Relay device, communication system, and relay method

Abstract

The coverage area of a transmission device is expanded by relaying, and frequency utilization efficiency (cell throughput) is improved. Disclosed is a relay device that transmits signals received from a transmission device by a reception device. The relay device is equipped with a received signal processing unit (33) that demodulates the signals received from the transmission device, a selection unit (34) that selects a transmission method that can be demodulated by the reception device from multiple transmission methods, and signal generation units (35a, 35b) that generate signals used by the transmission method selected by the selection unit (34) based on the signals demodulated by received signal processing unit (33).

Description

technical field [0001] The present invention relates to a relay device, a communication system, and a relay method for relaying wireless communication between a transmitting device and a receiving device. Background technique [0002] Conventionally, in next-generation mobile communications, high-speed data transmission is required, and a wider frequency band is required to perform high-speed data transmission. However, when performing wider-band transmission, since the time interval for sampling the received signal becomes shorter, it is necessary to separate the multi-paths that reach the receiver through different paths (paths) that cannot be detected in the conventional technology. Ignore its effects. In a multipath environment, when a received signal is observed in the frequency domain, the influence of frequency selective fading such as distortion of the signal spectrum becomes large. [0003] As a result, if the single-carrier transmission used in conventional secon...

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Problems solved by technology

[0013] However, it takes time and cost to replace facilities such as base stations with facilities that also support 3.9G and 4G, so not only mobile terminals but also base stations must consider the mixed existence of base stations of different generations

In addition, when installing a new base station for 3.9G in the future, building a base station that also supports 2G in consideration of this situation will require cost.

[0014] Moreover, since the new mobile communication methods of the 3.9G and 4G generations are superior to 3G in terms of frequency utilization efficiency, it is better to use the new generation of communication methods for communication as much as possible. However, in the communication between the base station and the mobile station, in the base station or If any of the mobile stations does not support the next-generation communication method, communication cannot be performed

And, for example, when the mobile station only supports 3G and the relay station and base station support not only 3G but also 3.5G and 3.9G, it is better to use 3.9G, which has the highest frequency utilization efficiency among the corresponding transmission methods, for communication between the relay station and the base station. Since the 3G transmission method is used for transmission under the current consideration method, the frequency utilization efficiency decreases

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