Wireless network simulation method

Technical field of wireless network simulation simulation method

[0001] The present invention relates to a code division multiple access (Code Division Multiple Access, CDMA) cellular mobile communication system, and particularly relates to a wireless network simulation method (Evolution Data Optimized, EVDO) in a CDMA system. The principle can also be applied to wideband codes. Simulation of High-Speed Downlink Packet Access (HSDPA) wireless network in Wideband CDMA, WCDMA.

Background technique

[0002] Wireless network simulation is an important part of the entire wireless network construction process, and runs through the entire network construction from beginning to end. In the planning stage, network simulation can simulate the network coverage and capacity after the implementation of the plan in the design period before the network is implemented, and find possible problems in time based on the simulation results, and adjust the plan; in the optimization stage, pass Network simulation can verify the feasibility of optimization measures such as adding new sites and changing site information, so as to estimate the effects of adjustments in advance before the implementation of the optimization plan. It can be seen that network simulation greatly saves the time and manpower and material costs of wireless network construction and operation, and is an important foundation for ensuring high-speed and high-quality network construction.

[0003] The core of the wireless network simulation is the simulation algorithm, which is used to simulate the dynamic situation of the actual network, so as to calculate the performance indicators of the coverage during the actual network operation.

[0004] At present, the target of wireless network simulation is mainly CDMA IS95 or IX network. The air interface of these networks adopts power control technology in the front/reverse direction. For the downlink, the simulation target resource mainly considers that the downlink transmission power is different. The allocation between different terminals of the channel; for the uplink, the main consideration is the rise of power noise.

[0005] Aiming at these technical characteristics of the air interface, the common wireless network simulation method currently used is mainly the Monte Carlo iterative algorithm, which is based on the downlink power and the uplink noise floor threshold as the judgment conditions for convergence, and the system design The main goal is to be able to access as many users as possible at the same time. Therefore, the wireless network simulation aims at this goal by calculating the network performance under a certain number of users and distribution, so as to verify whether the network design meets the requirements.

[0006] Currently, the industry usually adopts a snapshot method. The method is to distribute the terminals in each snapshot according to a certain traffic distribution algorithm. The positions of these terminals will remain unchanged in each snapshot, and it is assumed that the terminals that can access will continue to occupy system resources. Snapshot the network performance, then average the results of multiple snapshots, and use the averaged result as the result of the entire network. When the number of snapshot objects is large enough, the averaged result has statistical significance close to the actual situation. For CDMAIS95 or IX networks, this simulation method is relatively mature and the accuracy is acceptable.

[0007] With the increasing requirements for spectrum efficiency, the increasing requirements for speed, and the asymmetry of uplink/downlink speed requirements, the original air interface technology can no longer meet the needs of users. Moreover, various 3G networks are currently trying to adopt new technologies to meet the increased demand. Among these new technologies, the most important thing is to no longer use power control technology in the downlink, but to use rate control technology. The essence of rate control is the automatic modulation and coding (AMC) technology, combined with the physical layer automatic repeat request (HARQ) technology. ) Technology and MAC layer scheduling technology, etc., make the control of resources more effective, the multi-user gain is obvious, and the downlink rate is relatively greatly improved.

[0008] The EVDO and HSDPA protocols are the integration and embodiment of these technologies, which are more and more adopted in actual commercial networks, and are the way to upgrade the original CDMA system. The new network also needs wireless network simulation, the original Monte Carlo

The Luo simulation algorithm does not incorporate new emerging technologies, especially the new technologies introduced to the downlink, and does not support the processing of service quality (QoS, Quality of Service) requirements. Therefore, such simulation algorithms cannot reflect the system well. Performance and status of actual work.

[0009] The following will briefly describe the schematic diagram of CDMA2000-1X EVDO forward channel time division multiplexing and user scheduling, as shown in Figure 1:

[0010] The forward channel is used as a "wide channel" for time sharing by all users. The smallest unit of time division is a time slot, a time slot may be allocated to a user to transmit data or allocated to overhead message transmission (called active slot), or it may be in an idle state without sending any data (called For idle slot).

[0011] Due to the time division multiplexing of the forward traffic channel, which user to send data to at a certain moment is determined by the forward channel scheduler according to a certain scheduling strategy, and different schedulers will affect users in different wireless environments. The throughput has a strong impact.

[0012] The goal of scheduling is to make all users in the same cell as fair as possible and maximize the total throughput of the cell as much as possible. However, there is a contradiction between these two goals. For example, if the goal is to maximize the throughput of the entire cell, the scheduling strategy should be to send data to the terminal with the best wireless environment. This will inevitably lead to the result that users at the edge cannot basically be served.

[0013] Therefore, in order to solve the problem of inequity, the final scheduling algorithm will be a compromise between these two goals. At present, the Proportional fair scheduler usually adopted by the system is such an algorithm that balances efficiency and fairness. The main principle of the algorithm is to track the following two variables: the users current application rate DRC(k), and user history The throughput is T(k), and scheduling is performed according to the ratio DRC(k)/T(k). Therefore, it can be seen that the higher the user's current application rate, the more likely it is to get service; the higher the user's historical throughput, it means that it has received more service opportunities before, and the probability of getting service later is smaller.

[0014] As mentioned above, wireless network simulation plays a very important role in wireless network planning and optimization. If the technical characteristics of CDMA2000-1X EVD0 can be introduced and service QoS requirements can be introduced, a wireless network that adapts to the forward scheduling technology of base stations can be proposed. Network simulation method, so that the wireless network simulation algorithm can better adapt to the requirements of the new air interface technology, further improve the simulation accuracy, and make the wireless network simulation play a greater role in the planning and optimization of the new network (EVDO, HSDPA), which is undoubtedly ideal . Unfortunately, the technology related to this has not yet been implemented.

Summary of the invention

[0015] The present invention is made in consideration of the above-mentioned problems. To this end, the main purpose of the present invention is to provide a wireless network simulation method.

[0016] According to an embodiment of the present invention, a wireless network simulation method is provided.

[0017] The method includes the following processing: step S402, perform snapshot loop initialization; step S404, perform a reverse link rate assignment process and a forward processing process; step S406, calculate the average cell throughput based on the QoS requirements of the service supported by the terminal And the average rate; and step S408, in the case that the number of snapshot cycles does not reach the preset threshold, repeat steps S402 to S406.

[0018] In step S406, when the services supported by the terminal all have QoS requirements, the average throughput of the forward cell is calculated by the following formula: ThrougputFL, where P is the z=1 of the forward reverse access terminal Number, and 1 Vp Wm; if the service supported by the terminal does not have QoS requirements, use the following formula before calculating

Add to the average throughput of the cell, where 5 is the number of forward access terminals; in addition, when the service part supported by the terminal has QoS requirements, the average throughput of the forward cell is calculated by the following formula: Kahata%=inWhere, where is the forward and backward with QoS requirements nm μ <=i DRC, the number of access terminals, and 1 <p W m, nm is the number of forward access terminals without QoS requirements .

[0019] Here, the forward average rate can be calculated by the following formula: DataRate_FL = Throughput_FL/ NumMob orders e, where NumMobile is the number of forward access users. And, the reverse average rate can be calculated by the following formula: DataRate_EL = Throughput_EL/NumMob Order e, where NumMobile is the number of reverse access users, and Througput^ = R^j, Througput_ELIt is the average throughput of the reverse cell.

<=1

[0020] Specifically, in step S404, the reverse link rate assignment process includes:

[0021] Step S702, all terminals are sorted according to the reverse QoS priority, and the terminals with high QoS priority services are placed in front of the sequence, the terminals with low QoS priority services are placed behind, and the terminals without QoS requirements are randomly selected. Placed at the end of the sequence;

[0022] Step S704: Perform data rate initialization for each terminal according to the terminal's access sequence;

[0023] Step S706: Calculate the transmission power of the terminal service channel corresponding to the data rate, and calculate the total transmission power of the terminal;

[0024] Step S708: Determine whether the total transmit power of the terminal exceeds the maximum transmit power threshold of the terminal;

[0025] In the case where the judgment result is yes, proceed to step S712, otherwise, proceed to step S710, step S710, and judge whether the noise received by the relevant cell rises above the threshold due to the access of the i-th terminal. If the judgment result is yes, proceed to step S712, otherwise, it is recorded that the terminal access is successful;

[0026] And step S712, it is judged whether the data rate of the i-th terminal can be reduced, and if the judgment result is yes, the data rate is reduced by one level according to the rate level; otherwise, it is recorded as a terminal access failure.

[0027] Wherein, after the data rate is reduced by one level in step S712, it is determined whether the degraded data rate is lower than the minimum rate threshold. If the result of the determination is no, the processing returns to step S706, otherwise, it is recorded as a terminal Access failed.

[0028] In addition, in step S404, the forward processing flow includes:

[0029] Step S802: Determine the total number of cells within the simulation range and the initial cells;

[0030] Step S804, determine the terminal belonging to the initial cell;

[0031] Step S806, sort the terminals according to the forward service priority;

[0032] Step S808: Screen terminals that cannot meet the forward QoS requirements;

[0033] Step S810, determine whether there is a terminal that cannot meet the forward QoS requirement according to the screening result of step S808, and if the determination result is yes, proceed to step S812, otherwise, proceed to step S814;

[0034] Step S812, processing the terminal that cannot access the initial cell in the forward direction; and

[0035] Step S814, input the terminal sequence that can access the initial cell and the terminal that may be deleted.

[0036] Wherein, the sorting in step S806 may specifically be the following processing:

[0037] Step S902: Read the attributes of the terminals included in this snapshot one by one, and check whether the services supported by the terminal are optimal.

Advanced requirements

[0038] Step S904: For terminals without priority requirements, they are classified as a forward non-priority terminal set;

[0039] Step S906, for the QoS service terminals with priority requirements, belong to the forward priority terminal set; and

[0040] Step S908: After traversing all the terminals, sort the terminals in the forward priority terminal set according to priority and place them at the front of the terminal sequence, and randomly sort the terminals in the forward non-priority terminal set. And placed at the back end of the terminal sequence.

[0041] At this time, step S908 may specifically include the following processing:

[0042] Step S1002, sort the terminals of the cell according to the forward service priority;

[0043] Step S1004, set P=1, and determine the number of terminals with QoS requirements as M, where M is an integer greater than or equal to 0;

[0044] Step S1006, determine whether P is greater than M, and if P is greater than M, output the accessible terminal sequence and the inaccessible terminal sequence, and if P is less than or equal to M, proceed to step S1008;

[0045] Step S1008, the first P terminals with QoS requirements are judged according to the following formula, and subsequent processing is performed according to the judgment result:

[0046]

[0047] Formula 1:

Rfl-i

DRC] ⁺ DRC₂⁺ Eight cards _Q Rfl-i IR~FL-2 I Male ^^2：DRC1⁺DRC2 ⁺

[0048]

[0049] Eight_rx Rfl-i, RfL·2 I Equation 3: drg DRC₂

DRC_p

I RpL-P - Dg_

DRC_p Among them, in the case where the formula 1 holds, make P = p+1, and the process proceeds to step S1006; in the formula

When 2 is established, put all terminals after the Pth terminal into the inaccessible terminal set, and output the accessible terminal sequence and the inaccessible terminal sequence; in the case of formula 3, the first P terminals are put into the set of terminals that cannot be accessed, and P=P+1, and the process proceeds to step S1006.

[0050] In addition, between step S404 and step S406, if forward adjustment is required, a forward adjustment algorithm is executed, or if a reverse adjustment is required, a reverse adjustment algorithm is executed.

[0051] In addition, before step S402, the following processing is further included: calculating the forward DRC rate corresponding to the candidate set on each grid based on the comparison between the actual forward demodulation signal-to-noise ratio for/Ioc and the system demodulation threshold; where , According to the actual signal-to-noise ratio Ior/Ioc value on each grid to determine the forward DRC rate group that can be supported by different cells corresponding to the current grid, when the actual Ior/Ioc value is between the two data rates corresponding to the demodulation When between the thresholds, the lower rate is taken as the forward DRC rate that can be supported. By aiming at the technical characteristics of CDMA2000-1X EVD0 and introducing QoS requirements, the above technical solution of the present invention makes the wireless network simulation algorithm more adaptable to the requirements of the new air interface technology, further improves the simulation accuracy, and enables the wireless network simulation to be approximated to a great extent The network status of the new network (EVD0, HSDPA) system enables wireless network simulation to play a greater role in its planning and optimization, thereby guiding network planning and optimization more efficiently.

Description of the drawings

[0052] The drawings described here are used to provide a further understanding of the present invention, and constitute a part of this application.

CN 101653021 Β

The illustrated exemplary embodiments and their descriptions are used to explain the present invention, and do not constitute an improper limitation of the present invention. In the attached picture:

[0053] FIG. 1 is a schematic diagram of channel time division multiplexing according to related technologies;

[0054] FIG. 2 is an overall flowchart of the actual implementation of the wireless network simulation method according to an embodiment of the present invention;

[0055] FIG. 3 is a flowchart of determining a candidate set in the process of FIG. 2;

[0056] FIG. 4 is a flowchart of a wireless network simulation method according to an embodiment of the present invention;

[0057] FIG. 5 is a processing flowchart of the first solution of a wireless network simulation simulation method according to an embodiment of the present invention;

[0058] FIG. 6 is a processing flowchart of a second solution of a wireless network simulation method according to an embodiment of the present invention.

[0059] FIG. 7 is a reverse link rate assignment process in a wireless network simulation simulation method according to an embodiment of the present invention;

[0060] FIG. 8 is a flowchart of forward processing in a wireless network simulation method according to an embodiment of the present invention;

[0061] FIG. 9 is a processing flow chart of prioritizing forward services in the forward processing flow of FIG. 8; and [0062] FIG. 10 is a screening of terminals that cannot be accessed forward in the forward processing flow of FIG. 8 The process flow chart of the collection.

Detailed ways

[0063] The present invention fully considers the technical characteristics of AMC technology, physical layer hybrid HARQ technology hybrid, rate control, especially the scheduling mechanism of the base station, and also considers the simulation processing of hybrid services with and without QoS (Quality of Service) requirements. , Proposed a new network simulation method, which is simple and clear, and can accurately reflect the changes in air interface technology.

[0064] In general, in the present invention: firstly, according to the characteristics of CDMA2000-1X EVDO forward channel full power transmission, the forward basic coverage static analysis is completed in the first stage of the simulation process; secondly, in the simulation process In the iterative process, complete the reverse basic coverage iterative analysis; again, according to the current QoS requirements of the actual system, introduce the QoS demand discrimination and processing in the simulation method, and adjust the reverse rate according to the processing results; finally, pass For the processing of the scheduling algorithm, a new algorithm is introduced to complete the calculation of the forward average rate and cell throughput.

[0065] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0066] As shown in FIG. 2, based on the principles of CDMA2000-1X EVDO forward channel time division multiplexing and user scheduling, combined with network simulation algorithms, the processing for implementing the wireless network simulation simulation method of the present invention includes:

[0067] Step S201, input of geographic information and initialization of network configuration parameters:

[0068] In this step, the initialization of the wireless network simulation is performed, which mainly includes importing a three-dimensional electronic map, and assigning initial values to the network including base stations, terminals, carriers, and bearers. Among them, the three-dimensional electronic map includes at least elevation and additional Feature information and vector information such as roads and rivers.

[0069] Step S202: Calculate the path loss of each cell:

[0070] In this step, first, determine the range to be simulated; then, calculate the path loss of each cell on each grid within the specified range. The grid refers to a square with the minimum accuracy of the three-dimensional electronic map as its side length. The smallest unit that can be divided in a three-dimensional electronic map; the specified range is determined by setting a certain path loss threshold. When the path loss of a cell on a certain grid exceeds this threshold, it is considered that the distance between this grid and the cell is far enough and not needed Consider the impact of the cell. The value of the path loss threshold is variable and is affected by factors such as environment and network scale.

[0071] Step S203: Determine the candidate set and the strongest cell on each grid:

[0072] The determination of the candidate set is based on the pilot signal-to-noise ratio from the relevant cell to each grid, where the pilot signal-to-noise ratio is closely related to the path loss of each grid relative to each relevant cell. CDMA2000-1XEVD0 forward channel adopts full power transmission

That is, the power of the forward pilot channel is also the total forward transmission power. The pilot signal-to-noise ratio from the relevant cell to each grid can be calculated through the pilot transmission power and path loss. The set thresholds of candidate sets are compared to determine the candidate sets of coverage cells on each grid; then, the cells with the strongest pilot signal-to-noise ratio in each grid are recorded, and the strongest cell is recorded in each cell as the grid of the current cell. Grid information, this step is shown in Figure 3.

[0073] Step S204: Calculate the forward DRC rate corresponding to the candidate set on each grid:

[0074] Based on the coverage cell candidate set, calculate the CDMA2000-1X EVD0 forward DRC (Date Rate Control) rate that can be supported by each cell in the candidate set on each grid. The calculation of the DRC rate is based on the comparison between the actual forward demodulation signal-to-noise ratio ίθΤ/Ioc and the system demodulation threshold. Different system demodulation thresholds correspond to different DRC rates, and look up the table according to the actual signal-to-noise ratio Ior/Ioc value of each grid to determine the forward DRC rate group that can be supported by the current grid corresponding to different cells. When the actual value of ior/ioc is between the corresponding demodulation thresholds of the two data rates, the lower rate is taken as the forward DRC rate that can be supported.

[0075] Step S205, setting the terminal type and ratio:

[0076] In order to facilitate the setting of the traffic volume, in this step, the terminal type is set according to the principle of one-to-one correspondence between the terminal type and the carried service, and the terminal ratio is set according to the load of the service in the simulation target.

[0077] Step S206, network simulation process;

[0078] Step S207, output the simulation diagram and statistical results, and the network simulation ends; and

[0079] Finally, the processing ends.

[0080] FIG. 3 is a flowchart of the processing of determining the candidate set in step S203 described above, and the specific steps are as follows:

[0081] Step S301: Calculate the pilot power Ppsetoti from each cell on the current grid by using the following formula:

[0082] Ppiloti=P_tXj ^Pathloss;,

[0083] Among them, i = 1 to M, Pt "is the total transmit power of the i-th cell; PathlosSi is the path loss from the i-th cell to the current grid; M represents the number of cells related to the current grid. For In the actual network, due to the fact that some cells are far away from a certain grid, the correlation is small and can be excluded. The processing method is to set a certain path loss threshold, when the path loss of a certain cell to the grid exceeds this At the time of the threshold, it is considered that the cell is not related to the grid, and the size of M is determined by this. The path loss threshold is consistent with the threshold in step S202.

[0084] Step S302: Calculate the total received power Ioj on the grid using the following formula:

Μ

[0085] Ioj=Work PJ Pathlossi where j is a grid mark.

i=l,

[0086] Step S303: Calculate the pilot signal-to-noise ratio Eci/Ioj of each cell on the grid j using the following formula:

[0087] Ecyioj = Pp Order oti/lojo

[0088] Step S304, sort the Ecyioj (for example, in descending order).

[0089] Step S305: Set the cells corresponding to the largest Ec/Io as a candidate set of coverage cells located in the grid terminal:

[0090] In this step, the value of the candidate set adopts an algorithm combining the threshold value and the maximum limit, and the threshold value of Ec/Io is set first, and the number of cells with Ec./Ioj greater than the threshold value is calculated. It is K, if K>N (N is the maximum number of candidate sets designed), then the first N cells are taken as the candidate set, otherwise the first K cells are taken as the candidate set.

[0091] Step S306: Record the grid information of the current cell in the strongest cell in each cell. The strongest cell is defined as receiving

The cell with the largest Ec/Io value is the strongest serving cell of the grid.

[0092] After that, the processing ends.

[0093] The wireless network simulation method (ie, step

The network simulation process in S206).

[0094] In general, the network simulation process consists of a large two-part cycle, including: a snapshot cycle process. A snapshot can be understood as a process for the system to reach a steady state under a distribution of a given terminal. The simulation process The result is an average combination of the results of a large number of snapshots; and an iterative cycle process. A snapshot is composed of multiple iterative cycle processes. The purpose of the iterative cycle is to make the system reach a steady state. Previously, the iterative cycle algorithm used in related technologies Regardless of whether it is forward or reverse, the Monte Carlo iteration algorithm is used. However, in the D0 system, the forward resources are time-division multiplexed, so the Monte Carlo iteration algorithm is no longer applicable. The forward algorithm in this embodiment The Monte Carlo iterative algorithm is no longer used, but a new algorithm that takes into account forward scheduling and QoS. At the same time, on the basis of the Monte Carlo iterative algorithm, the reverse is based on the matching of QoS and forward. The reverse algorithm has been improved. The implementation of this method will be described in detail below.

[0095] As shown in FIG. 4, the wireless network simulation simulation method according to this embodiment includes the following processing: Step S402, perform snapshot loop initialization; Step S404, perform a reverse link rate assignment process and a forward processing process; Steps S406: Calculate the average throughput and average rate of the cell based on the QoS requirements of the service supported by the terminal; and in step S408, if the number of snapshot cycles does not reach a preset threshold, repeat steps S402 to S406.

[0096] The method can be implemented through two schemes, which will be described below respectively.

[0097] The first solution

[0098] As shown in FIG. 5, in this solution, the wireless network simulation method specifically includes the following processing:

[0099] Step S501, cyclic initialization of snapshots:

[0100] Initialization includes the following content: (1) Determine randomly distributed locations of terminals in a predetermined manner, and randomly distribute terminals within a designated geographic area in the network (for example, according to cell coverage area, cell-by-cell distribution of traffic, etc.) ). Once the distribution method is determined, the specific location of the terminal in each snapshot will be randomly determined. The number of terminals in each snapshot conforms to the Poisson distribution principle.

[0101] (2) Determine the associated cell (coverage cell candidate set) according to the grid where the terminal is located;

[0102] (3) Determine random logarithmic normal fading and random power control error information for each terminal.

[0103] Step S502, reverse link rate assignment (as shown in Figure 7);

[0104] Step S503: Use the terminal sequence that can be accessed in the reverse direction obtained from the reverse iteration result as the input condition, and perform the forward processing flow (as shown in FIG. 8), so as to obtain the terminal sequence that can meet the forward access condition at the same time. Terminal sequence.

[0105] Step S504, determine whether reverse adjustment is required, if necessary, perform step S505; if not, perform step S506.

[0106] Here, it is worth noting that in the decision process, if a terminal is deleted in the cell forward processing procedure in step S508, this terminal will be deleted from the reverse iteration terminal set, and as long as there is If at least one terminal is deleted, reverse adjustment needs to be performed.

[0107] Step S505: Execute the reverse rate adjustment algorithm. The reverse adjustment algorithm is basically the same as the reverse link rate assignment (as shown in FIG. 7). The difference is that the terminal is not randomly selected, and the terminal set is clear Yes, that is, it is selected from the reverse iteration, but does not include the terminal that is deleted in the forward processing flow;

[0108] Step S506: Calculate the forward and reverse throughput and the average rate.

CN 101653021 Β

[0109] In this step, the calculation of the average forward throughput of the cell is divided into the following situations:

[0110] Case 1: In the case that the services supported by the terminal have QoS requirements, the forward cell ρ is calculated by the following formula

Average throughput; Througput_FL =worker should-i, where P is the number of front and reverse access terminals, and 1 <p W m; j=l

[0111] Case 2: In the case that the service supported by the terminal does not have QoS requirements, calculate the average throughput of the forward cell S____________ by the following formula, where, nm is the number of forward access terminals; and

Througput?

nm

[0112] Case 3: In the case that the service part supported by the terminal has QoS requirements, the average throughput of the forward cell is calculated by the following formula: T defense. *0+ΪΧ- "where '0=ι-έlanguageΗ where'P means there is nm μ /=1 DKJ

The number of forward and reverse access terminals required by QoS, and 1 <p W m, nm is the number of forward access terminals without QoS requirements.

[0113] Among them, the average forward rate in the three cases is equal to the average throughput of the forward cell divided by the number of forward access users. Therefore, the forward average rate can be calculated by the following formula: DataRate_FL = Throughput_FL/ NumMob orders e, where NumMobile is the number of forward access users. And, the reverse average rate can be calculated by the following formula: DataRate_EL = Throughput_EL/NumMob Order e, where NumMobile is the number of reverse access users, and k

Througput^ = Υ, ThrougputRL is the average throughput of the reverse cell.

/=1

[0114] Step S507: Determine whether the number of snapshot cycles reaches a preset threshold, and if the number of cycles is not enough, continue with the next snapshot; otherwise, end all snapshot cycles. Among them, the initial values of the variables of different snapshot cycles are different, and these variables include the number of terminals, the location of the terminals, and the access sequence of the terminals, etc.;

[0115] Step S508, the processing procedure ends.

[0116] The above is a description of the first solution of this embodiment. In addition, the following second solution may also be used in actual implementation. The second solution will be described below with reference to the accompanying drawings.

[0117] The second solution:

[0118] As shown in FIG. 6, in this solution, the wireless network simulation method specifically includes the following processing:

[0119] Step 601: Perform snapshot loop initialization;

[0120] Step 602, forward processing flow (as shown in Figure 8);

[0121] Step 603: Use the forward-access terminal sequence obtained after forward processing as an input condition, and perform reverse link rate assignment (as shown in FIG. 7), so as to obtain that the reverse connection can be satisfied at the same time. Enter the terminal sequence of the condition.

[0122] Step 604: It is judged whether forward adjustment is needed, if necessary, step 605 is executed, and if not needed, step 606 is performed.

[0123] For this judgment condition, similar to the above-mentioned first solution, if there is a terminal that cannot be accessed in the reverse direction during the cell reverse link rate assignment process in step 603, the terminal is assembled from the forward terminal. In addition, as long as at least one terminal is deleted, the forward adjustment algorithm needs to be executed.

[0124] Step 605: Execute the forward adjustment algorithm. The forward adjustment algorithm and the forward processing flow (as shown in FIG. 8) are basically the same. The difference is that the terminal is not randomly selected, and the terminal set is clear, that is, yes It is selected from the forward processing procedure, but does not include the terminal that is deleted in the reverse link rate assignment procedure.

CN 101653021 Β

[0125] Step 606: Calculate the forward and reverse throughput and average rate;

[0126] Step 607: Determine whether the number of snapshot cycles reaches a preset threshold;

[0127] Finally, the processing flow ends.

[0128] FIG. 7 shows the reverse link rate assignment process in step S404 (ie, step S502 or S603). As shown in Figure 7, it mainly includes the following processing:

[0129] Step 1. Sort all terminals according to the reverse service QoS priority. The terminals with high priority services are placed in front of the sequence, the terminals with low priority services are placed behind, and the terminals without QoS requirements are randomly placed in the sequence. Finally, after the reverse access sequence of the terminal is determined, it will remain valid in each reverse iterative calculation of this snapshot; (corresponding to step S702 above)

[0130] Step 2. Perform data rate initialization for each terminal according to the terminal access sequence. Usually, the initial rate of the terminal is set to the highest rate of the system, and the data rate of the i-th terminal is set to %; (for the same step as the above step S704 )

[0131] Step 3. Calculate the rate R: the corresponding transmission power of the terminal service channel;

[0132] Step 4. Calculate the total transmission power TXi of the terminal according to the proportion of the traffic channel in the total transmission power of the terminal; (Steps 3 and 4 correspond to the above-mentioned step S706)

[0133] Step 5. Determine whether TXi exceeds the maximum transmit power threshold of terminal i. If the determination is yes, then perform step 7; otherwise, perform step 6; (corresponding to step S708)

[0134] Step 6. Determine whether the noise received by the relevant cell rises above the threshold due to the access of the i-th terminal, and if the judgment is yes, proceed to step 7; otherwise, proceed to step 10 and record that the terminal can successfully access; (Corresponding to step S710 above)

[0135] Step 7. It is judged whether the data rate of terminal i can be reduced. Here, the main basis of the judgment is that if the data rate required by the service supported by terminal i is a fixed value, the rate cannot be reduced. Step 10 is executed and recorded as terminal connection. Entry fails, otherwise go to step 8;

[0136] Step 8. Decrease% by one level according to the rate level; (Steps 7 and 8 correspond to the above step S712)

[0137] Step 9. Determine whether the% is lower than the minimum rate threshold after the rate level is reduced. If the determination is yes, it means that the terminal cannot be accessed. Step 10 is executed and the terminal access failure is recorded; otherwise, Step 3 is executed and the next time is performed Iteration

[0138] Step 10: Record the calculation result of the terminal;

[0139] Step 11. Perform the next terminal loop until the reverse rate assignment judgment of all terminals is completed;

[0140] Step 12, it is judged whether the reverse link meets the end judgment condition of this snapshot, if the judgment is yes, then step 13 is executed; otherwise, step 3 is executed.

[0141] Step 13. Output the final result, that is, the reverse access terminal sequence and the reverse access rate.

[0142] Step 14. End this snapshot cycle.

[0143] For the decision condition in step 12, the decision whether a snapshot is over is usually divided into two stages. When the convergence condition is met, for example, the increase in the reverse noise floor of the cell in two adjacent iterations is less than a certain amount of change. Threshold value, that is, when the fluctuation of the reverse noise floor of two adjacent iterations is small, the iteration is considered to be convergent and the iteration loop is exited. When the iteration does not converge, but the number of iterations has been relatively large, in order to prevent the iteration from failing to converge and the loop cannot stop, set the threshold of the number of iterations. When the number of iterations is equal to this threshold, the iteration is forcibly terminated and the cycle of the next snapshot is transferred.

[0144] FIG. 8 shows the forward processing flow in step S404 (ie, step S503 or step S602). As shown

As shown in 8, it specifically includes the following processing:

CN 101653021 Β

[0145] Step 80: Set the total number of cells within the simulation range as Ncell; (corresponding to the above step S802)

[0146] Step 81: Determine the initial cell as the cell χ, χ=1;

[0147] Step 82: Determine the terminal belonging to the initial cell x; (Step 81 and step 82 correspond to the above step S804)

[0148] Step 83, sort the terminals belonging to the cell x according to the forward service priority (the specific process of sorting is shown in Figure 9); (corresponding to the above step S806)

[0149] Step 84: Screen terminals that cannot meet the forward QoS requirements (the specific processing flow of screening is shown in Figure 10); (corresponding to the above step S808)

[0150] Step 85: Determine whether there is a terminal that cannot meet the forward QoS requirement, and according to the screening result of step 84, determine whether it is necessary to process the terminal that cannot meet the forward QoS requirement, if it is judged to be there, then go to step 86; if not , Then go to step 87; (corresponding to the above step S810)

[0151] Step 86: Process the terminal that cannot access the cell x in the forward direction. Here, the processing method can have a variety of options, for example: (1) directly delete this type of terminal from the terminal sequence; (2) from these The candidate set of the terminal selects the cell with the second lowest strength, and assigns the terminal to that cell. If there is no candidate set cell with the second lowest pilot strength, delete the terminal from the reverse iteration result. Among them, preferably , Adopt the method of directly deleting such terminals from the terminal sequence; (corresponding to the above step S812)

[0152] Step 87: Output the terminal sequence that can be accessed and the terminal that may be deleted (corresponding to the above step S814);

[0153] Step 88, χ = x+lo

[0154] Step 89: Determine whether x is less than or equal to the number of cells Ncell. If the determination is yes, it means that there are cells that have not been processed, and go to step 82; otherwise, the processing flow is ended.

[0155] FIG. 9 shows a processing flow of prioritizing the terminals in the reverse snapshot cycle result in step S806 (ie, step 83) according to forward services.

[0156] As shown in FIG. 9, it specifically includes the following steps:

[0157] Step S902: Read the terminal attributes included in this snapshot one by one, and check whether the services supported by the terminal have priority requirements;

[0158] Step S904: For ordinary terminals without priority requirements, classify them as a forward non-priority terminal set;

[0159] Step S906: For QoS service terminals with priority requirements, they are classified as a forward priority terminal set;

[0160] Step S908: After traversing all the terminals, the terminals in the priority terminal set are sorted according to priority and placed at the front of the terminal sequence, and the terminals in the forward non-priority terminal set are randomly sorted, and It is placed at the back end of the terminal sequence to determine the access sequence of all terminals in this snapshot;

[0161] Finally, the processing flow ends.

[0162] FIG. 10 shows the process of screening the set of terminals that cannot be accessed in the forward direction in step S808 (ie, step 84). As shown in Figure 10, it specifically includes the following processing:

[0163] Step S1002, the terminals of the cell are sorted according to the forward service priority, and the set of terminals that cannot be accessed is counted as 0.

[0164] Here, it can be assumed that there are n terminals belonging to cell i, which are sorted from high to low priority as ΑΤι, ΑΤ2...

... +"< 1

Dg ... + Electricity=]

Dg ... +Euphu>1

DRC.

ΑΤη, its DRC rates are respectively denoted as DRC], DRC2...DR. Among them, ΑΊ\ to AR belong to the forward priority terminal set, and its QoS requirements are denoted as Rflt to Rfe, and AT_m+1To AT_nIt belongs to the forward non-priority terminal set.

[0165] Step S1004, set P=1; the number of terminals with QoS requirements is M, and this step is mainly to initialize the following calculations;

[0166] Step S1006: Determine whether P is greater than M. If P is greater than M, the process proceeds to step S1010; if P is less than or equal to M, the process proceeds to step S1008. Here, P greater than M indicates that all those with QoS requirements The terminals have been scanned, and the terminals without QoS requirements do not need to judge whether they meet the requirements;

[0167] Step S1008: Determine whether the following formula holds for the first P terminals with QoS requirements;

RR

[. His formula ++

[. His formula 2: black + certificate +

[Net formula 3: number + black +

[0171] Here, it should be noted that in Formula 1, Formula 2, and Formula 3, the left-style accumulation needs to delete the terminals in the terminal set that cannot be accessed in the forward direction;

[0172] When formula 1 is satisfied, that is, when the cumulative sum is less than 1, it means that the forward direction can carry P terminals and previous terminals, and there is also ample capacity to carry non-QoS terminals. At this time, P=P+1 is executed, and the processing is performed Go to step S1006;

[0173] If the formula 2 holds, that is, when the cumulative sum is equal to 1, it means that the P terminal and the previous QoS terminal can just be carried in the forward direction, and cannot carry any other terminals at the same time. All terminals after the terminal P are put into the inaccessible terminal set, including QoS and those without QoS requirements, and the process proceeds to step S1010 (output of the accessible terminal sequence and the inaccessible terminal sequence).

[0174] When formula 3 is satisfied, that is, when the cumulative sum is greater than 1, it indicates that the terminal P cannot be accessed, and the terminal P needs to be placed in the set of terminals that cannot be accessed in the forward direction. At this time, the terminal after P still has the possibility of access, so it does not exit the loop, executes P=P+1, and the process proceeds to step S1006;

[0175] Step S1010: Output the accessible terminal sequence and the inaccessible terminal sequence, and the sum of the two is the total number of terminals in the cell at the beginning of the process.

[0176] Finally, the processing flow ends.

[0177] In the following, with reference to FIG. 2, a simulation process of a CDMA2000-1X EVDO network is taken as an example to describe in detail the specific implementation steps of the present invention.

[0178] The specific implementation steps are as follows:

[0179] (1) Import a three-dimensional electronic map, including elevation, features and vector information. Enter the base station, terminal, carrier, power and other information of the network in batches or one by one.

[0180] (2) Take a general urban environment as an example. Generally, when the path loss of a certain point reaches 200dB, it is considered that the point is far enough from the cell transmitting the signal. Therefore, 200dB is set as the threshold, and the path loss of each cell is calculated. The path loss of all surrounding grids that are less than or equal to the threshold, and the path loss matrix of each cell is formed.

[0181] (3) Calculate the pilot signal-to-noise ratio Ec/IOj of each grid relative to each cell, where Eq is the pilot energy per chip from the i-th cell, 1. : Is the total received power on the grid.

[0182] Among them, i = 1, ..., M, l0j=£[0i Μ = 20 (in a general urban environment)

[0183] In this step, the values of the pilot signal-to-noise ratio calculated on each grid are sorted, and the N largest ones are selected as the candidate set of coverage cells located at the terminal of the grid, usually N=6. For the one with the largest pilot signal-to-noise ratio in the candidate set of coverage cells, mark it in its corresponding cell, that is, the corresponding grid of the path loss file matrix of the strongest serving cell.

[0184] (4) Calculate the forward demodulation signal-to-noise ratio for/ioc of each grid, and obtain the maximum rate DRC supported by each grid by querying Table 1 below. The following is the corresponding relationship between the forward demodulation signal-to-noise ratio threshold and the DRC rate under the condition of Additive WhiteGaussian Noise (AWGN):

[0185]

<td>Data rate (kbps)</td><td>DRC value</td><td>Slot</td><td>Ior/Ioc (PER=1%) AWGN</td>

<td>3&amp;4</td><td>1</td><td>16</td><td>-11.4</td>

<td>76.8</td><td>2</td><td>8</td><td>-8.6</td>

<td>153.6</td><td>3</td><td>4</td><td>-5.6</td>

<td>307.2</td><td>5</td><td>4</td><td>-2.5</td>

<td>307.2</td><td>4</td><td>2</td><td>-2.5</td>

<td>614.4</td><td>7</td><td>2</td><td>0.5</td>

<td>614.4</td><td>6</td><td>1</td><td>0.7</td>

<td>921.6</td><td>8</td><td>2</td><td>3.2</td>

<td>1228.8</td><td>10</td><td>2</td><td>5.9</td>

<td>1228.8</td><td>9</td><td>1</td><td>5.5</td>

<td>1536</td><td>13</td><td>2</td><td>8.11</td>

<td>1843.2</td><td>11</td><td>1</td><td>10.8</td>

<td>2457.6</td><td>12</td><td>1</td><td>15.4</td>

<td>3072</td><td>14</td><td>1</td><td>20.45</td>

[0186] Table 1

[0187] Table 1 comes from the minimum test standard "Recommended Minimum Performance Standards for cdma2000 High Rate Packet Data Access Termina1".

[0188] (5) Assuming that the services supported by the network have 1.2 Mbps, 300 kbps, 112 kbps QoS requirements for the data rate, and the ratio of the services is 1: 2: 1, then the three terminal types are set to correspond to these three services. , And the number ratio of the three types of terminals is also 1: 2: 1, even if a certain terminal can support multiple services in practice, it is also set separately in the simulation, which is convenient for the distribution of traffic.

[0189] (6) Initialize snapshot parameters, including the number of terminals, distribution locations, etc.

[0190] (7) Perform reverse rate assignment (as shown in Figure 6), determine the reverse access sequence of the terminal according to the QoS priority of the service supported by the terminal, and iteratively determine the reverse connection of each terminal in the terminal access sequence. Input rate and failure information, and get the terminal sequence of reverse successful access.

[0191] (8) Determine whether the terminal successfully accessed in the reverse direction needs to support services with QoS requirements in the forward direction. If not, skip directly to (11) and calculate the average throughput of the forward reverse cell; if judged If yes, go to (9).

[0192] (9) Here, a certain assumption is used to illustrate the forward QoS requirement processing algorithm in the process of a snapshot.

[0193] Assuming that there are 6 terminals successfully connected in the reverse direction, according to whether the forward service has QoS requirements and the QoS requirements

The priority is sorted from high to low to get the terminal sequence AT^AT₂.....AT₆o Set AT] to AT₄It is a terminal with QoS requirements in the forward direction, AT₅And AT₆It is an ordinary service terminal without QoS requirements, as shown in Table 2 below: [0194]

<td>Terminal number</td><td>ΑΤι</td><td>at₂</td><td>at₃</td><td>at₄</td><td>at₅</td><td>ΑΓ₆</td>

<td>QoS requirements for forward services</td><td colspan="3">Have</td><td colspan="3">no</td>

<td>Forward business priority</td><td>1</td><td>1</td><td>2</td><td>3</td><td>/</td><td>/</td>

<td>Forward QoS requirements support data rate (bps)</td><td>200k</td><td>500k</td><td>100k</td><td>300k</td><td>/</td><td>/</td>

<td>DRC data rate (bps)</td><td>1.2288M</td><td>2.4576M</td><td>307.2k</td><td>921.6k</td><td>307.2k</td><td>153.6k</td>

<td>[0195][0196]</td><td>Table 2 substituting the above assumptions into formula 1 to formula 3, we can get:</td>

<td>[0197]</td><td>Rfl-1 + Rfl-2 + ... + Rfl-pDRC] DRC₂ DRC_p</td>

<td>[0198]</td><td>One Rfl-i [Rfl-2 | Rfl-3) ^fl-4 ~ DRC] DRC₂ DRC₃ DRC₄</td>

<td>[0199]</td><td>200 500 100 300— + + +1228.8 2457.6 307.2 921.6</td>

<td>[0200][0201][0202]</td><td>«1.0173&gt;1 Among them, when Ρ = 3, there is</td>

<td>[0203]</td><td>Rfl-i] Rfl"2] Rfl.3DRC] DRC₂ DRC₃</td>

<td>[0204]</td><td>200 500 100= + +122&amp;8 2457.6 307.2</td>

<td>[0205][0206][0207]</td><td>«0.692&lt;1 Therefore, in order to satisfy the three terminals with high priority in the forward business, AT] to ΑΤ₃QoS requirements, AT is not allowed₄of</td>

Forward access. At the same time, since the forward capacity is not saturated after the access from AT] to AT3, it is still possible to access the normal terminal AT₅And AT₆, That is, the final forward access terminal sequence consists of ΑΊ\, AT?, AT3, ΑΤ₅And ΑΤ₆composition.

<td>[0208][0209]</td><td>(10) Using the above terminal sequence as the terminal sequence for reverse access, re-execute the iteration of reverse rate assignment. Suppose the reverse terminal rate after iteration is shown in Table 3 below:</td>

[0210]

<td>Terminal number</td><td>ΑΤι</td><td>at₂</td><td>αγ₃</td><td>at₅</td><td>at₆</td>

<td>Data rate after reverse adjustment (bps)</td><td>76.8k</td><td>307.2k</td><td>76.8k</td><td>153.6k</td><td>38.4k</td>

[0211] Table 3

[0212] (11) Calculate the average throughput of the forward reverse cell:

[0213] According to the assumptions of Table 2 and Table 3, the third case is compounded, that is, the access terminal sequence is the union of the terminal with QoS service in the forward direction and the terminal without QoS.

[0214]

[0215]

[0216]

[0217]

[0218]

[0219]

[0220]

[0221] Bringing the values in Table 2 into the formula τ Defenseο% = *ρ+ beg Rfl j, the former nm can be obtained

Througput_FL Average cell throughput in nm direction: η

£drg _p *0+£Populari=\workdrc, ₃ 3 =-*(1One£-^-)+£heart i set DRC, set=3°7: 2 power + 153.6 mounds*(] _ ο 692)+(20(R + 500k +100k) =870.96kbps Incorporate the values in Table 3 into the formula τ. Cough such as = soil Rg'can get U reverse average cell throughput:

/=1 ρ η

Througput^ = £ R^-i + workRrlt /=1 i~m+\

[0222] = 76. gaze intently + 307.2 mounds + 76.8k + 153.6Λ + 3&amp;4 mounds

[0223] = 652.8kbps

[0224] (12) Calculate the forward and reverse average rate:

[0225] Forward Average Rate = Forward Cell Average Throughput/Number of Forward Access Users

[0226] = 870.96k/5

[0227] = 174. 192kbps

[0228] Reverse average rate=average throughput of reverse cell/number of reverse access users

[0229] = 652.8k/5

[0230] = 130. 56kbps

[0231] (13) Determine whether the number of snapshot cycles reaches a preset threshold. If the number of times is not enough, change the initial variables of the snapshot cycle, that is, change the number of terminals, positions, access sequence, and other information, and continue the next snapshot. Otherwise, all snapshot cycles are ended.

[0232] (14) Perform statistical average of the results of all snapshot cycles, output a simulation graph, and end the simulation.

[0233] In summary, the present invention improves the traditional front-end technology for CDMA2000-1X EVDO air interface technical features such as forward full power transmission, QoS requirements for some forward services, forward business scheduling, rate control, etc. Reverse iterative process, and introduce the processing method for the business with QoS requirements, and simulate the dynamic scheduling strategy with the approximate static method, which solves the defect that the traditional simulation method cannot obtain the average forward rate and the average throughput of the cell. With the help of the technical scheme of the present invention, the wireless network simulation can be brought close to the network status of the actual EVDO system to a great extent, and the EVDO network planning and optimization work can be guided more efficiently.

[0234] The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

CN 101653021 Β