GFDM/CDMA hybrid multiple access wireless access method

Abstract

The invention discloses a GFDM / CDMA hybrid multiple access wireless access method so that the interference between sub carriers of the GFDM can be eliminated. The method is characterized in that a spread slotted ALOHA is introduced in a generalized frequency division multiplexing (GFDM) / code division multiple access (CDMA) hybrid multiple-access wireless access system of a multi-carrier transmitter, so that a problem that the interference is caused between users using adjacent sub carriers is solved. After the user completes time-frequency synchronization of a base station, all users send uplink data with base station arrival times being all time slot starting times randomly; the K sub carriers are employed and each sub carrier is able to carry a GFDM system with the symbol number being Mto number the sub carriers; and when the users send data, PN sequences are added between the adjacent sub carriers to carry out spread spectrum, the same PN1 is used for sub carriers with odd numbers,and the same PN2 s used for sub carriers with even numbers, so that the interference between the non-orthogonal sub carriers is eliminated.

Description

technical field [0001] The invention relates to a wireless communication multiple access technology field based on generalized frequency division multiplexing (GFDM) (Generalized Frequency Division Multiplexing), especially a hybrid multiple access technology combining generalized frequency division multiple access and spread spectrum time slot Aloha. Background technique [0002] In recent years, ultra-wideband wireless communication systems usually use extremely short-duration pulse waveforms to modulate the transmitted data, and the modulation bandwidth is extended to several GHz levels, so that the system has low power consumption and extremely high data transmission rates. High, strong anti-multipath and narrow-band interference capabilities, large user capacity and a series of unique advantages. In a multi-user system, the receiver is interfered not only by background noise but also by other transmitting users. Since the phase and time delay of the interference pulse ...

AI Technical Summary

Problems solved by technology

However, OFDM multi-carrier technology is not applicable in some application scenarios due to its large out-of-band radiation, high peak-to-average power ratio, and sensitivity to frequency offset.

When different users randomly access the same time slot, as long as they do not use the same subcarrier, the system can still distinguish between different users, but the problem here is that if the user selects an adjacent subcarrier, the adjacent subcarrier Carrier users will interfere with each other, which is difficult to achieve

Although GFDM can expand the data into a time-frequency two-dimensional block structure, each block contains multiple sub-carriers and sub-symbols, and the number of sub-carriers and sub-symbols can be flexibly configured according to different transmission scenarios, but this multi-carrier technology and time-frequency , code-domain hybrid multiple access technology is still difficult to combine

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