TY - GEN
T1 - Robust uplink synchronization in MIMO-OFDM systems
T2 - 22nd Wireless and Optical Communications Conference, WOCC 2013
AU - Zhang, Xu
AU - Zhang, Zhongshan
AU - Long, Keping
PY - 2013
Y1 - 2013
N2 - There are some new challenges in Multiple-input Multiple-output (MIMO) systems, e.g., uplink synchronization in full-multiplexing transmission mode systems where several packets are transmitted from different users simultaneously. In MIMO uplink transmission systems, different mobile nodes introduce independent carrier frequency offsets, which makes uplink carrier frequency offset estimation in MIMO systems more difficult than that in single antenna systems. The received training sequence at the base station (receiver) is a superposition of training sequences transmitted from more than one mobile node, which may degrade the synchronization performance. In addition, self-interference may also appear if different training sequences (TS) are transmitted at its different transmit antennas equipped in one mobile node. In this paper, both kinds of interferences in MIMO uplink synchronization are analyzed first, and then a superposition distortion mitigation method is given. For an unbiased carrier frequency offset estimator, its Cramer-Rao Lower Bound (CRLB) is also derived. A Joint Best Linear carrier frequency offset Estimator (JBLUE) is also proposed to explore receive antenna diversity in MIMO systems. A new group of training sequences called Round-Robin training sequence group are also proposed in this paper, which outperform conventional training sequences especially for uplink synchronization.
AB - There are some new challenges in Multiple-input Multiple-output (MIMO) systems, e.g., uplink synchronization in full-multiplexing transmission mode systems where several packets are transmitted from different users simultaneously. In MIMO uplink transmission systems, different mobile nodes introduce independent carrier frequency offsets, which makes uplink carrier frequency offset estimation in MIMO systems more difficult than that in single antenna systems. The received training sequence at the base station (receiver) is a superposition of training sequences transmitted from more than one mobile node, which may degrade the synchronization performance. In addition, self-interference may also appear if different training sequences (TS) are transmitted at its different transmit antennas equipped in one mobile node. In this paper, both kinds of interferences in MIMO uplink synchronization are analyzed first, and then a superposition distortion mitigation method is given. For an unbiased carrier frequency offset estimator, its Cramer-Rao Lower Bound (CRLB) is also derived. A Joint Best Linear carrier frequency offset Estimator (JBLUE) is also proposed to explore receive antenna diversity in MIMO systems. A new group of training sequences called Round-Robin training sequence group are also proposed in this paper, which outperform conventional training sequences especially for uplink synchronization.
UR - https://www.scopus.com/pages/publications/84893254573
U2 - 10.1109/WOCC.2013.6676346
DO - 10.1109/WOCC.2013.6676346
M3 - Conference contribution
AN - SCOPUS:84893254573
SN - 9781467356992
T3 - Proceedings - 2013 Wireless and Optical Communications Conference, WOCC 2013
SP - 85
EP - 90
BT - Proceedings - 2013 Wireless and Optical Communications Conference, WOCC 2013
Y2 - 16 May 2013 through 18 May 2013
ER -