System and method for decoding high-speed parallel Turbo codes in LTE (Long Term Evolution) system

Abstract

The invention provides a decoding method for Turbo codes. The method comprises the following steps of: firstly judging whether the length K of a code block is larger than 768, if so, storing the input three paths of soft information into an input storage unit segmentally, if not, storing the three paths of soft information into a preset input storage unit, then acquiring the values of the soft information from the preset input storage unit through a preset MAP (Maximum posterior probability) unit to carry out iteration decoding calculation, wherein the values generated during the decoding calculation is stored in a preset local storage unit; continuously judging whether the eight MAP units of a Turbo code decoder are in a ready state, if so, acquiring the values of the soft information from different input storage units by each MAP unit for carrying out iteration decoding calculation, wherein the values generated during the decoding calculation are respectively stored in a plurality of local storage units; finally, determining whether reaching the maximum times of iterations or whether passing the CRC (cyclic redundancy check), if so, carrying out hard decision output on the soft information, and storing the K output results in an output storage.

Description

technical field [0001] The present invention relates to a decoding system and method, in particular to a decoding system and method for high-speed parallel Turbo codes in a Long Term Evolution (Long Term Evolution, LTE) system. Background technique [0002] The LTE system requires the peak rate of the downlink to reach 100Mb / s, and the peak rate of the uplink to reach 50Mb / s, which puts forward higher requirements for the decoding speed of the channel coding. At present, the Turbo decoding algorithm that has been applied to the chip design is mostly for For Rel 6, if LTE continues to use the Turbo code decoding method in Rel 6, it cannot meet the above data rate requirements. [0003] There are many implementation schemes for the Turbo code decoding accelerator of the LTE system, and the known common methods are as follows: [0004] One is to expand the sliding window method commonly used in Turbo code decoding to a parallel method. The decoder of Turbo codes in Rel 6 usual...

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Problems solved by technology

[0005] In the above-mentioned sliding window method, the number of windows is at least 4, and the number of windows is usually 8 or 16 during implementation, so that the length of the window becomes shorter, because each window must reserve a certain length (at least 16 bits) training sequence, when the window length itself is not very long, the calculation time overhead occupied by the training sequence cannot be ignored, and the length of the window and the length of the training sequence become shorter, and the decoding performance will be greatly affected

Although the calculation method of the above-mentioned interleaving address avoids the power calculation, the speed of the decoder will also be reduced every time the interleaving address is calculated.

[0006] Some researchers have proposed the rapid processing methods of Radix-4 and Radix-8, but because these methods increase the critical path, and the resource consumption of the system is also increased by the same order, in fact, the calculation unit and the storage unit are doubled. In exchange for double the speed, there is no essential improvement in the performance of the decoding accelerator

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