PDCCH constraint distribution tool algorithm and working method thereof

Abstract

The invention relates to the technical field of wireless communication, and discloses a PDCCH (Physical Downlink Control Channel) constraint allocation tool algorithm and a working method thereof. The PDCCH constraint allocation tool algorithm comprises the steps of PDCCH allocation collision cause analysis in a same-frequency interference scene, PUCCH resource expansion cause analysis, tool initial import interface, CCE initial value calculation in an RNTI value range, CCE search selection and reallocation based on a multiplexing layer, PDCCH initial CCE position control to determine PUCCH resources which are gradually increased in sequence. And importing a processing method of a baseband board scheduling module. The method is reasonable in design, a PDCCH allocation constraint mechanism is provided and a tool algorithm is designed from an extension root cause-CCE allocation rule which causes the PDCCH collision probability and the number of RBs of the PUCCH so that control channel resources can be utilized more efficiently, and the PDCCH constraint allocation tool algorithm design can utilize the control channel resources more efficiently based on the PDCCH allocation constraint mechanism.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and in particular to a PDCCH constraint allocation tool algorithm and a working method thereof. Background Art

[0002] The transmission of wireless communication system mainly includes control message and service data. As the index of service data transmission, the correct demodulation of control message is a prerequisite for user access, switching and high-speed service. The misdetection of control message will inevitably lead to the meaninglessness of service data transmission. All downlink physical layer / application layer control information in LTE is transmitted in the radio frame control area. Among them, PCFICH is used to inform the UE of the size of the control area. It uses position offset, scrambling code, repetition coding and other technologies, which is less affected by the wireless environment and has high reception reliability. PHICH carries 1 bit of ACK / NACK response information of PUSCH channel, and performs orthogonal multiplexing based on random sequence. It has little impact on network performance for hybrid HARQ single transmission feedback. PDCCH transmission scheduling and other control information include transmission format, resource allocation, uplink scheduling permission, power control and uplink retransmission and other main control information of all service transmission. Whether it is received correctly is the main determinant of the normal operation of the system.

[0003] PDCCH resource allocation is based on CCE. Due to its capacity limitation, resource allocation needs to compromise between the number of users and system efficiency. In the early stage, 3GPP used the Harsh formula in Samsung's proposal to determine its resource allocation method to improve the reliability of its PDCCH transmission, so as to increase the randomness of the control resource arrangement and reduce its collision probability. However, due to the growing demand for mobile communication technology in recent years, the increasing shortage of spectrum resources has become increasingly apparent. By introducing co-frequency networking technologies such as RRU co-cell to improve spectrum efficiency, at the same time, with the emergence of large-scale commercial networks, co-frequency interference problems frequently occur. The early standard formulation was formulated under the premise that co-frequency interference was not serious. The Harsh formula can effectively improve the reliability of PDCCH allocation at this stage. In the scenario of severe co-frequency interference, it will cause PDCCH collision and PUCCH resource expansion, which will directly lead to a sharp deterioration of network performance. This is also the main problem encountered by Japan SoftBank in the current scenario. Later, 3GPP also considered the elimination of PDCCH interference through the introduction of Hetnet (heterogeneous network), but it has a large change in the original networking structure and is not suitable for the commercial network that has been built. Therefore, the present invention mainly starts from the extended root cause of the PDCCH collision probability and the number of RBs of PUCCH - the CCE allocation law, proposes a PDCCH allocation constraint mechanism and designs a tool algorithm to more efficiently utilize control channel resources; therefore, we propose a PDCCH constraint allocation tool algorithm and its working method to solve this problem. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings mentioned in the above background technology and to propose a PDCCH constraint allocation tool algorithm and a working method thereof.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A PDCCH constraint allocation tool algorithm includes: PDCCH allocation collision cause analysis in a co-channel interference scenario, PUCCH resource expansion cause analysis, tool initial import interface, CCE start value calculation within the RNTI value range, CCE search selection and reallocation based on the multiplexing layer, control of PDCCH start CCE position to determine the PUCCH resources that increase in sequence, and a processing method for importing a baseband board scheduling module.

[0007] Preferably, it also includes: frame-based CCE allocation, that is, limiting a certain RNTI to be scheduled only in certain subframes, increasing CCE based on frequency reuse, and controlling dynamic A / N code channel numbers on this basis, so as to avoid collisions, improve the probability of successful control information detection, and increase service data rate in the same-frequency interference scenario;

[0008] Limiting a certain RNTI to be scheduled only in certain subframes is to search the RNTI and the subframe number in ascending order to find the minimum PDCCH start CCE position. The search result results in limiting the RNTIs that can be used in different subframes.

[0009] The present invention also discloses a working method of a PDCCH constraint allocation tool, comprising the following steps:

[0010] S1: Number the network multiplexing layer N according to the base station engineering parameter table;

[0011] S2: Import the base station engineering parameter table and network multiplexing layer number table, select the calculation content, and set the number of adjacent multiplexing layers;

[0012] S3: Perform secondary number allocation;

[0013] S4: Calculate the CCE starting value within the RNTI value range;

[0014] S5: Select a suitable CCE start value through search and record its RNTI and k value;

[0015] S6: the value of is incremented once, the value of c remains unchanged (within the allowed range of the value of c), and the PUCCH resources that are incremented in sequence are determined;

[0016] S7: When the Calculate CCE Start & PUCCH checkbox is selected, the PUCCH start position is calculated;

[0017] S8: the mU value is increased once, the c value remains unchanged once, and the corresponding result calculation table is output;

[0018] S9: Import the CCE start position excel table output by the tool into the LMT interface in the form of a parameter table for use by the scheduling algorithm;

[0019] S10: In the scheduling algorithm, for services with lower latency priority, the corresponding CCE starting position is modified, and for services with higher latency priority, no change is made

[0020] Preferably, the steps S9 and S10 are not implemented by the tool for controlling PDCCH allocation, but need to be implemented on the baseband board in conjunction with the base station development debug port.

[0021] Preferably, in S1, the multiplexing layer in the network multiplexing layer number N refers to cells using the same frequency, and these cells form a multiplexing cluster, also called a multiplexing layer. In order to control the impact of co-channel interference, these cells are numbered by cluster, and the number value N increases from 1 upwards, and the cell cluster numbers used in the cluster are consistent. Cells with consistent cluster numbers do not consider the PDCCH collision problem;

[0022] Preferably, in S5, the k value represents a subframe number, which is counted from the initial operation of the system.

[0023] Preferably, in S6 and S8, the value is incremented once: it means that the available values ​​defined by 3GPP are incremented upward to select a value.

[0024] Preferably, in S8, the mU value is a sequence number value of a control PUCCH starting position that can be used in different subframes defined by 3GPP.

[0025] Compared with the prior art, the present invention mainly starts from the extended root cause of the PDCCH collision probability and the number of RBs of PUCCH - the CCE allocation law, proposes a PDCCH allocation constraint mechanism and designs a tool algorithm to more efficiently utilize control channel resources. The PDCCH constraint allocation tool algorithm design, based on the PDCCH allocation constraint mechanism, can more efficiently utilize control channel resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is an example diagram of multiplexing cell numbering of the present invention;

[0027] Figure 2 This is the initial interface diagram of the tool of the present invention. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0029] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0030] Reference Figure 1-2 , a PDCCH constraint allocation tool algorithm, including: PDCCH allocation collision cause analysis in the same-frequency interference scenario, PUCCH resource expansion cause analysis, tool initial import interface, CCE start value calculation within the RNTI value range, CCE search selection and reallocation based on the multiplexing layer, control of PDCCH start CCE position to determine the PUCCH resources that increase in sequence, and import processing method of baseband board scheduling module.

[0031] In this embodiment, it also includes: frame-based CCE allocation, that is, limiting a certain RNTI to be scheduled only in certain subframes, increasing CCE based on frequency reuse, and controlling dynamic A / N code channel numbers on this basis, so as to avoid collisions, improve the probability of successful control information detection, and increase service data rate in the same-frequency interference scenario;

[0032] Limiting a certain RNTI to be scheduled only in certain subframes is to search the RNTI and the subframe number in ascending order to find the minimum PDCCH start CCE position. The search result results in limiting the RNTIs that can be used in different subframes.

[0033] The present invention also discloses a working method of a PDCCH constraint allocation tool, comprising the following steps:

[0034] S1: Number the network multiplexing layer N according to the base station engineering parameter table;

[0035] S2: Import the base station engineering parameter table and network multiplexing layer number table, select the calculation content, and set the number of adjacent multiplexing layers;

[0036] S3: Perform secondary number allocation;

[0037] S4: Calculate the CCE starting value within the RNTI value range;

[0038] S5: Select a suitable CCE start value through search and record its RNTI and k value;

[0039] S6: the value of is incremented once, the value of c remains unchanged (within the allowed range of the value of c), and the PUCCH resources that are incremented in sequence are determined;

[0040] S7: When the Calculate CCE Start & PUCCH checkbox is selected, the PUCCH start position is calculated;

[0041] S8: the mU value is increased once, the c value remains unchanged once, and the corresponding result calculation table is output;

[0042] S9: Import the CCE start position excel table output by the tool into the LMT interface in the form of a parameter table for use by the scheduling algorithm;

[0043] S10: In the scheduling algorithm, for services with lower latency priority, the corresponding CCE starting position is modified, and for services with higher latency priority, no change is made

[0044] In this embodiment, steps S9 and S10 are not implemented by the tool for controlling PDCCH allocation, but need to be implemented on the baseband board in conjunction with the base station development debug port.

[0045] In this embodiment, in S1, the multiplexing layer in the network multiplexing layer number N refers to cells using the same frequency. These cells form a multiplexing cluster, also called a multiplexing layer. In order to control the impact of co-channel interference, these cells are numbered by cluster, and the number value N increases from 1 upwards. The cell cluster numbers used in the cluster are consistent. Cells with consistent cluster numbers do not consider the PDCCH collision problem;

[0046] In this embodiment, in S5, the k value represents the subframe number, which is counted from the initial operation of the system.

[0047] In this embodiment, in S6 and S8, the value is incremented once: it means that the available values ​​defined by 3GPP are incremented upward to select a value.

[0048] In this embodiment, in S8, the mU value is a sequence number value of the starting position of the control PUCCH that can be used in different subframes defined by 3GPP.

[0049] In this embodiment, based on the PDCCH allocation constraint mechanism, control channel resources can be used more efficiently. Figure 1 and Figure 2 ;

[0050] The PDCCH time domain is located in the first few OFDM symbols of the downlink subframe, while the frequency domain is distributed over the entire downlink bandwidth, and its capacity is limited by time and frequency resources. According to the 3GPP protocol, the starting CCE of PDCCH is determined by C-RNTI (Radio Network Temporary Identifier) ​​and the subframe number. At the same time, its starting position will affect the allocation of dynamic PUCCH resources and the success rate of uplink ACK / NACK detection. Therefore, by controlling the sequential allocation of PDCCH, it is allocated as much as possible at the front end of the control area to reduce the collision probability of PDCCH and maximize the compression of the number of PUCCH RBs. This is an effective means to improve network performance in multi-user scenarios;

[0051] 1. Calculation of available PDCCH resources

[0052] The TD-LTE control area consists of four parts: PCFICH, PHICH, PDCCH and reference signal. When mapping resources, the eNodeB first maps the reference signal, then PCFICH and PHICH, and finally PDCCH resources. The mapping positions of the first three parts are related to the cell configuration and are scattered on different symbols and carriers. Therefore, when mapping PDCCH resources, the remaining REs are first reformatted - REG and CCE resource division is performed, and finally allocated to PDCCH. The number of CCEs available for PDCCH is:

[0053]

[0054] N REG It is obtained by calculating the total number of REGs in the control area - the number of REGs occupied by the reference signal - the number of REGs occupied by the PCFICH (fixed to be 4) - the number of REGs occupied by the PHICH (not necessarily existing, depending on the base station parameter configuration).

[0055]

[0056] Where CFI∈{1,2,3} represents the size of the control region, i.e., 1 or 2 or 3 OFDM symbols, which is notified to the UE by PCFICH); N is the number of RBs under different system bandwidths. LTE supports 1.4M, 3M, 5M, 10M, 15M, and 20M bandwidths. Table 1 below shows the number of RBs corresponding to various LTE bandwidths specified by the 3GPP protocol; g ∈{1,2,3}, its value is determined by the number of PHICH processes contained in an RB, and the specific value is determined by the upper layer.

[0057] Table 1 RB configurations for different bandwidths in 3GPP protocols

[0058]

[0059] 2. Analysis of factors affecting the starting CCE number of PDCCH

[0060] The terminal monitors the PDCCH candidate set in non-idle mode. This set is the terminal search space, which is divided into a common search space and a UE-specific search space. The common search space is used to transmit messages such as paging, random response, and broadcast, and the spatial position starts from CCE0; the UE-specific search space is used to transmit control information related to uplink and downlink shared channels, and its starting position can be calculated by the HASH function. By analyzing the inherent relationship between the CCE start number of the space and the C-RNTI and subframe number, the allocation rule can be mastered. The spatial position of the CCE corresponding to PDCCH candidate m is:

[0061]

[0062] Where N CCE,k is the total number of CCEs in the control region of the kth subframe, i.e., 1 in N CCE ; L is the aggregation level, and L∈{1,2,4,8}, i=0,...,L-1; Y k and m′ distinguish the values ​​of the common search space and the UE-specific search space. For the common search space, m′=m, Y k =0, L∈{4,8}, for UE-specific search space:

[0063] ① If the UE is configured with CIF (Carrier Identification Field Value), m′=m+M (L) ×n CI , where n CI That is, the CIF indication value; ② If the UE is not configured with CIF, m′=m(m=0,…,M (L) -1),M (L) is the number of PDCCH candidates in the search space, corresponding to different DCI formats, and its specific values ​​are shown in Table 2; ③Y k =(A×Y k-1 )modD,Y -1 =n RNTI ≠0,A=39827,B=65537, n RNTI Temporary identification value of wireless network, n S The timeslot number in a subframe.

[0064] Table 2 PDCCH candidate (terminal monitoring) table

[0065]

[0066] It can be deduced that the starting position of CCE is not only related to RNTI, but also to the subframe number. At the same time, due to the modulo operation, it is easy to disrupt the incremental nature of the allocated CCE numbers.

[0067] 3. Analysis of the impact of CCE start number on PUCCH resource expansion and compression

[0068] The PDCCH start CCE affects the allocation of dynamic PUSCH resources, and its dynamic A / N code channel number is related to the start CCE position. Within the HARQ reception window, the UE receives all PDCCHs indicated by PDCCH (including dynamic scheduling and SPS activation) or PDCCHs indicating SPS release, and calculates the PUCCH resources used on different antenna ports:

[0069] The UE will select a c value that belongs to {0,1,2,3} so that Nc≤n CCE ≤N C+1 ,in is the number of subcarriers on a single RB;

[0070] For two antenna ports (p∈[p0, p1]), the PUCCH resources used are calculated using the following formulas:

[0071]

[0072] Cell-level parameters configured by high-level CCE is the first CCE number of the downlink DCI last received by the UE in the HARO receiving window; M is the number of ACK / NACK replies in the same uplink subframe for PDSCHs sent in multiple downlink subframes; m U is the sequence number value corresponding to the subframe. Among the ratios 0, 1, 2, and 5, ratio 5 does not support format1b, and ratio 2 corresponds to the largest M=4. From the above formula, the dynamically allocated code channel number increases with the CCE sequence number, but because it is affected by both the c value and the m value, there must be jumps in the increasing process.

[0073] Development of PDCCHCCE Allocation Constraint Tool The starting position of CCE does not increase according to RNTI, but changes in different downlink subframes, which causes the maximum number of PUCCH dynamic allocation to be out of order. Therefore, it is not feasible to control CCE sorting and PUCCH resource compression by sequential allocation of RNTI. Therefore, frame-based CCE allocation is proposed, that is, limiting a certain RNTI to be scheduled only in certain subframes for control. Based on the characteristics of large data processing volume, flexible calculation, and simple interface of Excel, VBA programming language is used to develop CCE constraint allocation tool based on Datang Mobile's actual communication equipment parameters (Table 3) and RNTI value range (Table 4):

[0074] Table 3 PDCCH tool development parameters

[0075]

[0076] Table 4 RNTI value range

[0077]

[0078]

[0079] (1) The network multiplexing layer is numbered N according to the base station engineering parameter table (using longitude, latitude, station spacing, and frequency). The base stations in the same multiplexing layer have the same N value and are recorded in the form of (cell name, multiplexing layer number) in an Excel table (network multiplexing layer label table). This needs to be done manually. Any commercial network only needs to assign values ​​once after the network is built.

[0080] (2) According to Figure 2 The initial interface of the tool shown in the figure imports the base station engineering parameter table and the network multiplexing layer number table obtained in (1), selects the calculation content, and sets the number of adjacent multiplexing layers m. REU , the default value is 1 (the central reuse cell is generally surrounded by 6 adjacent reuse cells, but LTE is mostly co-frequency networking, so it is set to 1);

[0081] (3) Extract n from the process parameter table CI Equal value, and perform secondary number assignment X, X = N mod M reu ;

[0082] (4) Calculate N in the range of 0001-FFF3 (reserved and not involved in allocation, M-RNTI, P-RNTI, and SI-RNTI are less affected in actual tests and are not considered) in Table 4 using formulas (1), (2), and (3). CCE 、N REG , and the CCE starting position, and the CCE position calculation results are named and stored in a separate Excel table. Some calculation results (aggregation level is 4) are shown in Table 5, where k=2, 7 are uplink subframes and do not need to be considered.

[0083] Table 5 CCE start position table

[0084]

[0085]

[0086] (5) Allocation starts. The result of (1) is used to search for CCEs from small to large according to RNTI and then k value, and the minimum CCE position value CCE is obtained. min, start searching again from the RNTI and k value of 0, increase by L, find X1 CCEs that meet the condition (X1 value is the number of users in the multiplexing layer, corresponding to the traffic statistics of each cell, or the number of users in the engineering parameter table), stop searching, and record the RNTI and k value of the cell in a table, as shown in Table 6.

[0087] Table 6 Sorting index table

[0088]

[0089]

[0090] (6) Continue to allocate the remaining X-1 cells and search for cells with a value greater than CCE starting from RNTI and k=0. min +X1L, and the search stops after the CCE that meets the increment condition is found, and the RNTI and k value of the cell are also recorded in a table. After completion, the same search process is used for other reused cells, and the search is greater than And the increasing condition CCE is satisfied.

[0091] (7) When the Calculate CCE Start & PUCCH checkbox is selected, the PUCCH start position is calculated according to (4) and (5), and the results are stored in Excel (part of the calculation results are shown in Table 7);

[0092] Table 7 PUCCH Value table

[0093]

[0094] (8) Table 7 Calculation results According to the CCE number, it is divided into 3 segments: 0-21, 22-54, 55-87, where mU = 0, 1, 2, n CCE The value range satisfies 0≤n CCE <88, mU=3 corresponds to a special subframe, which occupies at most 2 OFDM symbols. CCE The value range satisfies 0≤n CCE <55 The lower the segment, the smaller the dynamically allocated number is. It increases by 1 in the segment. At the same time, it is affected by the c value and the mU value. There are jumps in the increase, but the increase is continuous between segments. For example, mU=0, c=1 and mU=1, c=1. Therefore, when the c value in formulas (4) and (5) is satisfied, the mU value is increased once and the c value remains unchanged once, and the corresponding result calculation table is output.

[0095] (9) Import the CCE starting position Excel table output by the tool into the LMT interface in the form of a parameter table for use by the scheduling algorithm.

[0096] (10) In the scheduling algorithm, for services with lower latency priority, the corresponding CCE starting position is modified, while for services with higher latency priority, no change is made.

[0097] Although the present invention has been described above with reference to the embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the various features in the embodiments disclosed in the present invention may be used in combination with each other in any manner, and the fact that these combinations are not exhaustively described in this specification is only for the sake of omitting space and saving resources. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0098] The standard parts used in the present invention can all be purchased from the market, and special-shaped parts can be customized according to the instructions and the drawings. The specific connection methods of each part adopt conventional means such as mature bolts, rivets, welding, etc. in the prior art. Machinery, parts and equipment all adopt conventional models in the prior art, and the circuit connection adopts the conventional connection method in the prior art, which will not be described in detail here.

Claims

1. A PDCCH constraint allocation tool algorithm, characterized in that: include: Analysis of the causes of PDCCH allocation collisions in co-channel interference scenarios, analysis of the causes of PUCCH resource expansion, initial import interface of the tool, calculation of the CCE starting value within the RNTI value range, search, selection and reallocation of CCE based on the multiplexing layer, control of the PDCCH starting CCE position to determine the PUCCH resources that increase in sequence, and processing methods for importing the baseband board scheduling module.

2. The PDCCH constraint allocation tool algorithm according to claim 1, characterized in that: Also includes: Frame-based CCE allocation, i.e. limiting a certain RNTI to be scheduled only in certain subframes, increasing CCE based on frequency reuse, and controlling dynamic A / N code channel numbers on this basis, in order to avoid collisions, improve the probability of successful control information detection, and increase service data rates in co-channel interference scenarios; Limiting a certain RNTI to be scheduled only in certain subframes is to search the RNTI and the subframe number in ascending order to find the minimum PDCCH start CCE position. The search result results in limiting the RNTIs that can be used in different subframes.

3. A working method of a PDCCH constraint allocation tool, characterized in that: The following steps are involved: S1: Number the network multiplexing layer N according to the base station engineering parameter table; S2: Import the base station engineering parameter table and network multiplexing layer number table, select the calculation content, and set the number of adjacent multiplexing layers; S3: Perform secondary number allocation; S4: Calculate the CCE starting value within the RNTI value range; S5: Select a suitable CCE start value through search and record its RNTI and k value; S6: the value of is incremented once, the value of c remains unchanged (within the allowed range of the value of c), and the PUCCH resources that are incremented in sequence are determined; S7: When the Calculate CCE Start & PUCCH checkbox is selected, the PUCCH start position is calculated; S8: the mU value is increased once, the c value remains unchanged once, and the corresponding result calculation table is output; S9: Import the CCE start position excel table output by the tool into the LMT interface in the form of a parameter table for use by the scheduling algorithm; S10: In the scheduling algorithm, for services with lower delay priority, the corresponding CCE starting position is modified, and for services with higher delay priority, no change is made.

4. The working method of the PDCCH constraint allocation tool according to claim 3, characterized in that: The steps S9 and S10 are not implemented by the tool for controlling PDCCH allocation, but need to be implemented on the baseband board in combination with the base station development and debugging port.

5. The working method of the PDCCH constraint allocation tool according to claim 3, characterized in that: In S1, the multiplexing layer in the network multiplexing layer number N refers to cells using the same frequency, and these cells form a multiplexing cluster, also called a multiplexing layer. In order to control the impact of co-frequency interference, these cells are numbered by cluster, and the number value N increases from 1 upwards, and the cell cluster number used in the cluster is consistent. The PDCCH collision problem is not considered for cells with the same cluster number.

6. The working method of the PDCCH constraint allocation tool according to claim 3, characterized in that: In S5, the k value represents the subframe number, which is counted from the initial operation of the system.

7. The working method of the PDCCH constraint allocation tool according to claim 3, characterized in that: In S6 and S8, the value is incremented once: it means that the available values ​​defined by 3GPP are incremented upward to select a value.

8. The working method of the PDCCH constraint allocation tool according to claim 3, characterized in that: In S8, the mU value is a sequence number value of the control PUCCH starting position that can be used in different subframes defined by 3GPP.

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