Multi-user radio relay method and system
A wireless relay, multi-user technology, applied in wireless communication, advanced technology, electrical components, etc., can solve the problems that relay users cannot receive base station data correctly, do not know the channel conditions between each other, and are difficult to use diversity technology, etc. Achieve the effect of avoiding the increase of the bit error rate, utilizing the diversity gain, and reducing the overhead
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Embodiment 1
[0051] When the OFDM modulation method is adopted, the downlink data transmission process from the base station to the user includes the following steps:
[0052] Step 1. In the sending phase, the base station sends the data of the target user to all users with a certain transmission power and transmission rate. Wherein, the modulation method used is OFDM, that is, the data of each target user occupies a part of subcarriers in all subcarriers, and the subcarriers occupied by each user are different.
[0053] Step 2. In the sending phase, all users can receive the data sent by the base station. After receiving the data, the relay user only keeps the data of several target users in its own storage unit. The reserved criterion is that the subcarriers where the data of these users are located have a frequency-selective fading channel whose fading is less than the threshold C 1 .
[0054] Step 3. In the CQI detection stage, the OFDM-modulated signal sent by the data target user ...
Embodiment 2
[0061] When using CDMA to distinguish multiple users, the downlink data transmission process from the base station to the user includes the following steps:
[0062] Step 1', in the sending phase, the base station sends the data of the target user to all users with a certain transmission power and transmission rate. The data between different target users is distinguished by CDMA spreading codes, and each user can use spreading codes with different numbers and lengths according to the different data traffic.
[0063] Step 2', in the sending phase, all users can receive the data sent by the base station. After receiving the data, the relay user only keeps the data of several target users in its own storage unit. The standard of retention is: only retain the data of G users with the best quality at most, and at the same time, the fading experienced by these user data is less than the preset threshold C 1 .
[0064] Step 3', in the CQI detection stage, the target user does not...
Embodiment 3
[0069] Such as Figure 9 As shown, it is a multi-user wireless relay system, including a base station and a user terminal, and the base station is connected to the user terminal; the base station has a downlink data generation unit for generating a detection frame containing channel quality information downlink data; such as Figure 10 As shown, the user terminal includes: a target user data storage unit, which is used to selectively store data of some target users; a target user selection unit, which is used to select users whose channel quality information is greater than a threshold as target users; a transmit diversity unit , use the channel quality information to perform space-time coding on the forwarded data, and use the multiple-input multiple-output multi-antenna technology to send, each relay user randomly selects a branch of space-time coding; the combining unit is used to receive signals from the base station and The data of different relay users is merged.
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