WO2005027431A1

WO2005027431A1 - A method for controlling a wireless access based on multi-services priority in umts

Info

Publication number: WO2005027431A1
Application number: PCT/CN2003/000781
Authority: WO
Inventors: Zhiyu Xu; Huidi Li; Baijun Zhao
Original assignee: Utstarcom (China) Co. Ltd.
Priority date: 2003-09-16
Filing date: 2003-09-16
Publication date: 2005-03-24
Also published as: CN1788462A; CN100459565C; AU2003266485A1

Abstract

The present invention relates to a method for controlling a wireless access by adjusting the load and matching the rate in a 3G mobile communication system (UMTS), based on the cell wireless load and the priority of a requested access. In the case of a wireless overload in a cell, the load services in the cell are adjusted according to the different priorities, and transmission rate of the access service can be also adjusted. The number of the high priority and real time traffic is maximized to meet the requirement of the system.

Description

Multi-service based in UMTS

TECHNICAL FIELD

The present invention relates to a wireless access for performing load adjustment and rate negotiation in a third-generation (3G) mobile communication system UMTS (Universal Mobile Telecommunication System, Universal Mobile Telecommunication System) according to the wireless load situation of a cell and the requested service access priority. Control Method. According to the situation of different service loads in the cell load, the method can flexibly adjust the cell load service according to the strategy of giving low priority service to the high priority service, and can adjust the access service. The transmission rate maximizes the number of high-priority and real-time services in the cell and meets the system requirements. Background technique

In the third-generation mobile communication system UMTS, the network planning no longer involves the problem of channel allocation. However, because of the "soft capacity" in WCDMA (Wideband Code Division Multiple Access) systems, the problem has changed. It's very complicated.

In fact, a WCDMA system is an interference-limited system, and its cell capacity cannot be reflected by the number of call connections at all. Whether a call can be accessed is determined based on whether all existing calls in the cell can maintain the required signal-to-noise ratio (SIR) after accessing the call. The SIR value is the ratio of the received power to the interference level. It is closely related to the power control mechanism and the distance between the calling user and the base station. Because the transmission power of each base station is limited, the closer the calling user is to the base station, the smaller the transmission power required by the base station, and the greater the number of accessible users. The power control used in UMTS enables the receiver to obtain appropriate performance indicators by adjusting the SIR, such as the block error rate (BLER) and bit error rate (BER). The greater the change in received power, the higher the target SIR value needs to be. So can Whether or not to access an access request is closely related to the load status of the current cell and the service type of the access request itself (requiring different power and SIR levels to maintain the amount of shield required by the service).

When accessing an access request, there are two situations:

1. The request is accessed normally, and other users in the cell return to a balanced state under power control due to interference changes;

2. The service is accessed incorrectly, and some users in the cell lose calls due to interference changes that cannot return to a balanced state under power control. Mainly because the interference level is too high and the transmission power is limited, the SIR cannot reach the minimum SIR level required by some services.

In an ideal situation, the wireless access control method is only accessed when the calling user can access normally and other users can reach a balanced state. However, this ideal situation is possible only if accurate information is obtained for all calling users' propagation channels. A more practical method is to decide whether to access the calling user based on some information obtained in the cell.

At present, wireless access control basically adopts the following methods.

-Interactive access control method: This method is also an ideal access control method. In this method, call users request access first, and test whether the SIR of all users can reach a balanced state to decide whether to access the call request. This method is not applicable in real-time systems, because it will encounter severe convergence problems when testing whether the user reaches an equilibrium state, and it is impossible to evaluate the convergence of non-real-time users.

• Power-based access control method: This method controls the access of calling users based on the relationship between capacity and power limitation in a CDMA system. In the case of downlink, the transmission power of the base station is limited, and the access control method will determine whether to access the call based on whether the required transmission power of the call will cause the transmission power of the base station to exceed the total transmission power limit.

• Interference-based access control method: To avoid manual intervention during uplink access control The machine frequently reports the power level to the base station, and the base station can evaluate the current cell load by measuring the current interference level, and determine whether the call should be accessed based on the level of noise caused by the user accessing the call.

-Access control method based on call connection: This method converts the average capacity of a cell into the number of accessible call connections, which is very simple to implement. But in

In the WCDMA system, due to the relationship of "soft capacity", this method has low efficiency and poor practicability.

In UMTS, the interference-based access control method of the access control methods discussed above is generally used in the uplink, and the power-based access control method is used in the downlink. The access control method separately evaluates the increase in load caused by access to new calls or changes in wireless access bearers on the uplink and downlink. The new access request can be granted access only when the uplink and downlink access criteria are met at the same time.

The flowchart of the traditional wireless access control method is shown in Figure 1. When a new call request, a handover request, or a transmission channel change is received on the carrier frequency C1, the flow advances from step SP101 to step SP102.

In step SP102, the wireless access control method detects whether there is an overload warning, and if there is a wireless overload warning, the processing flow proceeds to step SP108, the new request is rejected, and the process ends.

If it is determined in step SP102 that there is no wireless overload warning, then in step SP103, it is detected whether the uplink interference exceeds the threshold after accessing the request, and it is determined whether to receive an uplink service request. If it is determined that the uplink service request cannot be received, the processing flow proceeds to step SP108, the new request is rejected, and the processing ends.

If it is determined in step SP103 that the uplink interference does not exceed the threshold after accessing the request, then in step SP104, it is detected whether the downlink transmission power is greater than the total transmission power, and it is determined whether to receive a downlink real-time service request. If it is determined that the downlink real-time service request cannot be received, the processing flow proceeds to step SP108, the new request is rejected, and the process ends. If it is determined in step SP104 that the downlink transmission power is not greater than the total transmission power, then in step SP105, the base station hardware resources are detected to determine whether the base station hardware is overloaded. If the base station hardware is already overloaded, the processing flow proceeds to step SP108, the new request is rejected and the processing ends.

If it is determined in step SP105 that the hardware resources of the base station are sufficient, then the channel code resources are detected in step SP106 to determine whether there is a channel code allocation. If no channel code can be assigned to the new access request, the processing flow proceeds to step SP108, the new request is rejected and the process ends.

If it is determined in step SP106 that a channel code can be allocated for the new access request, the processing flow proceeds to step SP107. In step SP107, after all the above tests are passed, the request is accessed.

However, such conventional access methods currently cannot fully meet the requirements of wireless access control in UMTS. They treat users of different priorities equally, and there is no flexible load adjustment strategy after overload. Summary of the invention

Considering the characteristics of multi-service users and multi-priority service access of the UMTS system, the present invention proposes a wireless access control method based on multi-service, multi-priority, and rate negotiation in UMTS.

According to the present invention, a wireless access control method based on multi-service, multi-priority, and transmission rate negotiation in a UMTS system is provided, which is characterized by including the following steps: a) Setting a new access request according to the QoS of a multi-service request Priority); b) calculating the total load of all services including the new access request; c) detecting whether there is a wireless overload warning in the cell according to the total load calculated in step b); d) if If a wireless overload warning is detected in step c), the transmission rate of services having a lower priority than the new access request priority is reduced to reduce the total load level, and the process returns to step b); e) If in step c) No wireless overload warning is detected, then access the new access Request.

The wireless overload warning is determined by the load control unit as a "pre-overload" state and a "overload," state according to the current load state and the capacity of the cell. If the wireless overload warning detected in step d) is the "overload" state, Then the new access request is not accessed.

According to the radio access control method of the present invention, in the case of different service loads in the root cell load, in the case of the cell radio load overload, the cell load service is flexibly adjusted according to the strategy of giving low priority service to high priority service And can adjust the transmission rate of access services, maximize the number of high-priority and real-time services in the cell, so as to meet the system requirements. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a flowchart of a conventional wireless access control method; and

FIG. 2 shows a flowchart of a wireless access control method based on multi-service, multi-priority, and transmission rate negotiation in a UMTS system according to the present invention. detailed description

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

In the present invention, according to the ^{3GPP (3 rd Generation partnership project)} QoS (Quality of Service, QoS) classification, all users will be classified according to their priority, and the user access according to the priority, congestion in the access In this case, reasonable rate negotiation is performed to maximize high-priority users.

The basic idea of the present invention is that high-priority users enjoy higher rights than low-priority users when accessing, and low-priority users are willing to sacrifice (reduce) their own access data transmission rate to reduce when congested Load level, allowing high-priority users to access. If the low-priority users do not have real-time QoS requirements, when the congestion reaches a certain level, the low-priority users may even be suspended, so that the priorities are high and real The number of time-sensitive access users reaches the maximum. When the load on the cell is reduced, users with low priority and low real-time requirements will be allowed to retransmit data and gradually increase their rate to reach the requested maximum transmission rate.

Table 1 shows the priorities defined according to the QoS classification of different service users. Priority defined by QoS classification

It is worth noting that category 3 can be further subdivided into n categories according to the "Traffic handling priority" in the RAB (radio access bearer) attribute.

The wireless access control method according to the present invention will be described in detail below based on the above classifications with reference to the drawings. FIG. 2 shows a flowchart of a wireless access control method based on multi-service, multi-priority, and transmission rate negotiation in a UMTS system according to the present invention.

As shown in FIG. 2, in step SP1, when a new call request, a handover request, or a transmission channel change is received on the carrier frequency C1, the user request priority class is set to Q according to the RAB attribute according to the classification in Table 1. If the service is a composite service (multiple service combinations), its access priority is set according to the lowest priority service in the composite service. For example, when the access service is "session + background", according to the "backstage" with the lower priority, the service is set to Q = 4. Next, perform the initial setting P-4, i = 3. Among them, P represents the lowest allowed priority service level, and i represents the adjustable transmission rate level of the service is 3. For "data stream" and "interactive" users, the adjustable transmission rates are 128kps, 64kbps, 28.8kbps, and 384kbps, 128kbps, 64kbps. The minimum transmission rates are 28.8kbps and 64kbps. In the Qos classification in Table 1, the priorities x = 1 and 2 are real-time services, and a minimum guaranteed transmission rate (Guaranteed bit rate) is required. Therefore, although the priority of x = l services is greater than that of x = 2 services, when wireless services are overloaded and Q = l services request access, priority x = 2 services will at most reduce the transmission rate to a minimum guarantee. Transmission rate, and non-real-time services such as priority x = 3 or x = 4 may be suspended or released.

Then, in step SP2, the total load of the uplink and downlink with priorities from 1 to P in the current cell is calculated according to the formula described below, and all services with a priority greater than P are suspended or released during overload. For the calculation of the total uplink and downlink load, for example, the uplink is calculated based on uplink interference, and the downlink is calculated based on transmit power. Chapter 9 of "WCDMA for UMTS" by Harri Holma, and Antti Toskala, published by John Wiley & Sons in 2001 The detailed description is omitted here.

Lm ^ p and L _DL , _P are all uplink and downlink service loads with priority p, and L _UL and L _DL are the total uplink and downlink load of the cell.

Next, in step SP3, it is detected whether the current cell has an overload warning from the "Load Control (LC)" unit. If an overload warning occurs in the uplink and downlink, it enters the priority-based transmission rate negotiation section (step SP4 ~ SP5, SP51 ~ 54 and SP20), if no overload warning appears, then enter the normal access load detection section (steps SP6, SP71-SP72, SP81-SP85, SP9, and SP11-SP14).

These two cases are described separately below.

First, if an overload warning is detected in step SP3, the state of wireless overload is detected in step SP4.

There are two states of wireless overload, the "pre-overload" state and the "overload" state, which are determined by the "load control (LC)" unit according to the current load state and the capacity of the cell.

If it is determined in step SP4 that the "overload" state appears, it indicates that the cell is overloaded and is not suitable for accessing any requests. The cell load is adjusted by the "Load Control (LC)" to return to the normal state. At this time, processing The flow advances to step SP20, rejects the new request and ends the entire flow.

In step SP4, when the "pre-overload" status appears, it indicates that the cell load may be overloaded at this time, and can be adjusted according to the priority of the access request, allowing high-priority service access and preventing low-priority user access. At this time, the processing flow proceeds to step SP5.

In step SP5, if the access request priority Q = 4 is determined, indicating that the access request has the lowest priority, the processing flow proceeds to step SP20, and the request is rejected and the entire flow is ended.

If it is determined in step SP5 that the access request priority Q is not equal to 4, the processing flow proceeds to step SP51.

In step SP51, it is determined whether the priority of the access request is 4> Q≥3. If it is determined that the priority of the access request is 4> Q≥3, the service request is an "interaction" type service, and the processing flow proceeds to step SP53. If it is determined in step SP51 that the access request priority Q <3, the service is a real-time service with a higher priority, and the processing flow proceeds to step SP52.

In step SP53, after determining the priority of the access request 4> Q≥3, Services in the zone that are currently in the access state and have a priority lower than Q are suspended or rejected, while services with priority x = Q in the cell are "rate-negotiated", that is, service loads with the same priority x = Q are transmitted The rate Rj is simultaneously reduced to the next level

For example, the access user's service priority is Q = 3.1. When overloaded, the transmission rate of all services with x = 3.1 can be gradually reduced from R ₃ = 384 kbps to ¾ = 321Λρ8, and higher priority users are not affected.

Then, the processing flow proceeds to step SP54, where it is determined whether after the "rate negotiation" whether the service load transmission rate Rj of the same priority x = Q can be guaranteed to be greater than its minimum transmission rate. If the service load transmission rate Rj of the same priority x = Q can be guaranteed to be greater than its minimum transmission rate, it indicates that it is possible to allow access to the new service request, and the process returns to step SP2. Otherwise, the processing flow proceeds to step SP20, the new business request is rejected and the entire flow ends.

In step SP52, after determining the access request priority Q <3, the service is a real-time service with a higher priority. At this time, in order to speed up the method adjustment speed, ensure the real-time requirements of the service and the minimum guaranteed transmission rate (Guaranteed bit rate) requirements, first suspend or #release non-real-time services such as priority x = 3 or x = 4. , And then gradually reduce the priority x = type 2 service transmission rate until the minimum guaranteed transmission rate.

Similarly, after this "rate negotiation", the processing flow proceeds to step SP54. In step SP54, it is determined whether the load transmission rate Rj of the priority x = type 2 service can be guaranteed to be greater than its minimum transmission rate. If it is possible to ensure that the load transmission rate Rj of the class x = 2 services is greater than its minimum transmission rate, it indicates that it is possible to allow access to the new service request, and the process returns to step SP2.

When all the priority x = 2 service transmission rates of the cell are adjusted to the minimum guaranteed transmission rate, and the cell is still in an overloaded state, the processing flow proceeds to step S20, and the service request will be rejected and the entire process will be ended.

When the transmission rate is reduced to a certain level and the cell load is no longer in an overloaded state, the priority service can be accessed and then enter the normal access load check 测部分。 Test section.

The following describes the normal load access detection when it is determined that there is no wireless overload warning in the cell

If it is determined in step SP3 that the cell has no overload warning, it indicates that the current cell is in a normal load state. The processing flow proceeds to step SP6.

When the cell is in a normal load state, it is necessary to check whether the cell can still maintain a normal load balancing state after the access service request. Whether the new load is connected depends on the type of load. The real-time service and non-real-time service have different measurement standards and methods. If the service is a composite service (multiple service combinations), both real-time and non-real-time are checked. Only when all composite services pass the check can they be accessed.

First, in step SP6, it is determined whether the type of the RAB is a real-time load type or a non-real-time load type. If it is a real-time load type, the processing flow proceeds to step SF71. If it is a non-real-time load type, the processing flow proceeds to step SP72. The following specifically describes these two business situations.

For the real-time service, in step SP71, according to the load condition of each carrier frequency and the service classification situation, and the specific requirements of the operator, search and select the appropriate carrier frequency Cm. For example, a new service request can be connected to a lightly loaded cell according to the "balance load" algorithm. According to the "service classification" algorithm, services with higher transmission rate requirements and services with lower transmission rate requirements can be respectively connected to cells with different carrier frequencies.

Then, in step SP81, the uplink load of the newly requested real-time service is checked to determine whether to receive an uplink real-time service request. If the uplink traffic exceeds the load threshold at this time, the processing flow proceeds to step SP85, the request is rejected and the entire flow ends.

If it is determined in step SP81 that the uplink real-time service request can be received, the processing flow proceeds to step SP83. In step SP83, the downlink load of the newly requested real-time service is checked to determine whether a downlink real-time service request is received. If the downlink service exceeds the load threshold at this time, the processing flow proceeds to step SP85, the request is rejected and the entire flow is ended. If it is determined in step SP83 that the downlink real-time service request can be received, the processing flow proceeds to step SP9.

Similarly, for non-real-time services, in step SP72, according to the load conditions and service classification conditions of each carrier frequency, and the specific requirements of the operator, search and select the appropriate carrier frequency Cm. For example, a new service request can be connected to a lightly loaded cell according to the "balance load" algorithm. According to the "service classification" algorithm, services with higher transmission rate requirements and services with lower transmission rate requirements can be respectively connected to cells with different carrier frequencies.

Then, in step SP82, the uplink load of the newly requested non-real-time service is checked to determine whether to receive an uplink non-real-time service request. If the uplink service exceeds the load threshold at this time, the processing flow proceeds to step SP85, the request is rejected and the entire process is ended.

If it is determined in step SP82 that the uplink non-real-time service request can be received, the processing flow proceeds to step SP84. In step SP84, the downlink load of the newly requested non-real-time service is checked to determine whether a downlink non-real-time service request is received. If the downlink traffic exceeds the load threshold at this time, the processing flow proceeds to step SP85, the request is rejected and the entire flow ends.

If it is determined in step SP84 that the downlink non-real-time service request can be received, the processing flow proceeds to step SP9.

It should be noted that in the above processing, it is necessary to separately check the uplink and downlink loads of newly requested real-time services and non-real-time services according to the classification of services. In the case of a composite service (multiple service combinations), all services in the composite service must be checked. If the uplink or downlink service of any of these services exceeds the load threshold, the request is rejected and the entire process ends.

When all wireless resources have passed the check, that is, access to a new service request is permitted, in step SP9, it is detected whether the hardware resources of the base station meet the requirements for accessing the request. If the hardware resources of the base station cannot meet the demand for accessing the new request, Go to step SP20, reject the request and end the whole process.

If it is determined in step SP9 that the hardware resources of the base station can meet the requirements for accessing the new request, then it is checked in step SP11 whether there is an excess channel code allocation in the cell. If there is no extra channel code assigned to the new request, the processing flow proceeds to step SP20, the request is rejected, and the entire flow ends.

If it is determined in step SP11 whether there is an excess channel code in the cell assigned to the new request, then it is determined in step SP12 whether Cm is equal to Cl. If Cm = Cl, the request is accessed on the C1 carrier frequency in step SP14; if Cm ≠ Cl, the request is accessed in step SP13, and a hard handover is initiated to the carrier frequency Cm.

As can be seen from the above description, the wireless access control method disclosed in the present invention for performing load adjustment and rate negotiation according to the wireless load situation of the cell and the requested service access priority in the third generation (3G) mobile communication system UMTS. According to the situation of different service loads in the cell load, and under the condition that the wireless load of the cell is overloaded, the cell load service can be flexibly adjusted according to the strategy of giving priority to low priority services to high priority services, and the access service can be adjusted. Transmission rate, thereby maximizing the number of high-priority and real-time services in the cell and meeting the requirements of the system.

Although the present invention has been described above according to a preferred embodiment, the present invention can be further modified within the spirit and scope of the present disclosure. Accordingly, this application covers any variations, uses, or adaptations of the invention by its general principles. Additionally, this application is intended to cover known or commercial practice that is technically related to the invention and is within the scope of the appended claims, starting from this disclosure.

Claims

1. A wireless access control method based on multi-service, multi-priority and transmission rate negotiation in a UMTS system, comprising the following steps:

a) Set the priority of the new access request according to the QoS of the requested multi-service; b) Calculate the total load of all services including the new access request; c) Detect based on the total load calculated in step b) Whether there is wireless overload warning in the cell;

d) if a wireless overload warning is detected in step c), then reduce the transmission rate of services with a priority lower than the priority of the new access request to reduce the total load level, and return to step b);

e) If no wireless overload warning is detected in step c), access the new access request.

2. The wireless access control method according to claim 1, wherein, in step c), the wireless overload warning is determined by the load control unit as the "pre-overload" state and the "overload" according to the current load state and the capacity of the cell. "Status, and if the wireless overload warning detected in step d) is" overload "status, the new access request is not accessed.

3. The wireless access control method according to claim 1 or 2, further comprising the following steps:

f) checking whether the cell can still maintain a normal load balancing state after accessing the new access request, and if the normal load balancing state cannot be maintained, rejecting the new access request;

g) when access to the new access request is allowed in step f), detecting whether the hardware resources of the base station meet the requirements for accessing the new access request; if the hardware resources of the base station cannot meet the access to the new access request The new access request is rejected; h) if it is determined in step _g ) that the hardware resources of the base station can satisfy the access to the new access request; If there is an access request requirement, check whether the cell has an excess channel code allocation, and if there is no excess channel code allocation, reject the new access request;

i) After passing the channel code allocation check, if Cm = Cl, access the new access request on the C1 carrier frequency; if Cm ≠ Cl, access the new access request and initiate to the carrier frequency Cm Hard handover.

4. The wireless access control method according to claim 3, wherein in step f), if the new access request is a composite service, both real-time and non-real-time are checked, and only when All composite services can be accessed only after passing the new access request.

5. The wireless access control method according to claim 4, characterized in that, according to the "balance load" algorithm, the new access request is accessed to a cell with a lighter load.

6. The wireless access control method according to claim 4, characterized in that, according to a "service classification" algorithm, a service with a higher transmission rate requirement and a service with a lower transmission rate requirement in the new access request are respectively separated. Access to cells with different carrier frequencies.

7. The wireless access control method according to any one of claims 4 to 6, wherein the priority of the new access request is defined according to the QoS classification shown in the following table:

8. The radio access control method according to claim 7, further comprising subdividing category 3 according to a service processing level in a radio access bearer RAB attribute. Priority.

9. The wireless access control method according to claim 7 or 8, characterized in that, in a "pre-overload" state, if the new access request priority Q = 4, it indicates that the new access request is The lowest priority, the new access request is immediately rejected.

10. The wireless access control method according to claim 7 or 8, characterized in that, if the priority of the new access request is 4> Q≥3, the access status in the cell is currently low and the priority is low Services on Q are suspended or rejected, and "rate negotiation" is performed on services of priority x = Q in the cell, and the service load transmission rate Rj of the same priority x = Q is reduced to the next level at the same time

At this time, if the transmission rate Rj of the service load with the same priority x = Q can be guaranteed to be greater than its minimum transmission rate, access to the new access request is allowed; otherwise, the new access request is rejected.

11. The wireless access control method according to claim 7 or 8, characterized in that if the new access request priority Q <3, the priority is x = 3 or x = 4 type of non-real-time service Suspend or release, and then gradually reduce the priority x = type 2 service transmission rate until the minimum guaranteed transmission rate. At this time, if the load transmission rate Rj of the priority x = type 2 service can be guaranteed to be greater than its minimum transmission rate, then allow Access the new access request; if all the priority x = 2 service transmission rates of the cell are adjusted to the minimum guaranteed transmission rate, the cell is still in an overload state, then the new access request is rejected.