization errors. Least squares (LS) and minimum mean square error (MMSE) criteria are used to construct the orthogonal spectral signals from one received OFDMA block. An efficient implementation method is developed based on a banded matrix approximation, which is computationally inexpensive and provides good performance.

Original languageEnglish
Pages1071-1075
Number of pages5
StatePublished - 2004
EventGLOBECOM'04 - IEEE Global Telecommunications Conference - Dallas, TX, United States
Duration: 29 Nov 20043 Dec 2004

Conference

ConferenceGLOBECOM'04 - IEEE Global Telecommunications Conference
Country/TerritoryUnited States
CityDallas, TX
Period29/11/043/12/04

Fingerprint

Dive into the research topics of 'Frequency synchronization for generalized OFDMA uplink'. Together they form a unique fingerprint.

Cite this