【資料名稱】：A Robust Frequency Tracking Loop at the

【資料作者】：Roberto Rimini, Jun Ma

【資料日期】：2008

【資料語(yǔ)言】：英文

【資料格式】：PDF

【資料目錄和簡(jiǎn)介】：

4G systems like LTE (Long term Evolution) provide
an uplink data rate up to 80 Mbps, utilize higher order
modulation (64-QAM) and introduce space division multiple
access (SDMA) to improve spectral efficiency. These features
pose stringent frequency and time synchronization requirements
for the modem to guarantee satisfactory performance. This paper
presents a simple yet robust scheme to estimate the frequency
offset on a per user-basis at the eNodeB. The algorithm proposed
utilizes a non-coherent method to provide frequency error
estimation, hence decoupled from the channel estimator. This
estimation can be used by the eNodeB in a “open loop” fashion to
correct the user’s local oscillator frequency via downlink (DL)
timing adjustment messages or in a “closed loop” scheme such as
frequency tracking loop (FTL) to iteratively reduce the
measurement error fluctuations. The performance of the
proposed estimator have been investigated in open loop
configuration through simulations and found within 5% of
Cramer-Rao bound (CRB) in AWGN channel. For closed loop
operation mode, the presented FTL exploits multipath diversity
in time and space to mitigate the effects of fading, thus showing
less than 0.3dB of performance gap with respect to perfect
frequency correction in TU-30kmh channel.
Analysis is presented for both open loop and closed loop to
provide further insights in the algorithm and to allow parameter
optimization study, thus facilitating the design process.

[ 本帖最后由 smartcat 于 2010-4-26 09:13 編輯 ]