DFT algorithm for ZC sequence in PRACH channel of LTE system

Abstract

The invention relates to the technical field of mobile communication, and discloses a DFT algorithm for a ZC sequence in a PRACH channel of a LTE system. The DFT algorithm comprises the following process of: inputting a parameter k into an ROM1, and reading an output parameter k' of the ROM1; inputting a parameter u into an ROM2, and reading an output parameter u' of the ROM2; subtracting Nzc-1 from a value A obtained by adding k' with u' to obtain a parameter B; inputting A and B into a first selector, outputting a result according to a control signal, and inputting the result into an ROM3; reading output data of the ROM3, adding the output data with k to obtain a value C, and subtracting Nzc from the value C to obtain a parameter D; inputting C and D into a second selector, and according to a control signal, obtaining an output result of the second selector; adding a value E obtained after dividing the output result of the second selector by 2 and carrying out rounding with (with reference to the specification) to obtain a parameter F, inputting E and F into a third selector, taking a result G obtained by carrying out mod2 processing on the output result of the second selector as a control signal, and outputting a p value of a rotation factor index; and according to the p value, obtaining a DFT algorithm result of the ZC sequence. According to the scheme, the solving process of the p value is low in storage capacity, and the algorithm is simple.

Description

technical field [0001] The invention relates to the technical field of mobile communication, in particular to a DFT algorithm of a ZC sequence in a PRACH channel of an LTE system. Background technique [0002] In the 3GPP TS36.211 protocol, LTE defines the uplink PRACH channel random access baseband signal as: [0003] [0004] where t represents time, k 0 Indicates the starting position of the RB occupied by the PRACH, k indicates the RB index within the occupied bandwidth, K indicates the subcarrier spacing difference between the random access preamble and the uplink data, β PRACH Indicates the PRACH signal transmission power coefficient, n indicates the ZC sequence index, T CP Indicates the length of the cyclic prefix, f RA Indicates the random access subcarrier spacing, Indicates the frequency domain position of the random access preamble in the resource block, N ZC Indicates the length of the ZC sequence, and its value is related to the preamble format, as show...

AI Technical Summary

Problems solved by technology

[0018] The chirp Z-transform algorithm is used to calculate the DFT transform of the ZC sequence, because the unique properties of the ZC sequence are not used, not only a large number of multipliers are required, but also three FFT / IFFT calculations are required, which is a large amount of calculation

The calculation of DFT by the second method is obviously simpler than the first method, and its complexity is mainly concentrated on the calculation of the p value. The calculation of the p value by using the ROM storage method needs to consume more storage resources; direct calculation also requires a lot of multiplication , modulo operations, and even division operations; the patented method introduced in the references reduces storage capacity through p-value regularity and symmetric relationships, but its calculations are still relatively complicated

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