User matching and power distribution methods for MIMO-NOMA downlink communication system

A power distribution method for a MIMO-NOMA downlink communication system, comprising:

• sorting respective channel gains of users, if a total number of the users is not an even number, directly excluding a user with the lowest channel gain to exclusively share a channel, and equally dividing all the users into a strong user group and a weak user group according to a channel gain sorting result, wherein a group with a larger channel gain is the strong user group, and a group with a smaller channel gain is the weak user group;
• sequentially selecting a user in the strong user group, and calculating a correlation coefficient between the user and each user in the weak user group, if the correlation coefficient is greater than or equal to a preset threshold, selecting a weak user with the highest correlation coefficient as a weak user in a cluster where the strong user is located, and excluding matched users from respective user groups, until the matching between all strong users and weak users are completed;
• and
• distributing a preset transmit power to each cluster, and distributing a transmit power to strong users and weak users in the cluster, wherein a power distribution factor an, 1 of the strong users satisfies the following power distribution conditions:
• max
• α
• n
• ,
• 1
• (
• R
• n
• ,
• 1
• +
• R
• n
• ,
• 2
• )
• s
• .
• t
• .
• R
• n
• ,
• 1
• ≥
• R
• n
• 1
• ,
• conv
• -
• BF
• R
• n
• ,
• 2
• ≥
• R
• n
• 2
• ,
• conv
• -
• BF
• 0
• ≤
• α
• n
• ,
• 1
• ≤
• 1
• ,
• wherein Rn,1 is a data rate of strong users in a cluster n, Rn,2 is a data rate of weak users in the cluster n;
• Rn1,conv-BF is a rate threshold of strong users in a MIMO-OMA system under the same conditions, and Rn2,conv-BF is a rate threshold of weak users in the MIMO-OMA system under the same conditions.