CN106160809A - The mixing method for precoding of multi-user multi-aerial system and device thereof - Google Patents

Abstract

The present invention is the mixing method for precoding and device thereof with regard to multi-user multi-aerial system.According to one embodiment of the invention, the method for a hybrid analog-digital simulation/digital precode being used for multi-user's antenna system comprises N_TRoot antenna is divided into L group；It is S data stream by K data streaming digital precoding；Phase-shift network is configured to L sub-phase-shift network of mutual signal isolation, and this L sub-phase-shift network is corresponding with this L group antenna respectively；Wherein this phase-shift network comprises S the radio frequency link receiving each in this S data stream respectively, and each in this L sub-phase-shift network comprises at least one in this S radio frequency link further；And the output by each radio frequency link in each sub-phase-shift network maps to each antenna wherein N in respective antenna group_T, S, K, L be integer more than 1, NT >=S >=K, and S >=L.The present invention can active balance multi-user's antenna system complexity and performance.

Description

The mixing method for precoding of multi-user multi-aerial system and device thereof

Technical field

The present invention is with regard to multi-user multi-aerial system, especially with regard to the hybrid analog-digital simulation/numeral of multi-user multi-aerial system Method for precoding and device thereof.

Background technology

In multi-user's antenna system, mixing precoding technique by by segment space signal transacting from base band sidesway to penetrating Frequently the number of radio-frequency path is reduced in front end, can effectively reduce the cost, hard arranged radio-frequency path (RF path) and brought Part complexity and power consumption.Although and spatial multiplexing gain is limited by the number of radio-frequency path in theory, mixing precoding skill Art still can obtain complete diversity gain and array gain by suitable processing.

Simulation precoding dependence in mixing precoding is penetrated simulation phase network and is realized.But, at current mixing precoding Reason method and apparatus is difficult to obtain good balance, one between the two in complexity and the precoding performance of analog phase-shift network Still exchange high-performance for complicated analog phase-shift network, though and the complexity that another one reduces analog phase-shift network cannot Obtain good performance.

Therefore, still need in the industry make great efforts to improve existing mixing precoding technique.

Content of the invention

An object of the present invention is to provide the hybrid analog-digital simulation/digital precode method of a multi-user multi-aerial system and dress Put, its take into account the complexity of enforcement and performance without be partial to arbitrary extremely.

One embodiment of the invention provide one for multi-user multi-aerial system mixing precoding method, its comprise by N_TRoot antenna is divided into L group；It is S data stream by K data streaming digital precoding；Phase-shift network is configured to each other L sub-phase-shift network of signal isolation, this L sub-phase-shift network is corresponding with this L group antenna respectively；Wherein this phase shift net Network comprises S the radio frequency link receiving each in this S data stream respectively, each in this L sub-phase-shift network Comprise at least one in this S radio frequency link further；And the output by each radio frequency link in each sub-phase-shift network Map to each antenna wherein N in respective antenna group_T, S, K, L be integer more than 1, N_T>=S >=K, and S >=L.

In one embodiment, N_TMore than 2.Perform broadband analogue precoding in this each sub-phase-shift network, at this L Narrow-band digital precoding is performed between sub-phase-shift network；With C_lRepresent the broadband analogue pre-coding matrix that l (1-L) organizes, B_wRepresent the digital precode matrix on w-th subcarrier, then whole precoding processing is expressed as:

Wherein y_wIt is K × 1 vector being received by K user equipment antenna on this w-th subcarrier, H_wBe this K × N on all user equipment antennas on w subcarrier_TChannel vector, x_wThis w-th subcarrier transmits K × 1 data vector, and n_wIt is additive white Gaussian noise.C_lCan be by transmitting correlation matrixObtain through calculated below:

FromExtract (the N of corresponding l group antenna_T/L)×(N_T/ L) submatrixThen performSingular value decomposition (Singular Value Decomposition) obtainsWherein U_lIt is unitary matrice, Λ_lIt is diagonal matrix, its diagonal angle Element is descendingSingular value, C_l=U_l(:, 1:S/L), U_l(:, 1:S/L) represent by U_lFirst to S/L row composition Submatrix.

In one embodiment, the user that this each sub-phase-shift network is serviced by this broadband precoding uses the greediness of iteration to search Suo Fangfa, it comprises:

In each iteration, access this L sub-phase-shift network and a user equipment is at most increased to this each sub-phase-shift network To its served user equipment list；Start with p=0 iteration, wherein any l. value is initializedC_l=0；Wherein κ_l Represent the indexed set of the user equipment that l group services；This each iteration comprises L sub-iteration, by the q (q of pth time iteration =1～L) individual sub-iteration be denoted as (p, q) secondary iteration, if q < L, can be moved to (p, q+1) secondary iteration, when q=L then Can be moved to (p+1,1) secondary iteration；At (p, q) secondary iteration, the κ in iteration before only changing_qWith C_qAnd keep { κ_l, l ≠ q} with {C_l, l ≠ q} is constant；When in this L sub-phase-shift network, anyone does not all have new user equipment to add, iteration stopping.

This κ_qAnd C_qModification be by search all have index k ∈ υ κ_qUser equipment, υ all users in representing cell Equipment collection；To each user equipment k ∈ υ κ_q, regenerate corresponding κ_qThe C of ∪ k_q, and calculate the average of corresponding efficient channel Capacity, then selects the user equipment k* of a maximum mean capacity with efficient channel, if corresponding κ_qThe capacity of ∪ k* is more than Corresponding κ_qCapacity, then k* is added κ_q.In one embodiment, by this N_TRoot antenna mean allocation to L group, and In another embodiment, this non-average mark of NT root antenna is assigned to L group.

One embodiment of the invention additionally provides a base station, and it comprises the NT root antenna being configured to be divided into L group, is configured It with the baseband precoder being S data stream by K data streaming digital precoding, and is configured to comprise to receive this S respectively The phase-shift network of S radio frequency link of each in individual data stream.This phase-shift network is further configured to L sub-phase-shift network and divides Not corresponding with this L group antenna, wherein NT, S, K, L are the integer more than 1, NT >=S >=K, and S >=L.This L Each in sub-phase-shift network comprises at least one in this S radio frequency link further, each in each sub-phase-shift network penetrates The output of frequency link maps to signal isolation between each antenna in respective antenna group, and this L sub-phase-shift network.

In one embodiment, this each sub-phase-shift network farther includes power splitter, is configured in this each sub-phase-shift network The output of each radio frequency link is divided into multichannel；Phase shifter, is configured to the output of each road to this power splitter and carries out phase shift；With And combiner, it is configured to merge the output of the corresponding same antenna of this phase shifter.

Mixing method for precoding and device that the embodiment of the present invention provides can be clever according to the concrete requirement of multi-user's antenna system Live and adjust the setting of system complexity and performance, thus allow current multi-user multiaerial system to select most suitable complexity And systematic function.

Brief description

It is a structural representation typically mixing pre-coding apparatus shown in Fig. 1；

It is another structural representation typically mixing pre-coding apparatus shown in Fig. 2；

It is the structural representation mixing pre-coding apparatus according to an embodiment of the invention shown in Fig. 3；

Fig. 4,5 demonstrate respectively when according to one embodiment of the invention the planar antenna array of 8*8 being divided into 4 groups not Same group technology.

Detailed description of the invention

Spirit for a better understanding of the present invention, it is made furtherly by the part preferred embodiment below in conjunction with the present invention Bright.

In mixing precoding technique, simulation precoding typically uses what analog phase-shift network realized, and phase-shift network Complexity depends on the concrete framework simulating precoding processing device.

For example, it shown in Fig. 1 is a structural representation typically mixing pre-coding apparatus 10.Mixing precoding dress Putting 10 and may be disposed at the base station (not shown) with N root antenna 12, N is the integer more than 1.As it is shown in figure 1, it is mixed Close pre-coding apparatus 10 and comprise baseband precoder 14 and phase-shift network 16.Phase-shift network 16 comprises S radio frequency link (RF chain) 160, wherein S is the integer more than or equal to 1 and less than or equal to N.Each radio frequency link 160 defeated Go out by power splitter 162 decompose, again the phase shift of shifted device 164 and map to all N root antennas 12, and each antenna 12 On the signal of all S the radio frequency links 160 receiving be superimposed transmission by combiner 166.Visible mixed at this Closing in pre-coding apparatus 10, phase-shift network 16 needs to arrange the full mapping that S*N radio-frequency path 168 realizes signal.Should Mixing pre-coding apparatus 10 exchanges the performance of optimum for hardware configuration the most complicated.

It is another structural representation typically mixing pre-coding apparatus 20 shown in Fig. 2.Mixing pre-coding apparatus 20 can set Being placed in the base station (not shown) with N root antenna 22, N is the integer more than 1.As in figure 2 it is shown, mixing precoding Device 20 comprises baseband precoder 24 and phase-shift network 26.Phase-shift network 26 comprises S radio frequency link 260, its Middle S for the integer more than or equal to 1 and less than or equal to N and simple for the sake of set the integral multiple that N is S.This N root antenna 22 It is divided into S group.The output of each radio frequency link 260 is decomposed into N/S, more shifted device 264 by power splitter 262 and moves Map to mutually transmit on each antenna 22.Visible in this mixing pre-coding apparatus 20,26 need of phase-shift network Arrange N number of radio-frequency path 268.This mixing pre-coding apparatus 20 has simplest structure, but performance is poor Strong man anticipates.

The embodiment of the present invention provide mixing method for precoding and device then can according to system requirements be adjusted flexibly complexity and The relation of performance, the advantage having above two structure concurrently, and the shortcoming reducing both as far as possible.Simulation result shows, this The mixing precoding technique that inventive embodiments provides, relative to prior art, is reduced to structure shown in Fig. 1 at hardware complexity Half in the case of performance only lose 4%；And hardware complexity be reduced to structure shown in Fig. 1 1/4th situation The also only loss 12% of lower performance.

It is the structural representation mixing pre-coding apparatus 30 according to an embodiment of the invention shown in Fig. 3.

As it is shown on figure 3, this mixing pre-coding apparatus 30 may be disposed on the (not shown) of base station, this base station is provided with N_TRoot antenna 32, N_TIt for the integer more than or equal to 1, is preferably more than 2.In the present embodiment, setting for the sake of simple should Base station is that K single-antenna subscriber devices (not shown) sends down link data, and K is the integer more than or equal to 1.? In other embodiments, user equipment is not single antenna yet, has no effect on the essence place of the present invention.

This mixing pre-coding apparatus 30 comprises baseband precoder 34 and phase-shift network 36.Phase-shift network 36 comprises S Radio frequency link 360, N_T≥S≥K.By N_TRoot antenna 32 mean allocation or non-average mark can be made into L group, S >=L, group with There is no signal exchange between the antenna 32 of group.Accordingly, this phase-shift network 36 is further configured to L sub-phase-shift network 360, each sub-phase-shift network 360 and one group of antenna 32 one_to_one corresponding.It is similar to, also do not have between sub-phase-shift network 360 There is signal communication.In the present embodiment, for the sake of simplicity, set N_T, S be that the integral multiple of L is with by N_TRoot antenna 32 and S Individual radio frequency link 361 is divided into L group, often has N in group_T/ L root antenna 32 and S/L radio frequency link 361.For example, Fig. 4,5 differences demonstrating respectively when the planar antenna array of 8*8 being divided into 4 groups according to one embodiment of the invention are divided Prescription method, often has 16 antennas 32 in group, different pattern represents different packets.These different group technologies are in sky Line number N_TImpact can't be produced on the essence of the present invention when determining with packet count L.For sky in often group this in Fig. 5 The staggered situation in line 32 position, can use antenna mapping device to realize that the output of each sub-phase-shift network 360 is right with any antenna 32 The design answered.

When base station is intended to K user device transmissions K the data being serviced, this K data stream is first through the number of base band Word precoding processing device 34 is processed as S data stream, and this S data flow point you can well imagine S radio frequency link 361 of supply.Often One sub-phase-shift network 360 comprises S/L radio frequency link the 361st, S/L power splitter the 363rd, SN/L²Individual phase shifter 335 and S/L combiner 367.In each sub-phase-shift network 360, the output of each radio frequency link 361 is by power splitter 363 Resolve into N_T/ L road and decompose shifted device 365 phase shift of Hou Ge road signal to be respectively supplied to should sub-phase-shift network The N of 360_T/ L root antenna.For an antenna for base station 32, it receives owning in corresponding sub-phase-shift network 360 The signal that S/L radio frequency link 361 provides, these signals are transmitted to user by this antenna 32 again through combiner 367 superposition Equipment.That is, the present invention achieves the performance requirement of maximum to the antenna 32 in each group.Simultaneously because have employed packet The method processing, does not has signal communication between group and group, overall phase-shift network 36 controls at SN/L radio-frequency path, Can be much smaller than SN radio-frequency path during full mapping by the value controlling L.

The embodiment of the present invention additionally provides mixing method for precoding, and it can be held mixing pre-coding apparatus 30 as shown in Figure 3 OK.Spatial signal processing is divided into broadband analogue precoding and narrow-band digital precoding, wherein at each sub-phase-shift network 360 Interior execution is simulated precoding and is combined execution digital precode between L sub-phase-shift network 360.

Concrete, for having N_FFTFor the downlink of the extensive mimo system of individual subcarrier, use the time-division Multiplexing is so that base station can obtain channel condition information in up-link detection.Based on aforementioned setting, it is assumed that l group defeated Going out to be mapped to index is (l-1) N_T/ L+1～lN_TThe antenna of/L.h_k,wIt is that k-th user equipment is on w-th subcarrier N_T× 1 dimension frequency domain channel vector.According to Kronecker (Kronecker) channel model, available

$h_{k,w}={\left(R_k^{\left(t\right)}\right)}^{1/2}{h}_{k,w}^{\left(\mathrm{iid}\right)}---\left(1\right)$

WhereinIt is h_k,wTransmitting correlation matrix (transmitter correlation matrix), its It is constant over the whole width, andIt is to comprise independent same distribution (i.i.d, independent identically Distributed) random vector of element.

The user equipment that different transmission cycles, each sub-phase-shift network 360 and corresponding group antenna 32 are serviced may phase With being likely to difference, depend on the scheduling result of base station.With κ_lRepresent l group (each sub-phase-shift network 360 and correspondence Group antenna 32) indexed set of user equipment that services,(without repeating).K_lRepresent κ with K respectively_lBig with κ Little.

With C_lRepresent the broadband analogue pre-coding matrix of l group, B_wRepresent the digital precode matrix on w-th subcarrier, Then whole precoding processing is expressed as:

Wherein y_wBe on w-th subcarrier by K user equipment (user equipment antenna, for single-antenna subscriber devices, User equipment antenna number is equal to user device quantity, lower with) K × 1 vector that receives, H_wIt is that K is individual on w-th subcarrier K × the N of user equipment_TChannel vector, x_wIt is K × 1 data vector of transmission on w-th subcarrier, and n_wIt is that additivity is high This white noise (AWGN).

Simulation pre-coding matrix { C_lAnd digital precode matrix { B_wCan be obtained by separate method, explain individually below

Firstly for simulation precoding, the K of l group_l×N_TChannel matrix is expressed as:

$H_{l,w}={\left[\begin{array}{ccccc}{h}_{{\mathrm{\&kappa;}}_l\left(1\right)}& ...& h_{{\mathrm{\&kappa;}}_l\left(k\right)}& ...& h_{{\mathrm{\&kappa;}}_l\left(K_l\right)}\end{array}\right]}^H---\left(3\right)$

H_l,wTransmitting correlation matrix can be calculated as:

${\stackrel{\&OverBar;}{R}}_l^{\left(t\right)}=E(H_{l,w}^H,H_{l,w})=\underset{k\&Element;{\mathrm{\&kappa;}}_l}{\mathrm{\&Sigma;}}{R}_k^{\left(t\right)}---\left(4\right)$

FromExtract (the N of corresponding l group antenna_T/L)×(N_T/ L) submatrixThen performSingular value decomposition (SVD, singular value decomposition) obtains

${\stackrel{\&OverBar;}{R}}_l^{(t\_s)}=U_l{\mathrm{\&Lambda;}}_l{U}_l^H---\left(5\right)$

Wherein U_lIt is unitary matrice, Λ_lBeing diagonal matrix, its diagonal element is descendingSingular value.

The simulation pre-coding matrix C of l group_lIt is calculated as:

C_l=U_l(:, 1:S/L) (6)

Wherein U_l(:, 1:S/L) represent by U_lFirst to S/L row composition submatrix.

Obtaining simulating pre-coding matrix { C_lThe number calculating each subcarrier based on (precoding after simulation) efficient channel is i.e. can use after } Word pre-coding matrix B_w,

$B_w={\left(H_{w}C\right)}^H{\left(H_{w}C{\left(H_{w}C\right)}^H\right)}^{-1}{P}^{1/2}={\left(H_w^{\left(\mathrm{eff}\right)}\right)}^H{\left(H_w^{\left(\mathrm{eff}\right)}{\left(H_w^{\left(\mathrm{eff}\right)}\right)}^H\right)}^{-1}{P}^{1/2}---\left(7\right)$

Wherein, pre-coding matrix is simulated

It is the efficient channel on w-th subcarrier；And P is diagonal matrix, its diagonal element represents K use The average transmission power of family equipment.

For maximum system performance, the greedy search by group of dispatching user facility when embodiments providing wide simulation precoding Method.

All user equipment collection in representing cell with υ, the broadband method for precoding of the embodiment of the present invention is to different groups, i.e. each sub-shifting Phase network 360 uses the exhaustive search method of iteration.In each iteration, access all of group and each group is at most increased One user equipment is to its served user equipment list.Start with p=0 iteration, wherein any l. value is initialized C_l=0.Each iteration comprises L sub-iteration.The individual sub-iteration of q (q=1～L) of pth time iteration is denoted as the (p, q) secondary Iteration, if q < L, can be moved to (p, q+1) secondary iteration, when q=L then can be moved to (p+1,1) secondary iteration.(p, Q) secondary iteration, by the κ in iteration before only changing_qWith C_qAnd keep { κ_l, l ≠ q} and { C_l, l ≠ q} is constant, and broadband method for precoding is Maximizing efficient channel capacity.κ_qAnd C_qThe modification of value be by search all have index k ∈ υ κ_qUser equipment.Right Each user equipment k ∈ υ κ_q, the broadband method for precoding of the embodiment of the present invention is to κ_qUser equipment in ∪ k uses formula (6) again Produce C_q, and calculate the average size of corresponding efficient channel.Then, the use of the maximum mean capacity with efficient channel is set Family equipment is k*, if corresponding κ_qThe capacity of ∪ k* is more than corresponding κ_qCapacity, then k* is added κ_q.When any group is not all used When family equipment adds, iteration stopping.

The technology contents of the present invention and technical characterstic have revealed that as above, but those of ordinary skill in the art are still potentially based on Teachings of the present invention and announcement and make all replacements without departing substantially from spirit of the present invention and modification.Therefore, the protection model of the present invention Enclose the content should being not limited to disclosed in embodiment, and the various replacement without departing substantially from the present invention and modification should be included, and for this specially Profit application claims are covered.

Claims (15)

1. a method, for the hybrid analog-digital simulation/digital precode of multi-user multi-aerial system；Described method comprises:

By N_TRoot antenna is divided into L group；

It is S data stream by K data streaming digital precoding；

Phase-shift network is configured to L sub-phase-shift network of mutual signal isolation, and described L sub-phase-shift network is corresponding with described L group antenna respectively；Wherein said phase-shift network comprises S the radio frequency link receiving each in described S data stream respectively, and each in described L sub-phase-shift network comprises at least one in described S radio frequency link, wherein N further_T, S, K, L be integer more than 1, N_T>=S >=K, and S >=L；

The output of each radio frequency link in each sub-phase-shift network is mapped to each antenna in respective antenna group.

2. method according to claim 1, wherein N_TMore than 2.

3. method according to claim 1, wherein performs broadband analogue precoding in described each sub-phase-shift network, performs narrow-band digital precoding between described L sub-phase-shift network；With C_lRepresent the broadband analogue pre-coding matrix that l (1-L) organizes, B_wRepresent the digital precode matrix on w-th subcarrier, then whole precoding processing is expressed as:

Wherein y_wIt is K × 1 vector being received by K user equipment antenna on described w-th subcarrier, H_wIt is the K × N on described w-th subcarrier on all user equipment antennas_TChannel vector, x_wIt is K × 1 data vector of transmission on described w-th subcarrier, and n_wIt is additive white Gaussian noise.

4. method according to claim 3, wherein C_lBy transmitting correlation matrixObtain through calculated below:

FromExtract (the N of corresponding l group antenna_T/L)×(N_T/ L) submatrixThen performSingular value decomposition (Singular Value Decomposition) obtainWherein U_lIt is unitary matrice, Λ_lIt is to compriseMiddle diagonal matrix, its diagonal element is descendingSingular value, C_l=U_l(:, 1:S/L), U_l(:, 1:S/L) represent by U_lFirst to S/L row composition submatrix.

5. method according to claim 3, the precoding of wherein said broadband uses the user being serviced described each sub-phase-shift network to use the greedy search method of iteration, and it comprises:

In each iteration, access described L sub-phase-shift network and a user equipment is at most increased to its corresponding served user equipment list to described each sub-phase-shift network；

Start with p=0 iteration, wherein any l. value is initializedC_l=0；WhereinRepresent the indexed set of the user equipment that l group services；

Described each iteration comprises L sub-iteration, and the individual sub-iteration of q (q=1～L) of pth time iteration is denoted as (p, q) secondary iteration, if q < L, can be moved to (p, q+1) secondary iteration, when q=L then can be moved to (p+1,1) secondary iteration；

The, (p, q) secondary iteration, before only changing in iterationWith C_qAnd keepWith { C_l, l ≠ q} is constant；

When in described L sub-phase-shift network, anyone does not all have new user equipment to add, iteration stopping.

6. method as claimed in claim 5, wherein saidAnd C_qModification be all to there is index by searchUser equipment, υ all user equipment collection in representing cell；To each user equipmentRegenerate correspondenceC_q, and calculate the average size of corresponding efficient channel, then select the user equipment k* of a maximum mean capacity with efficient channel, if correspondingCapacity more than correspondenceCapacity, then by k* add

7. the method for claim 1, wherein by described NT root antenna mean allocation to L group.

8. non-for described NT root antenna average mark is wherein assigned to L group by the method for claim 1.

9. a base station, comprises:

N_TRoot antenna, is configured to be divided into L group；

Baseband precoder, being configured to K data streaming digital precoding is S data stream；

Phase-shift network, is configured to S the radio frequency link comprising to receive each in described S data stream respectively；And described phase-shift network to be further configured to L sub-phase-shift network corresponding with described L group antenna respectively, wherein N_T, S, K, L be integer more than 1, N_T>=S >=K, and S >=L；

Each in wherein said L sub-phase-shift network comprises at least one in described S radio frequency link further, the output of each radio frequency link in each sub-phase-shift network maps to signal isolation between each antenna in respective antenna group, and described L sub-phase-shift network.

10. base station as claimed in claim 1, wherein by described NT root antenna mean allocation to L group.

Non-for described NT root antenna average mark is wherein assigned to L group by 11. base stations as claimed in claim 1.

12. base stations as claimed in claim 1, wherein N_TMore than 2.

13. base stations as claimed in claim 1, wherein said each sub-phase-shift network farther includes power splitter, is configured the output by each radio frequency link in described each sub-phase-shift network and is divided into multichannel；Phase shifter, is configured to the output of each road to described power splitter and carries out phase shift；And combiner, it is configured to merge the output of the corresponding same antenna of described phase shifter.

14. 1 kinds of methods, for having the associating multi-subscriber dispatching between L sub-phase-shift network；Described method comprises:

In each iteration, access described L sub-phase-shift network and a user equipment is at most increased to its served user equipment list to described each sub-phase-shift network；

Start with p=0 iteration, wherein any l. value is initializedC_l=0；WhereinRepresent the indexed set of the user equipment that l group services, C_lRepresent the broadband analogue pre-coding matrix that l (1-L) organizes；

Described each iteration comprises L sub-iteration, and the individual sub-iteration of q (q=1～L) of pth time iteration is denoted as (p, q) secondary iteration, if q < L, can be moved to (p, q+1) secondary iteration, when q=L then can be moved to (p+1,1) secondary iteration；

The, (p, q) secondary iteration, before only changing in iterationWith C_qAnd keepWith { C_l, l ≠ q} is constant；

When in described L sub-phase-shift network, anyone does not all have new user equipment to add, iteration stopping.

15. methods as claimed in claim 15, wherein saidAnd C_qModification be all to there is index by searchUser equipment, υ all user equipment collection in representing cell；To each user equipmentRegenerate correspondenceC_q, and calculate the average size of corresponding efficient channel, then select the user equipment k* of a maximum mean capacity with efficient channel, if correspondingCapacity more than correspondenceCapacity, then by k* add。