An uplink distance measuring method, device and base station

Abstract

The invention discloses an uplink ranging method, a device and a base station. Based on an orthogonal frequency division multiple access (OFDMA) system, the invention comprises the following steps: the base station selects a group of candidate ranging code sequences from the reference ranging sequences and calculates the correlation peak when the non-matching happens according to the time domain peak of a related detectable quantity; the double peaks are detected according to the candidate ranging code sequence and whether the distance between the double peaks is larger than a preset threshold is judged; if the distance between double peaks is larger than the preset threshold, then the ranging code is discarded, otherwise, a frequency offset, a received power and a timing offset are acquired, a decision threshold is calculated and the active ranging code is acquired according to the decision threshold. In the invention, a group of candidate ranging code sequences are selected according to the decreasing sequence of the time domain peak of the related detectable quantity and then the double-peak detection is utilized to ensure the legal availability of the candidate ranging code sequences, and finally the screened ranging codes are utilized to estimate the frequency offset, received power and timing offset, thus enhancing the precision of the detection.

Description

Technical field [0001] The invention relates to an orthogonal frequency division multiple access (OFDMA, Orthogonal Frequency Division Multiple Access) technology, in particular to an uplink ranging method, device and a base station based on an OFDMA system. Background technique [0002] OFDMA technology is a multi-user multiplexing and access technology based on Orthogonal Frequency Division Multiplexing (OFDM). For OFDMA system, all sub-carriers are divided into multiple sub-channels. Each sub-channel is composed of several sub-carriers. The system can allocate resources from the two dimensions of sub-channel and time slot. Therefore, the granularity of resource allocation is small and the flexibility is relatively small. Higher. [0003] Due to the randomness of the location of each mobile user in the cell, the time of each uplink user signal received by the base station will be affected by the round trip delay (Round Trip Delay), resulting in the misalignment of the OFDMA sym...

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Problems solved by technology

[0045] According to the calculation principle given, since |I in formula (7) m +N m |Set the time-domain average of the minimum peak corresponding to the ranging code, resulting in a large calculation error

Similarly, the calculation of also has similar problems, resulting in a large error between the set decision threshold η and the actual value

In addition, the received power of the ranging code is calculated in the time domain, since r(0) and |S m |It is difficult to estimate accurately, which reduces the estimation accuracy of received power

[0046] In addition, the existing algorithm only uses a single decision threshold η to exclude false ranging codes, and the probability of false alarms is high, especially when the ranging time slot does not contain ranging codes, it is more likely to cause false alarms.

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