Method and apparatus for pilot frequency multiplexing in OFDM system

Abstract

This invention provides a CQI pilot multiplex method based packeting including: a transmission end converts a generated pilot sequence to a frequence domain then carries out mapping of sub-carriers in terms of the following mode: distributing DM pilot frequences crossly on two short blocks of a sub-frame on a frequency domain and interval of sub-carries of DM pilot freequency on each short block is the same, dividing CQI pilot frequency to several sets to be distributed on the preserved sub-carriers on two short blocks and the numbers and intervals of the sub-carriers of each set of CQI pilot. This invention also provides a CQI pilot multiplexing device based on packeting including a mapping unit of a transmission end used in mapping sub-carriers of pilot frequency after converting the generated pilot sequence to the frequency domain.

Description

technical field [0001] The present invention relates to the field of communication, in particular to a pilot multiplexing method and device in an OFDM system. Background technique [0002] Orthogonal Frequency Division Multiplexing (OFDM: Orthogonal Frequency Division Multiplexing) technology has reached a consensus in the industry as a basic transmission technology used in the B3G mobile communication system. In the OFDM communication system defined by the 3GPP LTE plan, the uplink adopts a Discrete Fourier Transform-Spread-Orthogonal Frequency Division Multiplexing (DFT-S-OFDM: Discrete Fourier Transform-Spread-Orthogonal Frequency Division Multiplexing) scheme. Each subframe includes two short blocks and six (for a Frequency Division Duplex (FDD: Frequency Division Duplex) system) or eight (for a Time Division Duplex (TDD: Time Division Duplex) system) long blocks. [0003] As shown in FIG. 1 , the uplink subframe structure of the FDD system defined by the 3GPP LTE plan....

AI Technical Summary

Problems solved by technology

[0009] However, in the above-mentioned existing method 1, there are fewer orthogonal CQI pilot channels, because SB2 is completely used for the transmission of DM pilots, and SB1 is used for CQI pilots, which means that the resources reserved for CQI pilots are 1 / 2 of all pilot resources, therefore, this method cannot flexibly reserve more resources for CQI pilots

In addition, when the UE speed is high, since the first column of pilots in this method cannot provide more help for the channel estimation of the UE terminal, it will lead to performance degradation

[0010] In the above-mentioned existing method 2, the CAZAC sequence used for the CQI pilot is relatively short, resulting in fewer available CAZAC sequences, which brings difficulties in allocating CAZAC sequences between cells

For example: the CQI pilot frequency domain interval is 6 subcarriers, and the CAZAC sequence used is 1 / 6 of the length of the CAZAC sequence in method 1, then the number of CAZAC sequences of this length is 1 / 6 of the number of CAZAC sequences in method 1 , so it will bring difficulties to the allocation of CAZAC sequences among cells

In addition, the code division CQI pilot has strict requirements on the DM pilot distribution, such as the DM pilot interval is 2, which limits the number of orthogonal CQI pilot channels

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