Variable band width frequency-shift and frequency-selective digital repeater

Abstract

The invention relates to a variable band width frequency-shift and frequency-selective digital repeater which comprises a base station, an access machine and a remote machine, wherein the access machine comprises a downlink duplexer, a step attenuator, a downlink frequency shifter, a power amplifier and an uplink duplexer that are sequentially connected with each other in a downlink way; the access machine further comprises a low noise amplifier, an uplink frequency shifter and a downlink duplexer that are sequentially connected with each other in an uplink way; the uplink frequency shifter and the downlink frequency shifter are internally cured with frequency conversion program; the remote machine includes a downlink duplexer, a downlink low noise power amplifier, a downlink digital frequency-shift and frequency-selective module, a downlink companding frequency-shift unit and a downlink power amplifier which are sequentially connected with each other in a downlink way; the remote machine further includes an uplink duplexer, an uplink low noise power amplifier, an uplink digital frequency-shift and frequency-selective module, an uplink companding frequency-shift unit and an uplinkpower amplifier that are sequentially connected with each other in an uplink way; and the uplink and the downlink digital frequency-shift and frequency-selective modules are internally cured with frequency-shift and frequency-selective program. The digital repeater can achieve the aim of controlling band width by the frequency conversion program and the frequency-shift and frequency-selective program, thus having strong noise suppression capability and low frequency interference risk.

Description

technical field [0001] The invention relates to a digital repeater, in particular to a frequency-shifting frequency-selective digital repeater with variable bandwidth applied to a mobile communication system, and belongs to the technical field of mobile communication. Background technique [0002] The repeater is an extremely effective device used to make up for the lack of base station coverage in the mobile network, expand the coverage of the base station, fill in the coverage blind spots, and solve the signal coverage of the mobile signal blind spots within the coverage of the base station or at the edge of the base station coverage. [0003] In the mobile communication network, the cellular mobile communication system often has some blind areas that cannot be covered by the base station signal due to terrain and transmission conditions. In general, the same-frequency repeater (usually referred to as "repeater" for short) is often used. ”), directional radiation to the ar...

AI Technical Summary

Problems solved by technology

Due to technical reasons, the conventional same-frequency repeater has the following problems: 1. The same-frequency repeater can often receive signals from multiple base stations and form interference, and when the distance between two base stations is relatively close , especially when the existing CDMA base stations are basically co-sited with GSM, the frequency interval between the two is only 20MHz, and the C network co-frequency repeater interferes with the G network and C network base stations, and the phenomenon of call drop and noise is relatively common ; 2. Rural wireless mobile communication uses wireless channels in the air to communicate. Since wireless transmission is greatly affected by terrain and features, and the number and location of base stations are limited to a certain extent, there are many in the mobile communication network. Wireless coverage blind areas or wireless signal interference areas cause mobile users to fail to access, call drops or lower call quality; 3. For co-frequency repeaters with high gain, the isolation between the donor antenna and the retransmission antenna is very high. It is often difficult to implement on-site installation, especially in flat terrain; 4. The retransmission antenna can only use directional radiation, and the site is required to be located at the edge of the coverage area, which not only brings difficulties to site selection, but also affects coverage and services Quality; 5. In many cases, because a site with sufficient signal strength cannot be found at the edge of the blind area required to cover, the same-frequency repeater cannot be installed; 6. The key module of the same-frequency repeater is analog frequency selection 7. Traditional frequency shifting technology is likely to cause interference of transmission link signals and a large number of frequency resources occupied

Although this invention estimates the nonlinear characteristics in the feedback channel of the transceiver, thereby effectively reducing the influence of interference signals, it can only achieve a better self-excited cancellation effect

However, problems such as the inability of mobile users to access, call drop, or reduced call quality, difficulty in site selection, signal coverage, and frequency shifting technology to easily cause interference in transmission link signals and a large number of frequency resources have not yet been solved. be fundamentally resolved

Images