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OFDMA downlink communication method and system based on FFT precoding

A downlink and communication method technology, applied in the field of wireless broadband access, can solve the problems that the downlink cannot be directly applied, and the transmitter cannot realize multi-channel user data multiplexing, so as to alleviate the increase of peak-to-average ratio and ease The peak-to-average ratio is high and the effect of reducing the update cost

Inactive Publication Date: 2010-01-27
GCI SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, because this method only uses a small part of the frequency band for the transmitter, and the other frequency bands are not used for data transmission, this makes the transmitter unable to multiplex user data, and downlinks such as broadcast data transmission must function and therefore cannot be directly applied to the downlink

Method used

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  • OFDMA downlink communication method and system based on FFT precoding
  • OFDMA downlink communication method and system based on FFT precoding
  • OFDMA downlink communication method and system based on FFT precoding

Examples

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Embodiment 1

[0035] see figure 1 As shown, it is a schematic diagram of Embodiment 1 of the FFT precoding-based OFDMA downlink communication method of the present invention. In this embodiment, the process of performing FFT precoding on user data is added at the base station transmitter to effectively alleviate the bottleneck of high peak-to-average ratio when the base station transmitter transmits signals.

[0036] like figure 1 As shown, according to the OFDMA downlink communication method based on FFT precoding in this embodiment, when the base station transmitter needs to send information data to the user receiver: the base station transmitter first encodes and modulates the original data of each user respectively, and Perform FFT precoding processing on the coded and modulated data respectively, then perform subcarrier mapping on all user data after the FFT precoding processing, and perform the first IFFT operation on the data after subcarrier mapping, and add the cyclic prefix opera...

Embodiment 2

[0044] see figure 2 As shown, it is a schematic diagram of Embodiment 2 of the OFDMA downlink communication method based on FFT precoding of the present invention. In this embodiment, the main difference from the above Embodiment 1 is that this embodiment can freely set Set the number of users.

[0045] like figure 2 As shown, in the OFDMA downlink communication method based on FFT precoding in this embodiment, the selection of the optimal number of users K of the system is firstly performed according to different system requirements, and after the number of users K is selected, according to the selected The K codes and modulates the information data of each user.

[0046] According to the OFDMA downlink communication system based on FFT precoding corresponding to this mode, it also includes a user number selection module connected to each coding and modulation module, so as to select the optimal number of users K of the system according to different system requirements, ...

Embodiment 3

[0055] see image 3 As shown, it is a schematic diagram of Embodiment 3 of the OFDMA downlink communication method based on FFT precoding in the present invention. In this embodiment, the difference from the above Embodiment 1 mainly lies in that the transmitter in this embodiment The processing process of frequency domain equalization is performed, so that the design of the user receiver can be further simplified.

[0056] like image 3 As shown, in the solution of this embodiment, after the base station transmitter performs subcarrier mapping processing on the FFT precoded signal, it also performs frequency domain pre-equalization processing on the signal after subcarrier mapping, and after the subcarrier mapping The frequency-domain pre-equalization operation is performed on the signal, and then the first IFFT operation, adding a cyclic prefix, and other operations are performed on the frequency-domain pre-equalized signal.

[0057] Correspondingly, the OFDMA downlink com...

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Abstract

The invention discloses an OFDMA downlink communication method and a downlink communication system based on FFT precoding. FFT precoding operation is performed on modulated and coded data to reduce a peak-to-average ratio when a transmitter of a base station needs to transmit data, which effectively relieves bottleneck of relatively higher peak-to-average ratio when the base station transmits a signal; in addition, the data are dispersed to various frequency points by the FFT precoding operation instead of being directly generated in a frequency domain, which can effectively utilize a frequency diversity by a multi-path channel and improve error code performance of the system. Meanwhile, the system keeps a frequency multiple-access advantage of an existing OFDMA system, unitedly maps frequency components of different user data onto different frequency points and achieves a multiple access effect, therefore, manners such as multi-path user data multiplexing, general broadcast data transmission, sub-carrier mapping and the like can be compatible with the existing OFDMA system, which can greatly reduce upgrade cost of equipment.

Description

technical field [0001] The present invention relates to the technical field of wireless broadband access, in particular to an OFDMA downlink communication method based on FFT precoding and an OFDMA downlink communication system based on FFT precoding. Background technique [0002] During the standardization evolution process of 3GPP LTE, various multiple access schemes have emerged, such as multi-carrier code division multiple access (MC-CDMA), multi-carrier time division multiplexing synchronous code division multiple access (MC-TD- SCDMA), Orthogonal Frequency Division Multiple Access (OFDMA), etc. Among them, OFDMA has become the mainstream multiple access scheme for the downlink, and is a popular candidate for the uplink. ) can convert severe frequency selective channels into several flat sub-channels, which can effectively combat frequency selective fading in wireless communication environments, and because the sub-channels are orthogonal to each other, high spectrum ut...

Claims

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Application Information

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IPC IPC(8): H04L5/02H04L27/26
Inventor 伍沛然张永强
Owner GCI SCI & TECH