WO2006005223A1

WO2006005223A1 - The method of dynamic adjusting for the spreading factor in the wcdma system

Info

Publication number: WO2006005223A1
Application number: PCT/CN2004/000782
Authority: WO
Inventors: Lirong Shi; Jianwu Dou
Original assignee: Zte Corporation
Priority date: 2004-07-12
Filing date: 2004-07-12
Publication date: 2006-01-19
Also published as: CN101015152A; CN101015152B

Abstract

The invention relates to a method of dynamic adjusting for the spreading factor in the WCDMA system. The method includes the steps as follows: after the user's service in the packet switched field is created, distributing the initial resources to the user; the control plane sending the test control commands; the user plane and the base station performing the corresponding test based on the test commands, if the report condition is satisfied, the test report being send to the control plane; the control plane receiving the report results, setting the corresponding counter or timer, only if the counter is above the counting threshold valueor the timer is overtime, the decision being adjusted; the control plane determining whether the rate and the spreading code should be adjusted, and sending the command to the user plane and the base station, the user plane and the base station performing the corresponding adjust based on the command. By way of the invention method, preferably eliminates the burst of the traffic volume and the transmission relay of the network, improves the throughput of the data traffic; reasonably makes use of the code resource and the power resource, improves the coverage range of the system downlink and reduces the interference among the uplink users, thereby increases the system capacity.

Description

Method for dynamically adjusting spreading factor in wideband code division multiple access system

The present invention relates to a method for dynamically adjusting a spreading factor in a Wide Code Division Multiple Access (WCDMA) system, in particular, according to a change in a Transport Channel Traffic Volume (TCTV). In the case, a specific method of dynamically adjusting the spreading factor (Spreading Factor, hereinafter referred to as SF) of the dedicated channel. Background technique

With the rapid development of communication technology, the third generation of mobile communication systems is gradually on the historical stage. A prominent feature of the third-generation communication system is that it not only supports the voice service in the traditional Circuit Switched (CS) connection mode, but also supports the data in the Packet Switched (PS) connection mode. business. Videophones, online browsing, video on demand, file downloads, and e-mail are increasingly used. However, the characteristics of these user applications vary greatly. In addition to the continuous transmission of streaming media such as video conferencing and online on-demand, online games, online browsing, file downloading, etc. all have sudden characteristics, that is, very short in a short period of time. A large amount of data, and then there is almost no data transmission for a long time.

Due to this suddenness of data services, some measures have been taken on the network, such as the Transmission Control Protocol (TCP), which is often used on the network today. From the perspective of wireless communication performance, the biggest feature of TCP is flow control, which uses congestion window and supply window to achieve flow control. The amount of data sent depends on the monitoring of the degree of congestion. If TCP detects packet loss, it reduces the transmission rate and then slowly increases the gradually increasing throughput. This congestion response mechanism will affect the throughput of wireless networks. Currently, WCDMA technology has become a widely adopted third-generation air interface. WCDMA systems can provide transmission rates from a few thousand bits per second to several megabits per second, supporting multiple CS and PS services. Two very important radio resources supporting these services in WCDMA are channelization codes and transmit power channelization codes for distinguishing transmissions from the same cell, ie, downlink connections of one sector, and from a certain terminal. All uplink dedicated channels. There are certain restrictions on the channelization codes used by the same information source. The physical channel must adopt a channelization code that must satisfy: the lower branch of the code tree All codes are not used, that is, all high-order spreading factor codes after this code cannot be used. Similarly, low-order spreading factor codes from this branch to the root of the tree cannot be used. It can be seen that the downlink channelization code resources are limited, and the higher the transmission rate, the smaller the corresponding spreading factor, and the more blocked channelization codes.

Another important resource is the transmit power. Interference caused by the signature of different users on the uplink of the carrier frequency can degrade the communication quality, especially when the power of the interference signal is much larger than the power of the signal to be detected. In order to reduce interference between users, power control is used. However, in the process of moving, the user equipment (User Equipment, hereinafter referred to as UE) is in a changing environment. When the UE is far away from the base station or the wireless environment is deteriorated, if the original rate is still maintained, To ensure the quality of the call, under the effect of closed-loop power control, the base station will inevitably send signals with greater power. The impact of the power change at this time is relatively large, and the power of many UEs may rise. This will lead to a sharp increase in power, so that the wireless environment will further deteriorate, and the capacity of the system will also decrease. Sometimes, even if the UE's power is increased to the limit, the call quality cannot be improved.

Compared with the Global System for Mobile Communications (GSM) and other existing mobile networks, the WCDMA system has many special features. Soft capacity and support for variable rate services are a major feature. If the system can dynamically adjust the spreading factor and the data service transmission rate during the system operation, the system can reduce the downlink code resource limitation and reduce the base station transmission power. For the user, adapt to the dynamic characteristics of the service traffic, improve service quality. Invention disclosure

The object of the present invention is to provide a method for dynamically adjusting a spreading factor during operation of a WCDMA system, including a specific implementation of a decision and adjustment, so as to better eliminate burstiness of service traffic and network propagation delay, and improve data traffic throughput. The quantity and the reasonable use of code resources and power resources improve the downlink coverage of the system and reduces the interference between uplink users, thereby increasing the system capacity.

To achieve the above object, a method for dynamically adjusting a spreading factor in a wideband code division multiple access system proposed by the present invention includes the following steps:

Step 1: After establishing a user's PS domain service, allocate initial resources to the user; Step 2: The control plane sends a measurement control command;

Step 3: The user plane and the base station perform corresponding measurement according to the measurement command, if the report is satisfied Piece, send a measurement report to the control surface;

Step 4: The control plane receives the report result, and sets a corresponding counter or timer. The adjustment decision is made only when the counter exceeds the count threshold or the timer expires;

In step 5, the control plane determines whether to adjust the rate and the spreading factor, and sends commands to the user plane and the base station to perform corresponding adjustments through the user plane and the base station.

The method for dynamically adjusting a spreading factor in the wideband code division multiple access system, in step 1, when establishing a PS domain service of a user, performing a radio access bearer assignment request, and allocating dedicated channel resources after receiving, Specify the initial rate.

The method for dynamically adjusting a spreading factor in the wideband code division multiple access system, in the second step, the control plane sends a measurement control command, including a measured physical quantity and a reporting manner, where the reporting manner includes a periodic reporting manner and The event triggers the reporting mode. For the periodic reporting mode, the measurement control command further includes a measurement parameter such as a reporting period and a lag time. For the event triggering reporting mode, the measurement control command further includes a measured parameter such as a threshold and a triggering time.

The method for dynamically adjusting a spreading factor in the wideband code division multiple access system, wherein the measurement parameter can be obtained by integrating measurement or simulation means by factors such as a cell load and a user's Qos.

In the method for dynamically adjusting the spreading factor in the wideband code division multiple access system, in step 4, if the event triggering reporting mode is adopted in the third step, if the counter is used to adjust the judgment, each time the reported 4A is received or In the 4B event, the corresponding counter is incremented by 1, and the counter of the relative event is cleared to 0. Only when the counter exceeds the counting threshold, further adjustment decision is made; if the timer is used for the judgment, the first reported 4A is received. Or the corresponding timer is started when the 4B event is started, and the timer of the relative event is stopped. In the process of the timer timeout, the measurement report of the relative event has not been received, and further adjustment judgment is performed.

In the method for dynamically adjusting the spreading factor in the wideband code division multiple access system, if the event trigger reporting mode is adopted in the third step, in step 5, the specific implementation steps are as follows:

The initial parameters are preset, and the initial parameters include a spreading factor adjustment range, 4A and 4B event reporting thresholds, a counting threshold, a dedicated TCP threshold, and a cell load allowable threshold;

The control plane performs adjustment decisions according to the reported 4A and 4B events respectively, and determines whether to adjust the spreading factor. If adjustment is needed, the user plane and the base station are sent commands to directly perform the spreading factor adjustment.

The method for dynamically adjusting a spreading factor in the wideband code division multiple access system, if the reported 4A The event determines whether the 4A counter exceeds the counting threshold; if the counting threshold is not exceeded, the 4A counter is incremented by 1, and the corresponding 4B counter is cleared to 0, exiting for the next measurement; if it has been exceeded The counting threshold value is selected within the range of the spreading factor adjustment range, and the corresponding adjustment command is sent to adjust, otherwise the next measurement is exited.

The method for dynamically adjusting a spreading factor in the wideband code division multiple access system, in the case that the 4A counter exceeds the counting threshold, adopts a principle of stepwise down-regulation, and further includes the following steps:

Determining whether a cell can provide a code resource corresponding to the adjusted spreading factor;

Whether the cell load is less than the cell load allowable threshold;

The dedicated TCP measurement does not exceed the dedicated TCP threshold;

If all of the above conditions are met, the down-conversion factor is selected within the range of the spreading factor adjustment, and the corresponding adjustment command is sent for adjustment.

The method for dynamically adjusting a spreading factor in the wideband code division multiple access system, if a 4B event is reported, determining whether the 4B counter exceeds the counting threshold; if the counting threshold is not exceeded, 4B is The counter is incremented by 1, and the corresponding 4A counter is cleared to 0, and the next measurement is exited. If the counting threshold has been exceeded, the up-scaling factor is directly selected within the range of the spreading factor adjustment, and the corresponding transmission is performed. Adjust the command to adjust.

In the method of dynamically adjusting the spreading factor in the wideband code division multiple access system, in step 4, if the periodic reporting mode is adopted in the third step, when the measurement report is received, the corresponding thresholds of the 4A event and the 4B event are required. The value is compared to determine whether a 4A event or a 4B event has occurred; and, if a counter is used to make an adjustment decision, each time the reported 4A or 4B event is received, the corresponding counter is incremented by 1 and the counter of the relative event is cleared. Further adjustment decision is made only when the counter exceeds the count threshold; if a timer is used for the decision, the corresponding timer is started when the reported 4A or 4B event is received for the first time, and the timer of the relative event is stopped. During the timeout period of the timer, no measurement report of the relative event has been received, and further adjustment decisions are made.

In the method for dynamically adjusting the spreading factor in the wideband code division multiple access system, if the periodic reporting mode is adopted in the third step, in the fifth step, the specific implementation steps are as follows:

Presetting initial parameters, including a spreading factor adjustment range, a rate adjustment set, a reporting period, a lag time, a counting threshold, a dedicated TCP threshold, and a cell load allowable threshold;

The control plane performs adjustment decisions according to the reported 4A and 4B events, and determines whether to adjust the spreading factor. If adjustment is needed, the data rate is adjusted first, and then the spreading factor is indirectly triggered. Whole.

The method for dynamically adjusting a spreading factor in the wideband code division multiple access system, if a 4A event is reported, determining whether the 4A counter exceeds the counting threshold; if the counting threshold is not exceeded, The 4A counter is incremented by 1, and the corresponding 4B counter is cleared to 0, and the next measurement is exited. If the counting threshold has been exceeded, the data rate is adjusted first, and then the spreading factor adjustment is indirectly triggered.

The method for dynamically adjusting a spreading factor in the wideband code division multiple access system, wherein the step of adjusting a data rate first and then indirectly triggering a spreading factor adjustment comprises the following steps:

Determining whether there is an adjustable rate in the preset rate adjustment set; whether the cell load is less than the cell load allowable threshold;

The dedicated TCP measurement does not exceed the dedicated TCP threshold;

If all of the above conditions are met, the rate is increased, and the spreading factor is determined;

If the value of the spreading factor does not change, only the rate is adjusted, and the spreading factor is not required to be adjusted; if the value of the spreading factor changes, and the cell can provide a code resource corresponding to the spreading factor, then the expansion Select the down-conversion factor within the frequency factor adjustment range, send the corresponding adjustment command to adjust, otherwise exit the next measurement.

The method for dynamically adjusting a spreading factor in the wideband code division multiple access system, if a 4B event is reported, determining whether the 4B counter exceeds the counting threshold; if the counting threshold is not exceeded, 4B is The counter is incremented by 1, and the corresponding 4A counter is cleared to 0, and the next measurement is exited. If the counting threshold has been exceeded, the data rate is adjusted first, and then the spreading factor adjustment is indirectly triggered.

Determining whether there is a rate that can be down-regulated in the rate adjustment set;

If not, do not make any adjustments and exit for the next measurement;

If there is a rate that can be down-regulated, the rate is lowered, and the spreading factor is determined;

If the value of the spreading factor is unchanged, only the rate is lowered, and the spreading factor is not adjusted;

If the spreading factor changes, the up-scaling factor is selected within the range of the spreading factor adjustment, and the corresponding adjustment command is sent for adjustment.

The method for dynamically adjusting a spreading factor in the wideband code division multiple access system, by updating the current The transmission format combination set used determines the transmission format combination corresponding to the maximum rate, and determines the spreading factor in combination with the coding mode, the downlink multiplexing mode, the configuration of the transmission channel, and the like.

The method for dynamically adjusting a spreading factor in the wideband code division multiple access system, where the rate adjustment set may be determined based on a radio access capability of a user equipment and a corresponding transport format combination set when the connection is initially established, and combined according to a transmission format The set determination rate is calculated according to the following pseudo code - Rate = 0;

For i = 1 to N

Rate = TB_ Size[i] * TB_Number[i] / TTI[i] + Rate;

End;

In the above formula, Rate represents the rate corresponding to a certain transport format combination, N represents the number of transport formats included in the transport format combination, and TB_Size[i] represents the size of the transport block in the transport format labeled i, TB— Number[i] represents the number of transport blocks in the transport format labeled i, and TTI[i] represents the transmission interval in the transport format labeled i.

The method for dynamically adjusting a spreading factor in the wideband code division multiple access system, where the scaling factor adjustment range may be determined based on a radio access capability of a user equipment and a Qos parameter included in a connection establishment request message;

The 4A and 4B event reporting thresholds may be 100% according to the total buffer area of a corresponding transmission channel, or dynamically adjusted according to the actual load of the cell during system operation;

The counting threshold may be initially set to a value between 3 and 7, and the counting threshold may be adjusted again according to the load condition of the cell and the service throughput of the dedicated channel during system operation; The load allowable threshold may take a value in the cell overload recovery threshold and the cell overload threshold;

The dedicated TCP threshold can be combined with power control, which is not greater than the maximum transmit power of the base station to a single user. BRIEF DESCRIPTION OF THE DRAWINGS

1 is a structural diagram of a radio protocol layer in a WCDMA system to which the method is applied; FIG. 2 is a general flowchart of a method for controlling runtime of the system of the present invention;

Figure 3 is a flow chart of the first embodiment of the present invention;

Figure 4 is a flow chart of a second embodiment of the present invention. The best way to implement the invention

The method of the present invention is directed to PS domain services in a dedicated connection mode.

It is stipulated in the 3GPP protocol that there are two types of measurement reporting methods: periodic reporting and event triggering reporting. The following methods of the present invention mainly describe the event triggering reporting manner, but the same applies in the periodic reporting mode.

Several concepts involved in the TCTV measurement process are as follows:

Event 4A: The traffic of the transport channel is greater than an absolute threshold, which is called 4A event.

Event4B: The traffic of the transport channel is less than an absolute threshold, which is called 4B event.

The dynamic adjustment method described in the present invention specifically includes the following steps:

The first step is to allocate an initial resource to the user after establishing a PS domain service of the user. In the second step, the control plane sends a measurement control command, where the measurement command includes the measured physical object, the measurement parameter, the reporting mode, and the like. Periodic reporting, then the corresponding measurement period, hysteresis time, etc.; if the event is triggered to report, including the upper and lower thresholds of the trigger. Measurement reporting conditions The parameters involved, such as measurement period, hysteresis time or upper and lower thresholds, can be combined with factors such as cell load and user Qos, and obtained through actual measurement or simulation.

In the third step, the user plane and the NodeB (base station) perform corresponding measurement according to the measurement command, and if the reporting condition is met, send a measurement report to the control plane;

In the fourth step, the control plane receives the report result and sets the corresponding counter. Only when the counter exceeds the count threshold, the adjustment decision is made. The counting threshold can be set to a value of 3 to 7, and then the fifth step is performed by referring to the load condition of the cell and the service throughput of the dedicated channel during system operation, and the control plane determines whether to adjust the rate and SF, and Send commands to the user plane and NodeB, and the user plane and NodeB adjust accordingly.

The reason why the counter is used in the fourth step is because of the sudden nature of the data service. Perhaps the traffic volume is less than or greater than the set threshold is only temporary. The amount of data in the buffer may be due to the rate adjustment, or The increased or decreased capacity of the connection requires rapid accumulation or sharp decline. In this way, it is very likely that the reverse condition will be satisfied and cause another adjustment, thereby causing a "ping-pong effect", which is very disadvantageous for both the user and the system. Because every time the rate changes, the reconfiguration of the link will disappear. The terminal battery is used to increase the extra signaling overhead of the system and easily cause packet data loss. In order to avoid this situation, the method uses a counter. Each time the reported 4A or 4B event is received, the counter is incremented by one, and the counter of the relative event is cleared to 0. Only when the counter exceeds a certain value is further performed. Judgment.

A timer can also be used to start the timer the first time it receives a 4A or 4B event. The timing can be preset with reference to the cell load and the service throughput of the dedicated channel, and can be adjusted during system operation. If no measurement report of the relative event is received during the timer start-up timeout, then a further decision is made.

In the fifth step, the control plane makes adjustment judgments, which are divided into 4A events and 4B events. The judgment conditions of the two are different.

The 4A event reported by the user indicates that the traffic is too high, which is the trigger condition for the SF to be lowered. According to the principle of channelization code resource allocation, after the SF is reduced, it will occupy more resources. First, it is necessary to judge whether the cell can provide suitable code resources. It includes not only the own cell but also an intra-frequency cell and an inter-frequency cell. At the same time, the SF is down-regulated, the transmission rate is increased, the transmission power of the base station is increased, and the interference between users is also enhanced. Therefore, the cell load control and power control are combined, so that the adjusted cell is not overloaded, and the dedicated transmission power of the base station cannot be higher than The maximum power value of a single user limits the mutual interference between users.

The 4B event reported by the user indicates that the traffic is too low, and the adjustment on the SF saves the use of channelization code resources. After the SF increases, the corresponding transmission rate decreases, and the transmission power is reduced, and the decision of the uplink adjustment can be made.

In the present invention, two specific implementation methods for performing SF adjustment in a WCDMA system are mainly introduced. One is to directly perform SF adjustment according to the judgment, and the other is to convert according to the decision to adjust the data rate, indirectly triggering the SF. Adjustment.

According to the above idea in the present invention, the specific implementation method is not limited to these two, and there are also some different methods in the implementation details of the two. However, it is within the scope of the invention.

The implementation of the technical solution will be further described in detail below with reference to the accompanying drawings.

FIG. 1 is a structural diagram of a wireless protocol of WCDMA used in the application of the method.

The role of the radio interface protocol is to establish, reconfigure, and release radio bearer services. The bottom-up is called the physical layer (layer 1), the data link layer (layer 2), and the network layer (layer 3). From the control point of view, layer 2 contains two sub-layers: the Medium Access Control (MAC) protocol layer and the Radio Link Control (RLC) protocol layer. From the user's perspective, in addition to the MAC layer and the RLC layer, there are two Service-dependent protocol layers: Packet Data Convergence Protocol (PDCP) and Broadcast/Multicast Control Protocol (BMC). Layer 3 contains δ The Radio Resource Control (RC) belongs to the control plane.

The physical layer provides information transmission services over the air interface and performs the following functions: forward error correction coding and decoding, macro diversity distribution/combination, handover execution, error detection, multiplexing and demultiplexing of transport channels, and transmission channel to physical channel. Mapping, modulation, demodulation, spread spectrum, despreading, power control, frequency and time synchronization, and more.

The MAC layer provides unacknowledged transmission of traffic data units between peer MAC entities. The MAC layer function selects the appropriate transport format for each transport channel, depending on the data rate. Priority processing between one user's data streams and between different users' data streams, control message scheduling, higher layer PDU multiplexing and demultiplexing, and other functions. Specifically, the MAC layer performs reconfiguration of the transport format and the radio bearer.

The RLC layer performs various functions, including the establishment, release, and maintenance of RLC connections, PDU segmentation, assembly, cascading, retransmission, repetitive monitoring, flow control, and other functions. A buffer for transmitting data that is assigned to the user connection exists at the RLC layer.

The PDCP exists only in the packet switched service, and the BMC is used to transmit the wireless interface message generated by the cell broadcast center.

The control plane portion of the network layer in UTRAN consists of a radio resource control protocol. The RRC layer allocates radio resources and processes control commands over the radio interface, such as control commands for radio access bearers, measurement reports, and reconfiguration commands.

The occupancy of the service data transmission buffer in the example algorithm of the present invention is reported to the MAC layer by the RLC layer, and the measurement control and SF adjustment decisions are performed by the RRC layer. The traffic statistics and SF adjustment are performed by the MAC layer.

Figure 2 shows the overall flow chart of the system runtime control method.

When adding or creating a new connection, the message specifically represented by the Iu interface (the standard interface in the 3GPP: the interface between the access network and the core network) is: RAB (Radio Access Bearer) message assignment request (step 201) , perform admission control, allocate resources, and specify an initial rate (step 202). The RRC layer sends a measurement control command requesting a common measurement TCP (Transmitted Carrier Power) reflecting the cell load, a dedicated measurement TCP (Transmitted Code Power), and a capacity of the transmission buffer RLC BO (step 203). . The RRC layer receives the measurement result and saves it locally (step 204). The RRC layer decides whether to make an adjustment, thereby entering the dynamic adjustment algorithm (step 205) while performing the next measurement (step 206). FIG. 3 and FIG. 4 show two implementation examples, which respectively correspond to the direct adjustment of the SF instance, and the SF adjustment example triggered by the rate adjustment, which corresponds to step 205 in FIG. 2 .

Figure 3 is a flow chart of Example 1.

The initial parameters are set in advance, including: SF adjustment range, 4A, 4B event reporting threshold, counting threshold, cell load allowable threshold, dedicated TCP threshold (step 301).

The SF adjustment range may be determined based on the radio access capability of the UE and the Qos parameter included in the connection setup request message.

The 4A and 4B event reporting thresholds may be a percentage according to the total buffer area of a corresponding transmission channel, for example, the 4A event threshold corresponds to 90%, the 4B event threshold corresponds to 50%, or dynamically adjusted according to the actual load of the cell during system operation. In order to better improve the user's QoS.

The count threshold can be determined in accordance with the method shown in the above summary.

The cell load allowable threshold is set. In order not to affect the load control algorithm, a value may be taken in the cell overload recovery threshold and the cell overload threshold.

The dedicated TCP threshold can be combined with power control, which is not greater than the maximum transmit power of the base station to a single user. The RRC layer separately judges according to the reported measurement result, if a 4A event occurs (step

302), determining whether the 4A counter has exceeded the set threshold (step 304), if not exceeded, then adding the 4A counter to 1 and clearing the corresponding 4B counter to 0, the purpose of which is only when the 4A event occurs continuously When it is fixed at a certain value, it can effectively avoid the ping-pong effect of up-regulation and down-regulation in the case of traffic oscillation (step 307). If the threshold is exceeded, it indicates that the 4A event has reached the adjusted threshold. The SF is selected within the SF adjustment range. For simplicity, the principle of step-by-step adjustment can be used to determine whether a cell can provide corresponding adjustment. The code resource of the subsequent SF (step 306), whether the cell load is less than the threshold for allowing adjustment (step 309), and the dedicated TCP measurement does not exceed the threshold (step 310), and if all are satisfied, the decision of the SF down adjustment is made (step 311). And sending a corresponding adjustment command, which may be a physical channel reconfiguration, a transmission channel reconfiguration, a transport format reconfiguration, and the like (step 313), exiting (step 314).

If a 4B event occurs (step 303), similar to the occurrence of the 4A event, it is first determined whether the 4B counter has exceeded the set threshold (step 305). If not, the 4B counter is incremented by 1 and the corresponding 4A is The counter is cleared (step 308). If the threshold is exceeded, the difference from the 4A event is that because the adjustment corresponding to the 4B event is the rate of decrease and the SF is adjusted, the consumption of system resources can be reduced, so that no further judgment is needed, and the SF adjustment range is selected. Adjust the value, A decision is made to SF up (step 312), and a corresponding adjustment command may be sent, which may be a physical channel reconfiguration, a transmission channel reconfiguration, a transport format reconfiguration, etc. (step 313), exiting (step 314).

Figure 4 is a flow chart of Example 2.

The initial parameters are preset, including: rate adjustment set, 4A, 4B event reporting threshold, counting threshold, cell load allowable threshold, and dedicated TCP threshold (step 301).

The rate adjustment set may be determined based on a radio access capability of the UE and a set of transport formats corresponding to when the initial connection was established.

Calculating the rate according to the transport format combination set is calculated according to the following pseudo code - Rate = 0;

For i = 1 to N

Rate = TB_ Size[i] * TB_Number[i] I TTI[i] + Rate;

End;

In the above formula, Rate represents the rate corresponding to a certain transport format combination, N represents the number of transport formats included in the transport format combination, and TB_Size[i] represents the size of the transport block in the transport format labeled i. TB_Number[i] represents the number of transport blocks in the transport format labeled i, and TTI[i] represents the transmission interval in the transport format labeled i.

For the setting of other parameters, refer to the setting method of the initial parameters in Example 1 of Fig. 3.

The RRC layer separately determines according to the reported measurement result. If a 4A event occurs (step 402), it is determined whether the 4A counter has exceeded the set threshold (step 404), and if not, the 4A counter is incremented by 1, and The corresponding 4B counter is cleared (step 407). If the threshold is exceeded, it indicates that the consecutive 4A event reaches the set threshold of the adjustment, and it is further determined whether there is an adjustable rate in the preset rate adjustment set (step 406), whether the cell load is less than the allowable The adjusted threshold (step 409), and the dedicated TCP measurement does not exceed the threshold (step 410), if all are satisfied, the corresponding SF is determined according to the rate after the up-regulation (step 411), if the value of SF is unchanged (step 413), Then, it is only necessary to adjust the rate without adjusting the SF (step 414); if the value of the SF changes, that is, becomes smaller, and the cell can provide the code resource corresponding to the SF (step 415), then the SF is down-regulated (step 416).

If a 4B event occurs (step 403), similar to the occurrence of the 4A event, it is first determined whether the counter has exceeded the set threshold (step 405). If not, the 4B counter is incremented by 1, and the corresponding 4A counter is simultaneously Cleared to 0 (step 408). If the threshold is exceeded, judge Whether there is a rate that can be adjusted in the rate set (step 412), if not, no adjustment is made, exit (step 422), otherwise the corresponding SF is determined according to the rate after the down-conversion, and the SF is either unchanged or larger, required The channel code resources are not increased, so that there is no need to further determine the code resource condition of the cell (step 417). If SF is unchanged (step 418), only the rate is lowered, the SF is not adjusted (step 419), if it is changed, that is, it is increased, the SF is up-regulated (step 420), the corresponding adjustment command is sent (step 421), and exit (step 422). . Industrial applicability

The beneficial effects of the present invention over the prior art are that the method of the present invention is logically reasonable, efficient, and does not require any hardware resources. The control method based on the combination of service traffic and transmit power is mainly used to not only reduce the transmission delay of bursty data services, but also prevent cell overload and excessive interference between users. The dynamic adjustment of the spreading factor and the transmission rate is used, which can alleviate the limited tension of WCDMA code resources and power resources in time, and improve the system resource utilization.

The method of the present invention is mainly based on the comparison of the transmission traffic flow and the threshold value, and in combination with the cell load control and the power control, the transmission rate and the spreading factor are appropriately adjusted. Therefore, by using the method of the invention, the burstiness of the traffic flow and the network propagation delay are better eliminated, and the data service throughput is improved; and the code resource and the power resource are used reasonably, thereby improving the downlink coverage of the system and reducing Interference between upstream users, thereby increasing system capacity.

Claims

Claim

A method for dynamically adjusting a spreading factor in a wideband code division multiple access system, comprising the following steps: Step 1: After establishing a PS domain service of a user, assigning an initial resource to the user; Step 2, controlling Send measurement control commands;

Step 3: The user plane and the base station perform corresponding measurement according to the measurement command, and if the reporting condition is met, send a measurement report to the control plane;

The method for dynamically adjusting a spreading factor in a wideband code division multiple access system according to claim 1, wherein in step 1, when a PS domain service of a user is established, a radio access bearer assignment request is performed. And allocate dedicated channel resources after admission, specifying the initial rate.

The method for dynamically adjusting a spreading factor in a wideband code division multiple access system according to claim 1, wherein in the second step, the control plane sends the measurement control command, including the measured physical quantity and the reporting manner. The reporting manner includes a periodic reporting manner and an event triggering reporting manner. For the periodic reporting manner, the measurement control command further includes a measurement parameter such as a reporting period and a lag time. For the event triggering reporting manner, the measurement control command further includes Measurement parameters such as thresholds and trigger times reported.

The method for dynamically adjusting a spreading factor in a wideband code division multiple access system according to claim 3, wherein the measurement parameter can integrate factors such as a cell load and a user's QoS, and the actual measurement or simulation is performed. Means to get.

The method for dynamically adjusting a spreading factor in a wideband code division multiple access system according to claim 3, wherein in step four, if the event triggering reporting mode is adopted in step three, if a counter is used to perform the adjustment decision, Each time the Bayer receives the reported 4A or 4B event, the corresponding counter is incremented by 1, and the counter of the relative event is cleared to 0. Only when the counter exceeds the count threshold, further adjustment decision is made; When the first reported 4A or 4B event is received, the corresponding timer is started, and the timer of the relative event is stopped, and the timer expires. No further adjustments have been received until a measurement report of the relative event has been received.

The method for dynamically adjusting a spreading factor in a wideband code division multiple access system according to claim 5, wherein if the event triggering reporting mode is adopted in step 3, in step 5, the specific implementation steps are as follows:

The method for dynamically adjusting a spreading factor in a wideband code division multiple access system according to claim 6, wherein if the 4A event is reported, it is determined whether the 4A counter exceeds the counting threshold; When the counting threshold is exceeded, the 4A counter is incremented by 1, and the corresponding 4B counter is cleared to 0 to exit the next measurement; if the counting threshold has been exceeded, within the spreading factor adjustment range Select the down-conversion factor and send the corresponding adjustment command to adjust. Otherwise, exit the next measurement.

8. The method of dynamically adjusting a spreading factor in a wideband code division multiple access system according to claim </ RTI>, wherein, in the case that the 4A counter exceeds the counting threshold, the principle of stepwise down-regulation is adopted. The method includes the following steps: determining whether a cell can provide a code resource corresponding to the adjusted spreading factor;

Whether the cell load is less than the cell load allowable threshold;

The dedicated TCP measurement does not exceed the dedicated TCP threshold;

The method for dynamically adjusting a spreading factor in a wideband code division multiple access system according to claim 6, wherein if the 4B event is reported, it is determined whether the 4B counter exceeds the counting threshold; if not exceeded The counting threshold value is incremented by 1B counter, and the corresponding 4A counter is cleared to 0, and the next measurement is exited; if the counting threshold value has been exceeded, the scaling factor adjustment range is directly Select the up-scaling factor and send the corresponding adjustment command to adjust.

10. The method for dynamically adjusting a spreading factor in a wideband code division multiple access system according to claim 3. The method is characterized in that, in step 4, if the periodic reporting mode is adopted in step three, when receiving the measurement report, it is required to compare with the corresponding threshold values of the 4A event and the 4B event to determine whether a 4A event or 4B has occurred. Event; and, if the counter is used for the adjustment decision, each time the reported 4A or 4B event is received, the corresponding counter is incremented by 1, and the counter of the relative event is cleared to 0, only when the counter exceeds the count threshold. If the timer is used for the judgment, the corresponding timer is started when the reported 4A or 4B event is received for the first time, and the timer of the relative event is stopped, and the timer has not been received until the timer expires. Further adjustments are made to the measurement report of the relative event.

11. The method of dynamically adjusting a spreading factor in a wideband code division multiple access system according to claim 10, wherein if the periodic reporting mode is adopted in step 3, in step 5, the specific implementation steps are as follows:

The control plane performs adjustment decisions according to the reported 4A and 4B events, and determines whether to adjust the spreading factor. If adjustment is needed, the data rate is adjusted first, and then the spreading factor adjustment is indirectly triggered.

The method for dynamically adjusting a spreading factor in a wideband code division multiple access system according to claim 11, wherein if the 4A event is reported, it is determined whether the 4A counter exceeds the counting threshold; When the counting threshold is exceeded, the 4A counter is incremented by 1, and the corresponding 4B counter is cleared to 0, and the next measurement is exited. If the counting threshold has been exceeded, the data rate is adjusted first, and then the pair is indirectly triggered. Spreading factor adjustment.

The method for dynamically adjusting a spreading factor in a wideband code division multiple access system according to claim 12, wherein the step of adjusting the data rate first and then indirectly triggering the adjustment of the spreading factor comprises the following steps: Whether there is an adjustable rate in the preset rate adjustment set; whether the cell load is less than the cell load allowable threshold;

The dedicated TCP measurement does not exceed the dedicated TCP threshold;

If the value of the spreading factor does not change, only the rate is adjusted, and the spreading factor is not required to be adjusted; if the value of the spreading factor changes, and the cell can provide the code corresponding to the spreading factor The source selects the down-conversion factor within the range of the spreading factor adjustment, and sends a corresponding adjustment command to adjust, otherwise exits to perform the next measurement.

The method for dynamically adjusting a spreading factor in a wideband code division multiple access system according to claim 11, wherein if the 4B event is reported, it is determined whether the 4B counter exceeds the counting threshold; if not exceeded The counting threshold value increments the 4B counter by 1 and clears the corresponding 4A counter to 0 to exit the next measurement. If the counting threshold has been exceeded, the data rate is adjusted first, and then the expansion is indirectly initiated. Frequency factor adjustment.

15. The method of dynamically adjusting a spreading factor in a wideband code division multiple access system according to claim 14, wherein the step of adjusting the data rate first and then indirectly causing the adjustment of the spreading factor comprises the following steps:

If not, do not make any adjustments and exit for the next measurement;

The method for dynamically adjusting a spreading factor in a wideband code division multiple access system according to claim 13 or 15, wherein the transmission format combination corresponding to the maximum rate is determined by updating the currently used transmission format combination set. The spreading factor is determined by combining the coding mode, the downlink multiplexing mode, the configuration of the transmission channel, and the like.

The method for dynamically adjusting a spreading factor in a wideband code division multiple access system according to claim 16, wherein the rate adjustment set is based on a radio access capability of the user equipment and a corresponding transmission when the connection is initially established. The format combination set is determined, and the rate determined according to the transport format combination set is calculated according to the following pseudo code:

Rate = 0;

For i = 1 to N

Rate = TB_ Size[i] * TB_Number[i] I TTI[i] + Rate;

End;

In the above formula, Rate represents the rate corresponding to a certain transport format combination, N represents the number of transport formats included in the transport format combination, and TB_Size[i] represents the transport block in the transport format labeled i. The size, TB_Number[i] represents the number of transport blocks in the transport format labeled i, and TTI[i] represents the transmission interval in the transport format labeled i.

18. The method of dynamically adjusting a spreading factor in a wideband code division multiple access system according to claim 6 or 11, wherein:

The spreading factor adjustment range may be determined based on a radio access capability of the user equipment and a Qos parameter included in the connection establishment request message;

The dedicated TCP threshold can be combined with power control, which is not greater than the maximum transmit power of the base station to a single user.