WO2015161397A1

WO2015161397A1 - User equipment pairing method and apparatus in multi-user mimo

Info

Publication number: WO2015161397A1
Application number: PCT/CN2014/000442
Authority: WO
Inventors: 尤明礼; 尚鹏
Original assignee: 上海贝尔股份有限公司
Priority date: 2014-04-24
Filing date: 2014-04-24
Publication date: 2015-10-29
Also published as: CN106031279A

Abstract

The present invention relates to a user equipment pairing method and apparatus in multi-user MIMO. According to an embodiment of the present invention, a pairing method in multi-user MIMO comprises: receiving a wireless location of a user equipment in a wireless network; characterizing the wireless location of the user equipment as interference; and using the interference to weight a pairing matrix in multi-user MIMO, and/or using the interference to control the number of user equipments paired in the multi-user MIMO, which can better balance the total capacity and the total interference in multi-user MIMO, thereby optimizing the capacity of a wireless network. The present invention can solve the inter-cell or inter-cluster interference problem in multi-user MIMO, and improve the throughput of the system.

Description

Pairing method and device for user equipment in multi-user multi-input and multi-output (MIMO)

The present invention relates to a method and apparatus for pairing user equipment in multi-user multiple input and multiple output (MIM0).

Background technique

In the development of Long Term Evolution (LTE) and Long Term Evolution (LTE-Advanced) projects, MU-MIMO (Multi-User-Multiple Inputs Multiple Outputs) is the most One of the key technologies that can be used to improve the capacity of wireless network systems through spatial multiplexing is widely used in the future.

Specifically, the advanced multi-user-multiple-input and multi-output mainly includes two types: one is a single cell (Single cell), multiple inputs and multiple outputs, and the other is multi-point cooperation (CoMP, Coordinated Multi-Point). . LTE or LTE-A wireless networks using these two multi-input and multi-output methods have serious inter-cell interference or co-cluster (CoMP c 1 uster ) interference problems, and it is difficult to pass the current limited loop (backhau 1) Signaling to reduce interference is solved. For example, traditional semi-static inter-cell interference control or improved inter-cell interference control with X2 signaling is based on long-term measurement of interference ratio (IoT), and is not directly related to multi-user-multiple-input and multi-out. On the other hand, in addition to the strict limitations of measuring the interference link and the loop bandwidth delay and computational complexity, the developing multi-point cooperation technology also has serious inter-cluster interference problems. Currently, there is no multi-point cooperation. Any technical solution for residual inter-cluster interference.

Therefore, how to effectively solve the inter-cell or cluster (CoMP cluster) interference problem in multi-user-multiple-input and multi-out is one of the important tasks in the development of LTE/LTEA projects. Summary of the invention

One of the objects of the present invention is to provide a multi-user-multiple-input and multi-out user equipment pairing method and apparatus to solve the interference problem in a multi-user-multiple-input and multi-out wireless network.

A multi-user-multiple-input and multiple-out pairing method according to an embodiment of the present invention includes: receiving a wireless location of a user equipment in a wireless network; characterizing interference with a wireless location of the user equipment; and using the interference weighted multi-user- Multi-input and multi-out matrices, and/or use the interference to control the number of user devices paired in the multi-user-multiple-input and multi-out The combined capacity of the paired user equipment is below a interference-related combined capacity threshold.

In an embodiment, the interference characterized by the radio location of the user equipment is a path loss of a cell where the user equipment is located, a path loss of a cell where the user equipment is located, and a path loss of a neighboring cell, or a multipoint cooperation. The equivalent path loss of the coordinated cells. The weighting value of the interference weighted multi-user-multiple-input-multiple-pairing matrix is used, and the interference-dependent threshold of using the interference control for the number of user equipments paired in the multi-user-multiple-input and multi-output is a linear function using path loss β (PL,) get,

0. PL, <= PL„

Ττ _ ρτ

( ' ) * a, PL ₀ < PL, <= PL,

PL, - PL _C

a. PL, < PL where 0 ≤ a ≤ 1, PLi is the path loss, PL of the link between the user equipment and its serving base station ί. It is the lower threshold of the path loss, PL, which is the upper threshold of the path loss. In another embodiment, when the interference weighted multi-user-multiple multi-homing pairing matrix is used, further included in a serving cell/cluster, the serving base station calculates and measures all channel state information of the intra-cluster cell from its serving user equipment; A typical multi-user-multiple-input multi-out pairing strategy calculates the sum or increased capacity of paired additional user equipment; and selects the user equipment with the largest weighted increase in fairness until the maximum total capacity or maximum number of streams or users is reached. In an embodiment, using ^: Ι ^Λ控制控制该该控制控制控制控制控制控制控制控制控制控制控制控制控制控制控制控制控制控制控制控制控制控制控制控制控制控制控制控制控制控制控制控制控制控制^控制 The interference dependent threshold is calculated to determine if the appropriate user equipment/flow can be paired. In another embodiment, when the interference is used to control the number of user equipments paired in the multi-user-multiple-input-multiple-out, the method further comprises calculating a proportional fairness of the user equipment/flow and comparing the interference to the interference-dependent threshold. .

Embodiments of the present invention also provide a multi-user-multiple-input multiple-out pairing device, including: a receiving device configured to receive a wireless location of a user equipment in a wireless network; an interference characterization device configured to the user equipment Wireless location characterization interference; and pairing device configured to use the interference weighted multi-user-multiple-input multiple-out matrix, and/or use the interference to control the number of user devices paired in the multi-user-multiple-input-multiple-out The total interference of the paired user equipment is below an interference threshold.

The present invention can maximize multi-user-multiple-input and multi-out capacity based on prior knowledge of channel state information of a serving cell or cluster, and minimize inter-cell interference causing capacity degradation of its neighboring cells or clusters, and between the two Get balanced. Thereby reducing inter-cell interference or inter-cluster interference, and submitting the throughput of the system. DRAWINGS

1 is a graph of a linear function of path loss in accordance with an embodiment of the present invention.

2 is a schematic diagram of a single-cell multi-user-multiple-input and multiple-out scenario according to an embodiment of the invention;

FIG. 3 is a schematic diagram of a multi-point coordinated multi-user multi-input and multiple-out scenario according to an embodiment of the invention;

4 is a schematic structural diagram of a multi-user-multiple-input multiple-output pairing device according to an embodiment of the invention

detailed description

For a better understanding of the spirit of the invention, it will be further described in conjunction with the preferred embodiments of the invention.

As is known to those skilled in the art, the joint processing of multi-user-multiple-input and multi-inter-cell interference is not a simple problem, because it requires not only the service signal link used in the conventional multi-user-multiple input and multiple output. Prior knowledge also requires prior knowledge of the interfering link. More importantly, in addition to the application of these prior knowledge, other potential problems need to be overcome, for example, even the channel state information of the interfering link cannot be obtained.

Unlike the service link, there is no ideal loop, and the interfering link is considered to be a "white" link in the serving cell/cluster without its a priori channel state information. The so-called "service link" refers to the link between the user equipment and the base station it serves, and the "interference link" refers to the link between the user equipment and the non-serving base station. In addition, there is no channel state information that interferes with the link, and there is no tractable joint signal model for the service link and the interference link from the same user equipment, and the corresponding complex signal processing does not help much.

In response to the above problems, the present invention proposes a novel fractional-on-user multi-user-multiple-input and multi-output technique for LTE and LTE-A uplinks, which uses the radio equipment of the user equipment. "White" interference is characterized. Despite the lack of instant channel information in the serving cell, interference can still be well estimated by using long term wireless locations. Therefore, the present invention can maximize the multi-user-multiple-input and multi-output capacity (sum ut ili ty) based on the prior knowledge of the channel state information (CSI, Channel State Interference) of the serving cell or cluster, and minimize the neighboring cell or cluster. The capacity of the recession is inter-cell interference and strikes a balance between the two.

For example, in accordance with an embodiment of the present invention, a multi-user-multiple-input multi-output pairing method includes: receiving a wireless location of a user equipment in a wireless network; characterizing the interference with the wireless location of the user equipment; and using the interference weighting Multi-user-multiple-input-multiple-pairing matrix, and/or using the interference to control the number of user devices paired in the multi-user-multiple-input-multiple-out, so that the combined user equipment has a lower capacity (sum uti l ity ) lower than one The interference-related combined capacity threshold, which is related to the interference of the paired user equipment. The so-called "pairing" is generally referred to by a person skilled in the art as a base station. Selecting multiple user equipment services on the same time-frequency resource, and selecting the multiple user equipments is "pairing". The so-called "capacity" can also be called "utility function".

The interference characterized by the radio location of the user equipment is the path loss of the cell where the user equipment is located, the path loss of the cell where the user equipment is located, and the path loss of the neighboring cell, or the equivalent of multiple coordinated cells in the multi-point cooperation. Path loss. The path loss may be characterized by the user equipment measuring the downlink cell reference signal (CRS) received power (RSRP) of the cell, or by measuring the uplink sounding reference signal (SRS).

When using the interference weighted multi-input and multi-output pairing matrix, the closer the user equipment is to the cell center, the higher the priority is paired; conversely, the closer the user equipment is to the cell edge, the lower the priority is paired. Since the user equipment will have different capacity and interference balances at different radio locations in the wireless network, an interference can be used, such as a fractional function characterized by path loss.

1 is a graph of a linear function of path loss in accordance with an embodiment of the present invention. In this embodiment, the weighting value (e.g., lp(PL)) is obtained based on the linear function p(PL) of the interference using the path loss, and the linear function β(Ρ is specifically expressed as Equation (1). α ≤ 1, α is used for balance capacity and interference contribution. It can be used to adjust the contribution of multi-user multiple input multiple output to capacity and interference, and is the path loss of the user equipment and its serving base station i. The lower threshold of the path loss, PL, is the upper threshold of the path loss, and PL, PL, and ci can be set by those skilled in the art according to actual network conditions and design requirements.

p(PL,) = PL, ; (1)

',

2 is a schematic diagram of a single-cell multi-user-multiple-input and multiple-out scenario according to an embodiment of the invention. In Figure 2, the different cell bands of the application equations (1) in which the different user equipment UEh, UE IJE2, UE3 are located in the cell served by the base station eNB_A are clearly demonstrated.

Furthermore, in conjunction with the scenario of Figure 2, a more detailed multi-user-multiple-input multiple-out pairing embodiment using an interference weighted pairing matrix can be described as follows: At the serving cell/cluster, the serving base station eNB_A measures all channels from its serving user equipment status information. A typical multi-user-multiple-input multi-out pairing strategy is used to calculate the sum or incremental serving utility of any additional service user equipment. For example, the first user equipment, such as the user equipment UEh, may be selected based on the rumor quality, and then another user equipment UE1, UE2 or UE3 is selected for pairing, and then the sum or addition of the other user equipment UE1, UE2 or UE3 is calculated. Capacity, such as proportional fairness. In addition, the radio location of the user equipment UE1, UE2 or UE3 is also measured or collected, such as the path loss to the serving cell/cluster or the path loss difference to the neighboring cell/cluster, and based on this equation (1) The weighted value is calculated, and the weighted value is weighted by the increased service capacity, such as the increased proportion of fairness. Finally, the user equipment with the largest weighted increased service capacity, such as UE2, is selected until the maximum total capacity (combined capacity) or maximum flow is reached.

FIG. 3 is a schematic diagram of a multi-point coordinated multi-user multi-input and multiple-out scenario according to an embodiment of the invention. In this embodiment, the path loss is measurable as a path loss PL _ft to the serving cluster, which may be a measure of the total path loss to all cells in the cluster, ie, as in equation (2) The equivalent path loss is shown, where K is the total number of cells in a cluster. Each cell has the arrangement scenario shown in Figure 2, and will not be described again.

(2)

When using interference to control the number of user equipments paired in multi-user-multiple-input and multi-out, similarly, if the user equipment is close to the cell center, more user equipment numbers or streams are allowed to be paired; and when the user equipment approaches the cell edge , then fewer user devices or streams are allowed to be paired.

According to an embodiment of the invention, the appropriate user equipment is first searched for pairing in the usual pairing strategy. A path loss characterizing the interference is then derived based on the wireless location of the user equipment, and the interference dependent threshold is calculated using the characterized interference to determine if the user equipment/stream can be paired. The interference dependent threshold is also calculated from equation (1). At the time of pairing, the increased capacity (uti ty) of the user equipment/stream, also known as the utility function, such as proportional fairness, is compared and compared to the combined capacity threshold, and the pairing is only performed below the threshold. The user device. This ensures that the total interference of all user equipments that can be assigned to the user equipment is below the set interference threshold.

In an embodiment of the present invention, the interference weighted multi-user-multiple-input multiple-output matrices may be used in combination, and the number of user equipments matched in the multi-user-multiple-input and multi-output is controlled by using the interference, so that the paired The total interference of the user equipment is below an interference threshold. For example, after selecting the user equipment with the largest weighted increased service capacity (proportional fairness), it may be further determined whether the increased proportional fairness of the paired user equipment is within the interference dependency threshold, and if it is met, the pairing may be performed, otherwise the pair.

Embodiments of the present invention also provide a multi-user-multiple-input multiple-out pairing device, such as a base station, which can perform the multi-user-multiple-input multiple-out method described above. 4 is a schematic structural diagram of a multi-user-multiple-input multiple-output pairing apparatus according to an embodiment of the present invention. Specifically, the multi-user-multiple-input multiple-pairing device 40 includes: a receiving device 42 configured to receive a wireless location of the user equipment in the wireless network; and an interference characterization device 44 configured to be characterized by the wireless location of the user equipment Interference; and pairing device 46, configured to use the interference weighted multi-user-multiple-input multiple-out matrix, and/or The interference is used to control the number of user devices paired in the multi-user-multiple-input and multi-input, so that the combined capacity of the paired user equipment is lower than an interference-related combined capacity threshold.

It should be pointed out that due to the development of technology and the updating of standards, components with the same function often have multiple different names. The technical terms used in the patent application of the present invention are for explaining and demonstrating the technical solutions of the present invention, and should be based on the functions that are recognized in the art, and cannot be arbitrarily interpreted only by the similarities and differences of the names. The technical content and technical features of the invention have been disclosed above, and it will be apparent to those skilled in the art that the invention may be substituted and modified without departing from the spirit and scope of the invention. Therefore, the scope of the present invention is not to be construed as being limited to the details of the embodiments disclosed herein.

Claims

1, a multi-user - multi-input and multi-out pairing method, including:

Receiving a wireless location of the user equipment in the wireless network;

Characterizing interference with the wireless location of the user equipment; and

Using the interference weighted multi-user-multiple-input and multi-output pairing matrix, and/or using the interference to control the number of user equipments paired in the multi-user-multiple-input and multi-output, so that the combined capacity of the paired user equipment is lower than an interference correlation The combined capacity threshold.

2. The multi-user-multiple-input and multi-out pairing method according to claim 1, wherein the interference characterized by the radio location of the user equipment is a path loss of a cell where the user equipment is located, and a path loss of the cell where the user equipment is located. The difference in path loss of neighboring cells, or the equivalent path loss of multiple coordinated cells in multipoint cooperation.

3. The multi-user-multiple-input multiple-out pairing method according to claim 1, wherein a weighting value of the multi-user-multiple-input-multiple-out pairing matrix is used, and the multi-user-multiple The interference-dependent threshold of the number of user devices paired in multiple is obtained by using the linear function β (ρι^) of the path loss.

0, PL, <= PL ₀

Ρτ _ ΡΤ

' ° ) * α, PL. < PL,

PL, - PL/. '

a PL, < PL. where O a ^ l , α is used to balance capacity and interference contribution, PLi is the path loss of the link between the user equipment and its serving base station i, PL _Q is the lower threshold of the path loss, ΡΙ ^ Is the upper threshold of the path loss.

4. The multi-user-multiple-input multiple-out pairing method according to claim 1, wherein when the interference weighted multi-user-multiple-input multiple-output matrices are used, further included in a serving cell/cluster, the serving base station measures from Serving all channel state information of the user equipment; calculating the sum of the paired additional user equipment or the increased service capacity using a typical multi-user-multiple-input and multi-out pairing strategy; and selecting the user equipment with the increased weighted maximum capacity by weighting until Achieve maximum sum capacity or maximum flow. The multi-user-multiple-input multi-output pairing method according to claim 1, wherein the multi-purpose is controlled using the interference When the number of user devices paired in multiple-input and multi-input, further includes finding the appropriate user equipment for pairing in the usual pairing policy; then using the interference to calculate the interference dependency threshold, determining whether the appropriate user equipment/flow is available Being paired.

6. The multi-user-multiple-input multiple-out pairing method of claim 5, further comprising calculating a proportional fairness of the user equipment/flow and comparing it to the interference dependent threshold.

7. A multi-user-multiple-input multi-output device, comprising:

a receiving device configured to receive a wireless location of the user equipment in the wireless network;

Interference characterization, configured to characterize interference with the wireless location of the user equipment; and

a pairing device configured to use the interference weighted multi-user-multiple-input-multiple-out matrices, and/or to use the interference to control the number of user devices paired in the multi-user-multiple-input and multi-out, so that the total number of paired user equipments The capacity is below a disturbance-related combined capacity threshold.

The multi-user-multiple-input and multi-output pairing device according to claim 7, wherein the interference characterized by the wireless location of the user equipment is a path loss of a cell where the user equipment is located, and a path loss of the cell where the user equipment is located. The difference in path loss of the phase cells, or the equivalent path loss of multiple coordinated cells in multi-point cooperation.

9. The multi-user-multiple-input multiple-out pairing device according to claim 7, wherein the weighting value of the interference weighted multi-user-multiple-input-multiple-out pairing matrix is used, and the multi-user-multiple-input is controlled using the interference The interference-dependent threshold of the number of user devices paired in the output is a linear function β (ρ is obtained using path loss,

0, PL, <= PL o

T ― Τ

( ' ° ) * , PL ₀ < PL, <= PL.

PL "PL. ' . ' i

a, PL, < PL, where 0 ≤ α ≤ 1, a is used to balance capacity and interference contribution, PLi is the path loss of the link between the user equipment and its serving base station i, PLo is the lower threshold of the path loss, PL Is the upper threshold of the path loss.

10. The multi-user-multiple-input multiple-out pairing device of claim 7, configured to further serve a serving cell/cluster when the interference weighted multi-user-multiple-input multiple-output matrices are used Measurement from its service All channel state information for the user equipment; use a typical multi-user-multiple-input multiple-out pairing strategy to calculate the sum of the paired additional user equipment or the increased service capacity; and choose to have weighted by (1-;5 (P£, )) Maximum weighted increased capacity of the user equipment until the maximum aggregate capacity or maximum flow is reached.

1 1. The multi-user-multiple-input multi-output pairing device of claim 7, configured to further control a number of user devices paired in the multi-user-multiple-input and multi-out using the interference The pairing strategy finds the appropriate user equipment for pairing; then uses the interference to calculate the interference dependency threshold to determine if the appropriate user equipment/flow can be paired.

12. The multi-user-multiple-input multiple-out pairing device of claim 11 configured to further calculate an increased proportionality of the user equipment/flow and compare it to the interference dependent threshold.