阅读说明：本技术 基站侧自适应混合预编码系统和混合预编码的设计方法 (The design method of base station side ADAPTIVE MIXED pre-coding system and mixing precoding ) 是由 秦启波 归琳 张凌 于 2018-05-21 设计创作，主要内容包括：本发明提供了一种基站侧自适应混合预编码的方案,其中每个射频链固定连接到部分移相器,每个移相器通过选择开关自适应连接到单根天线。针对该结构,设计射频预编码矩阵使等效信道增益最大,设计基带预编码矩阵消除多用户间的干扰。本发明减少了多用户Massive MIMO系统中的移相器数目的需求,降低了硬件开销,同时使系统的频谱效率接近全连接结构的频谱效率。(The present invention provides a kind of schemes of base station side ADAPTIVE MIXED precoding, wherein each rf chain is fixedly attached to part phase shifter, each phase shifter passes through selection switch adaptive connection to single antenna.For the structure, designing radio frequency pre-coding matrix keeps equivalent channel gain maximum, and design base band pre-coding matrix eliminates the interference between multi-user.The present invention reduces the demands of the phase shifter number in multi-user's Massive mimo system, reduce hardware spending, while making the spectrum efficiency of system close to the spectrum efficiency of full connection structure.)

1. a kind of base station side ADAPTIVE MIXED pre-coding system, which is characterized in that the mixing pre-coding system includes N_tRoot emits day Line number, N_RFA rf chain and N_tA phase shifter, each rf chain are connected with M phase shifter, and each phase shifter passes through selection switch It is connected to single transmitting antenna, wherein M=N_t/N_RF。

2. the mixing method for precoding of base station side ADAPTIVE MIXED pre-coding system according to claim 1, feature exist In this method comprises the following steps:

1. designing radio frequency pre-coding matrix:

Wherein,For radio frequency pre-coding matrix, * is conjugate operation, for 1≤k≤K,Indicate kth The corresponding channel vector of a user；For K+1≤k≤N_RF, h_kIndicate h_mo_d(k-1_,K)+1, mod is complementation operation, and K indicates system The number of users accessed simultaneously with frequency,It indicates a set containing M element, is denoted as:

Wherein,Indicate vector | h_k| the indexed set that middle all elements arrange in descending order, It indicates to be rounded downwards；

2. designing base band pre-coding matrix are as follows:

Wherein,For base band pre-coding matrix,For equivalent matrix,

According to F_BObtain the reception signal of K user are as follows:

Wherein,Indicate transmitting signal.From the above equation, we can see that the base band pre-coding matrix of design is done between can eliminating user It disturbs.

3. according to the F acquired_RFInstruct the value of phase shifter and the connection of switch in precoding network: for kth (1≤k≤ N_RF) a radio frequency chain link M phase shifter, be set to F from top to bottom_RFThe value of M nonzero element in (:, k)；M_k(1≤ m_k≤ M) a phase shifter by switch is connected to theRoot antenna, whereinIndicate F_RFM in (:, k)_kIt is a non- Line number where zero.

Technical field

The present invention relates to wireless communication technique, especially a kind of base station side ADAPTIVE MIXED pre-coding system and mixing prelist The design method of code.

Background technique

Extensive multiple-input and multiple-output (Massive Multi-input Multi-output, hereinafter referred to as Massive MIMO) in system, base station side installs hundreds and thousands of antennas, multiple users can be serviced on identical running time-frequency resource, by filling Divide and utilize space resources, spectrum efficiency and power efficiency can be greatly improved, become one of crucial candidate technologies of 5G.

Pre-coding scheme can be prelisted using digital precode, simulation precoding or mixing in Massive mimo system Code.Wherein, corresponding radio frequency (Radio Frequency, the RF) chain of every antenna, system have very in digital precode structure Good performance, however structure is complicated for digital precode, to hardware requirement height, and power consumption is big；Simulation precoding passes through shifting The control of phase device sends the phase of signal, overcomes digital precode disadvantage at high cost, however simulate precoding can not provide it is more The gain of road multiplexing；In order to weigh system performance and hardware cost, pre-coding scheme quilt in Massive mimo system is mixed It accepts extensively, mixing precoding combines digital precode and simulation precoding structure, supports multichannel number using a small amount of RF chain According to transmission.

Currently, common mixing precoding structure includes full connection structure and sub- connection structure.For full connection structure, often Root antenna is connected with all RF chains by phase shifter, thus system needs a large amount of phase shifter, and hardware spending is still larger.For Sub- connection structure, each rf chain is fixedly attached to part phase shifter, and each phase shifter is only fixedly connected with an antenna, right The demand of phase shifter number substantially reduces, and reduces hardware cost.However, existing literature shows that sub- connection structure imitates frequency spectrum Rate loss is larger.Therefore, mixing precoding structure how is designed, hardware cost expense and system spectral efficiency is combined, is One urgent problem to be solved.

Summary of the invention

For the defects in the prior art, the purpose of the present invention is to propose to a kind of mixing precoding structures and corresponding mixing Precoding algorithms combine the spectrum efficiency of hardware cost and system.

Technical solution of the invention is as follows:

A kind of base station side ADAPTIVE MIXED pre-coding system, it is characterized in that, which includes N_tRoot hair Penetrate antenna number, N_RFA rf chain and N_tA phase shifter, each rf chain are connected with M phase shifter, and each phase shifter passes through selection Switch is connected to single transmitting antenna, wherein M=N_t/N_RF, system is simultaneously K, each user configuration with the number of users of frequency access Single antenna.

The mixing method for precoding of above-mentioned base station side ADAPTIVE MIXED pre-coding system, includes the following steps:

1. designing radio frequency pre-coding matrix:

Wherein,For radio frequency pre-coding matrix, * is conjugate operation, for 1≤k≤K,It indicates The corresponding channel vector of k-th of user；For K+1≤k≤N_RF, h_kIndicate h_mod(k-1,K)+1, mod is complementation operation, and K indicates system The number of users that system is accessed with frequency simultaneously,It indicates a set containing M element, is denoted as:

Wherein,Indicate vector | h_k| the indexed set that middle all elements arrange in descending order, Indicate to Lower rounding.

2. designing base band pre-coding matrix are as follows:

Wherein,For base band pre-coding matrix,For equivalent matrix,

According to F_BObtain the reception signal of K user are as follows:

Wherein,Indicate transmitting signal.From the above equation, we can see that the base band pre-coding matrix of design can eliminate user Between interfere.

3. according to the F acquired_RFInstruct the value of phase shifter and the connection of switch in precoding network: for kth (1 ≤k≤N_RF) a radio frequency chain link M phase shifter, be set to F from top to bottom_RFThe value of M nonzero element in (:, k)；M_k (1≤m_k≤ M) a phase shifter by switch is connected to theRoot antenna, whereinIndicate F_RFM in (:, k)_k Line number where a nonzero value.

By above step, available radio frequency pre-coding matrix and base band pre-coding matrix and guide precoding network The value of middle phase shifter and the connection of switch, realize the Precoding Design of mixed structure.

Compared with prior art, beneficial effects of the present invention:

1, since in connection system entirely, each rf chain is connected with all antennas by phase shifter, system needs a large amount of Phase shifter, and it is proposed that ADAPTIVE MIXED pre-coding system in each rf chain only pass through a small amount of phase shifter and be connected to day Line, effectively reduces the number of phase shifter, to reduce hardware cost；

2, due to designing radio frequency pre-coding matrix according to channel vector, radio frequency pre-coding matrix and channel vector is maximum M element matching, can be improved the gain of equivalent channel, to improve the spectrum efficiency of system.

Detailed description of the invention

Fig. 1 is the structural schematic diagram of ADAPTIVE MIXED pre-coding system of the present invention, F_RFIt is hardware configuration, F_BSoftware can be passed through It realizes.Wherein, (1) indicates phase shifter, and (2) indicate switch, and (3) indicate antenna.

Fig. 2 system spectral efficiency performance comparison schematic diagram

Specific embodiment

The present invention will be further described with reference to the accompanying drawings and examples.The present embodiment is with technical solution of the present invention Premised under implemented, the detailed implementation method and specific operation process are given, but protection scope of the present invention is unlimited In following embodiments.

In multi-user's Massive MIMO downlink communication, the structure of ADAPTIVE MIXED pre-coding system of the present invention is such as Shown in Fig. 1, different mixed structures are as shown in table 1 to phase shifter number demand.

Structure	Full connection	The adaptive connection of proposition	Son connection
				Phase shifter number	NtNRF	Nt	Nt

The phase shifter number demand of 1 different structure of table

Base station side of the invention mixes Precoding Design method.Steps are as follows:

1, the present embodiment ADAPTIVE MIXED precoding structure.Wherein, base station side configuration originator antenna number is N_t=128, it penetrates Frequency chain number is N_RF=8, phase shifter number is N_t=128, each rf chain is fixedly attached to M=16 phase shifter, Mei Geyi Phase device passes through selection switch adaptive connection to single transmitting antenna；System is simultaneously K=4 with the number of users of frequency access, each User configuration single antenna.

2, ADAPTIVE MIXED precoding algorithms of the present invention, including design radio frequency pre-coding matrix make equivalent channel gain most Greatly, design base band pre-coding matrix eliminates the interference between multi-user.Specifically comprise the following steps:

1. radio frequency pre-coding matrix design is as follows:

WhereinFor radio frequency pre-coding matrix, * is conjugate operation, for 1≤k≤4,Indicate the The corresponding channel vector of k user；For 5≤k≤8, h_kIndicate h_mo_d(k-1_,4)+1, mod is complementation operation.One is indicated to contain The set of 16 elements, is denoted as:

WhereinIndicate vector | h_k| the indexed set that middle all elements arrange in descending order, Indicate to Lower rounding.

2. base band pre-coding matrix design is as follows:

Wherein,For base band pre-coding matrix,For equivalent matrix,

According to F_BObtain the reception signal of 4 users are as follows:

Wherein,Indicate transmitting signal.From the above equation, we can see that the base band pre-coding matrix of design can eliminate user Between interfere.

3. according to the F acquired in 1._RFInstruct the value of phase shifter and the connection of switch in precoding network: for 16 phase shifters of a radio frequency chain link of k (1≤k≤8), are set to F from top to bottom_RFThe value of 16 nonzero elements in (:, k)； M_k(1≤m_k≤ 16) a phase shifter is connected to the by switchRoot antenna, whereinIndicate F_RF(:, K) m in_kLine number where a nonzero value.

By above step, available radio frequency pre-coding matrix and base band pre-coding matrix and guide precoding network The value of middle phase shifter and the connection of switch, realize the Precoding Design of mixed structure.

The spectrum efficiency performance comparison of ADAPTIVE MIXED pre-coding scheme and conventional hybrid pre-coding scheme of the invention is such as Shown in Fig. 2.As it can be seen that the present invention effectively increases the spectrum efficiency of system compared to son connection, and performance levels off to the property connected entirely Energy.