Synchronous estimating method and device of OFDM system
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A technology of estimated value and frequency synchronization, applied in multi-frequency code systems and other directions, it can solve the problems of large delay in calculation results and high computational complexity
Active Publication Date: 2012-05-23
RDA CHONGQING MICROELECTRONICS TECH CO LTD
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[0004] Chinese patent 200810232936.1 provides a wireless communication timing synchronization method and cell search method and system, which uses the decoded correct information to reconstruct the transmitted modulated signal, and completes the frequency synchronization estimation process on the basis of the reconstructed modulated signal. However, it needs to reconstruct the received signal in real time to estimate the frequency synchronization information. The real-time nature leads to the disadvantages of high computational complexity and large delay in calculation results, which increases the processing time of the user terminal (UE, User Equipment) in the communication system. the complexity
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specific Embodiment 1
[0035] Taking the LTE system as an example, the physical channel is reconstructed as a physical broadcast channel (PBCH, Physical Broadcast Channel), figure 1 is the mapping pattern of the short CP physical broadcast signal and the cell common reference signal in the subframe in the LTE system, figure 2 It is a mapping diagram of the long CP physical broadcast signal and the cell common reference signal in the subframe in the LTE system, and the implementation of the technical solution will be further described in detail below.
[0036] image 3 A schematic flow chart of a preferred embodiment of the time synchronization estimation method of the present invention is given, as shown in the figure, the method includes:
[0037] Step 1, the terminal reconstructs and generates PBCH frequency domain data according to the received and decoded correct bit sequence
[0038] in Represents frequency domain data including PBCH and Cell-specific Reference Signals (CRS, Cell-specifi...
specific Embodiment 2
[0090] Taking the LTE system as an example, the physical channel is reconstructed as a physical downlink shared channel (PDSCH, Physical Downlink Share Channel) carrying a system information block (SIB, SystemInformationBlockType1). The following will take the PDSCH carrying SIB1 as an example to further implement the technical solution a detailed description of .
[0091] image 3 A schematic flow chart of a preferred embodiment of the time synchronization estimation method of the present invention is given, as shown in the figure, the method includes:
[0092] Step 1, the terminal reconstructs and generates PDSCH frequency domain data according to the received bit sequence containing SIB1 information and correctly decoded
[0093] in Represents frequency domain data including PDSCH and CRS, i=0, 1,..., L, j=0, 1,..., K, n rf =0, 1, 2, ..., 7, where L represents the number of OFDM symbols occupied by the PDSCH, and K represents the number of subcarriers occupied by the ...
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Abstract
The invention relates to the field of a radio communication system, particularly to a synchronous estimating method of an OFDM system. The method comprises the steps of: reconfiguring transmitted frequency domain data according to bit sequences with correct coding and received specific channel to response obtained frequency domain channel related to the frequency domain data; counting synchronousestimating value of time and/or frequency based on the frequency domain channel response, wherein the specific channel is the channel in which the transmitting bit sequence is unchanged in the updating cycle and the terminal can determine the time following updating cycle arrived. The invention also provides a synchronous estimating device of an OFDM system. In the invention, the transmitted frequency domain data produced by reconfiguration with information unchanged is stored in the terminal; the synchronous estimating value is estimated on real time only; the complexity and counting delay in real-time operating can be reduced; the synchronous estimating value in the OFDM system is more precise; the accuracy on synchronization is raised; the accessing reliability of the terminal is improved; and the performance of the terminal to receive the data is raised.
Description
technical field [0001] The present invention relates to the field of wireless communication systems, in particular to a downlink synchronization estimation method and device applied to an Orthogonal Frequency-Division Multiplexing (OFDM, Orthogonal frequency-division multiplexing) system for initial cell search or normal residence, including time Synchronization and frequency synchronization. Background technique [0002] With the development of society and the advancement of technology, people hope that the system can provide large-capacity, high-speed, and low-latency data transmission services. Currently, the 3rd Generation Partnership Project (3GPP, 3 rd Generation Partnership Project) long-term evolution (LTE, Long-Term Evolution) system and enhanced long-term evolution (LTE-Advanced) system, global microwave interconnection access (Wimax, Worldwide Interoperability for Microwave Access system and China Mobile Multimedia Broadcasting (CMMB, China MobileMultiMedia Bro...
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