WO2010075638A1

WO2010075638A1 - Method for resource allocation in a communication system

Info

Publication number: WO2010075638A1
Application number: PCT/CN2008/002144
Authority: WO
Inventors: Shuguang Yang; Lin Dong; Rui Tian
Original assignee: Telefonaktiebolaget L M Ericsson (Publ)
Priority date: 2008-12-31
Filing date: 2008-12-31
Publication date: 2010-07-08
Also published as: CN102273297A

Abstract

The present invention provides a method for resource sharing among different transport resources, comprising the steps of: RNC (101) selecting related preferred transport type, RNC (101) determining availability status of the preferred transport resource, RNC (101) determining utilization status of the preferred transport resource in low load state, and RNC (101) setting up a new transport bearer on the preferred transport resource. With this invention, the overall utilization rate of transport resource can increase and the congestion and overload of specific transport resources can be avoided.

Description

Method for Resource Allocation in a Communication System

TECHNICAL FIELD

This invention relates to telecommunication technology and, more particularly, to a method for resource sharing among different transport resources in UTRAN.

BACKGROUND OF THE INVENTION

Nowadays, there are more and more transport resources introduced into UTRAN (UMTS Terrestrial Radio Access Network), for example, ATM transport and IP transport. With its own specific advantages, IP transport technology is acting as a UTRAN transport solution gradually and will be an alternative to ATM transport technology. Due to current predominant position of ATM transport network and migration issues from ATM transport network to IP transport network, multiple transport technologies will still coexist and interwork in radio access network for a long time. It's necessary to find some ways to assure that UTRAN nodes can communicate with each other which have ATM or IP over different interfaces such as Iu, Iub, Iur interfaces etc in UTRAN networks.

RNC (Radio Network Controller) is required to support dual stack of transport technology (ATM and IP) over Iub interface, so as to support multiple transport resources in UMTS. RBS (Radio Base Station) supports either ATM or IP transport resource or both of them due to different requirement of user service and migration impacts. It's necessary and important that the two transport technologies can coexist and interwork well.

Currently, there're mainly two solutions about interworking between different transport resources. On Iub interface, assume RNC supports dual stack of transport technology (ATM and IP). RNC 101 connects with different kinds of RBS 102 directly as shown in Figure 1.

Under this condition, RNCs 101 have to set up new transport bearers based on the same type of transport resource as that supported by RBS 102. For example, if RBS 102 only supports ATM transport resource, only the ATM transport resources on RNC 101 side are used for new transport bearer establishment over Iub interface. Even RBS 102 also supports dual stack of transport resource (such as ATM and IP), RNC 101 can only set up transport bearer on two type of transport resource respectively where it should be same on both sides. The usages of two different kinds of transport resources are independent.

In order to resolve this issue of communication between different kinds of transport technologies, a new equipment is provided in 3GPP TR 25.933 V5.4.0 and Ericsson patent (patent number: US 2001/0053145 Al). This new equipment named as interworking unit (IWU) 103 is defined to implement the transform between different transport technologies as shown in Figure 2. RNC 101 can set up new transport bearers based on different transport resource with that supported in RBS 102 by IWU 103.

For example, RNC 101 has free ATM transport resource on Iub interface. Peer RBS 102 node only supports IP transport technology. When RNC 101 establishes a new transport for user plane transmission, RNC 101 sends ATM transmission address and bind ID with Alcap protocol to IWU 103. When IWU 103 receives the request of transport bearer set up, IWU 103 selects out the corresponding IP address of RBS 102 and sets up transport bearer with RBS 102 by IP Alcap protocol. By this interworking equipment, a transport bearer can be set up successfully between RNC 101 and RBS 102.

This basic procedure is shown in Figure 3. Here, assume that RNC 101 supports dual stack of transport and only ATM transport resource available. RBS 102 only supports IP transport.

However, the transport resource usage in RNC 101 is still irrelevant. This causes unbalanced utilization among different transport resources. In more serious scenarios, one kind of transport resource is highly used even exhausted while another kind of transport resource is extremely free. Thus, a big waste of transport resources may occur due to invalid transport resource usage.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a method for allocating transport resources in a radio communication network with high resource utilization rate.

It is a further object of the present invention to provide a radio communication network in which the resource utilization rate is high.

According to one aspect of this invention, the present invention provides a method, comprising a first steps of receiving a request for setting up a transport bearer corresponding to a transport service type, the transport service type being associated with one of the transport resources. If the associated transport resource is in a low load state, the transport bearer is set up on the associated transport resources. If the associated transport resource is not in a low load state and any of the other transport resources is in a low load state, the transport bearer is set up on the any of the other transport resources. If neither of the cases above occur, the request is rejected.

According to another aspect of this invention, the present invention provides a radio communication network, comprising a plurality of radio base stations, and a radio network controller communicating to the plurality of radio base stations. wherein the radio network controller is configured to allocate transport resources in the following steps. First, a request for setting up a transport bearer corresponding to a transport service type is received from one of the plurality of radio base stations , the transport service type being associated with one of transport resources. Then, if the associated transport resource is in a low load state, the transport bearer is set up on the associated transport resources. If the associated transport resource is not in a low load state and any of the other transport resources is in a low load state, the transport bearer is set up on the any of the other transport resources. If neither of the cases above occur , the request is rejected.

With this invention, it is possible to enable resource sharing between different transport resources and increase the overall utilization rate of transport resource and avoid the congestion and overload of specific transport resources.

This invention also provides a redundancy mechanism among different transport resource .When one kind of transport resource are unavailable in some abnormal condition, the new service can be established on other available transport resource to secure the network accessibility and stability, robustness.

In this invention, the dual threshold of method ensures the accuracy and reliability of utilization status estimation for transport resources.

The strategy of different level of threshold basis on different types of service provides a flexible way for resource sharing between various types of users and increases utilization of transport resource.

BRIEF DESCRIPTION OF THE DRAWINGS

Features as well as advantages of the present invention will become to be more apparent to those skilled in the art from the following detailed description of the preferred embodiments when taking reference to the accompanying figures.

In these figures:

FIG 1 illustrates an solution for interworking between different transport resources according to the prior art;

FIG 2 illustrates another solution for interworking between different transport resources according to the prior art;

FIG 3 illustrates the basic procedure in the interworking according to an existing solution;

FIG 4 illustrates the architecture for resource sharing among different transport resources;

FIG 5 illustrates the main flow chart for resource sharing among different transport resources;

FIG 6 illustrates the relationship between time and the utilization rate of bandwidth or throughput;

FIG 7 illustrates an exemplary procedure of the dual threshold method;

FIG 8 illustrates the different levels for different priorities for different service users;

FIG 9 illustrates an exemplary procedure of the multi-level protective threshold method.

DETAILED DESCRIPTION OF THE INVENTION

It should be noted that the present invention is described in the no limiting, example context of a universal mobile telecommunication systems (UMTS). The following example will describe transport resource interworking between RNC 101 and RBS 102 in Iub interface.

As shown in Figure 4, in a radio access network of UMTS, assume that RNC 101 supports dual stack (such as ATM/IP) of transport technologies. RNC 101 is connected with different types of RBSs 102 over Iub interface. Some RBSs 102 support IP transport. Some RBSs 102 still support ATM transport. The others support both IP and ATM transport over Iub. The transport resource between RNC 101 and IWU 103 are seen as a resource pool 104 and able to share each other based on the specific method of current invention.

Different service has its preferred transport resource based on its specific quality of service (Qos) and bandwidth utilization requirements. For example, data service is preferred transporting on IP transport resource, while AMR (Adaptive Multi-Rate) service is preferred transporting on ATM transport resource due to sensitivity to transmission delay etc. This relationship between different service and transport resources can be configured on RNC 101 by operators. In the present invention, such preference is always satisfied, if possible.

Figure 5 describes the main procedure of transport resource management between ATM and IP transport technologies in RNC 101. RNC 101 measures the utilization of transport resource in real time and stores related status information (such as user data throughput on IP based transport or utilization rate of physical bandwidth resource on ATM based transport).

When new request of transport bearer comes, RNC 101 will initiate the procedure of transport resource management. At step S501, when a new transport bearer (such as for user plane of R99 PS data RAB) setup request comes, RNC 101 selects related preferred transport type according to configured relationship between service type and transport resource.

At step S502, RNC 101 checks utilization status of the preferred transport resource, if it is in low (normal) load state, then at step S503, the new transport bearer is set up on the preferred transport resource.

If at step S502, RNC 101 determines the preferred IP transport resource in high load state, then, at step 504, RNC 101 checks utilization status of the unpreferred transport resource, if it is in low load state, the new transport bearer will be set up on the unpreferred ATM transport resource. Otherwise, RNC 101 rejects the request of new transport bearer (step S506). At step 502, preferably, RNC 101 checks availability status of the transport resource before checking utilization status.

This method allows for different transport resource to share each other when one transport resource is unavailable or on highly loaded condition. This can ensure a good utilization rate of transport resource and keep a balance among different transport resources.

In above main procedure, the estimation of utilization status of transport resource and resource sharing are two key parts. The accuracy of estimation of utilization status is a prerequisite of resource adjustment.

Hereafter, two methods are introduced into the estimation of utilization status for transport resources and resource management. The first one is dual threshold detection and hysteresis timer strategy. This method is to ensure that accuracy of estimation and avoid erroneous decision from jitters of transport resource.

The other new method sets multi-level protective threshold of transport resource admission for different types of service users. This method can ensure flexible utilization and management between different transport resources and good quality of service for various users.

In the dual threshold method, dual thresholds (High Thr and Low Thr) and a hysteresis timer are configured by operators. Here the load during measurement is for physical bandwidth on ATM transport or average throughput on IP transport, as shown in Figure 6.

The main procedure of the dual threshold method is shown in Figure 7.

At step S701, RNC 101 resides in normal load state of transport resource usage and flag (Load_status_flag) is 0. RNC 101 monitors utilization status on current transport resource. At step S702, RNC 101 checks current average measured utilization rate, if it is more than high threshold (High_Thr), then, at step S703, RNC 101 checks duration under high threshold, if it is longer than hysteresis timer of time, then, at step S704, RNC 101 determines that transport resource in high load state and sets flag (Load_status_flag) as 1.

Then, at step S705, RNC 101 checks current average measured utilization rate, if it is less than low threshold (Low_Thr), then at step S706, RNC 101 checks duration under high threshold, if it is longer than and hysteresis timer of time, then RNC 101 decides the transport resource to return normal load state and sets flag (Load status flag) as 0 from 1. Or, if it is determined current average measured utilization rate is not more than high threshold (High_Thr) (at step S702), or duration under high threshold is not longer than hysteresis timer of time (at step S703), then the process goes back to step S701.

The thresholds and hysteresis timer also can be adjusted dynamically based on specific methods. Furthermore, the method about accumulation and smoothing of multiple samples can be adopted and have better effect on estimation of utilization status.

This method of dual threshold and hysteresis timer can monitor the trend of transport resource utilization and make accurate decision on utilization status of resource usage. This assures a correct precondition for following resource adjustment.

For the burst characteristics of packet data traffic, the fluctuation of its corresponding transport resource is more obvious and intense. Thus, it's recommended that this method is used to monitor utilization status on date service user preferred IP transport resource.

The other method provided by the present invention for the estimation of utilization status for transport resources and resource management defines multiple protective threshold of resource utilization and implements different access priorities of different service users during load sharing among different transport resource.

In this method, admission priorities of transport resource are configured for different service types of users in system by operators based on the type of preferred transport resource and Qos requirements of service.

In below example, assume preferred transport resource for AMR users is ATM bandwidth. Accordingly, the priority of service types is set as below: high priority for incoming AMR users (such as Handover users), medium priority for incoming data users and local AMR users, and low priority for other users.

Different admission thresholds for transport resource are also defined based on different types of users' priority to ensure high transport resource utilization rate and good performance of overall system. Accordingly, three thresholds are defined in Figure 8.

Figure 9 shows the main procedure of resource allocation for users basis when a new transport bearer request comes.

At step S901 , when new transport bearer (such as a transport bearer of data user) request comes, RNC 101 will record service type of this new transport bearer and check current the utilization status of allocated ATM bandwidth resource. At step S902, RNC 101 checks utilization rate of bandwidth, if, including the new needed transport resource, it is not less than threshold 1, which means utilization rate of transport resource is in high load state, RNC 101 will reject the request of this transport bearer (at step S907). If, at step S902, RNC 101 determines utilization rate of bandwidth including the new needed transport resource is less than thresholdl, then at step S903, RNC 101 checks whether the quest is from incoming AMR users, if not, then, at step S904, RNC 101 checks whether the request is from incoming data users or local AMR users while the utilization rate of bandwidth is less than threshold2, if not, at step S905, RNC 101 checks whether the utilization rate of bandwidth is less than threshold3, if not, then at step S907, the current transport bearer request is rejected..

If, at step S903, S904, or S905, the result of judgment is "yes", then at step S906, RNC 101 allocates free transport resource for new transport bearer.

When multiple new users (such as one AMR user and one data user) access simultaneously, RNC 101 will adopt same method as above single user independently firstly. When the free transport resource is enough only for one user, the preferred user will have higher priority to be allocated the free transport resources. For example, here, the free ATM transport resource will be allocated to its preferred AMR service user and data service user will be put in queues and waiting for free resource.

Another scenario is when a data service user access with high data rate, if the current free preferred and unpreferred transport resource can meet with its requirements of bandwidth. Then RNC 101 can consider to downswitch the data service user to lower data rate, then check if free transport resource is enough for this user according to above method for single user as Figure 9.

On this example, this method is used in the process of service users admission. Meanwhile, during service users holding, the transport resource will vary with the resource release and reallocation. RNC 101 will monitor utilization of all transport resources simultaneously and keep track of fluctuation of load for transport resource. Based on this knowledge, it will adjust different service users to their preferred transport resources dynamically and keep balance of utilization for different transport resource on the whole.

The method of dual thresholds provides a reliable way of estimation for transport resource utilization. The method of multi-level protective threshold gives a strategy on transport resource share based on service user priorities configured by operators. Both together can implement transport resource sharing between different types of transport resource in RNC 101 and IWU 103.

The embodiments of the invention described above are intended to be exemplary only. Those skilled in the art may understand that the provided embodiments can be further varied in many aspects. The scope of the invention is therefore intended to be limited solely by the scope of the appended claims.

Claims

We claim:

1. A method for allocating transport resources in a radio communication node, comprising the steps of: receiving a request for setting up a transport bearer corresponding to a transport service type, the transport service type being associated with one of the transport resources(S501); if the associated transport resource is in a low load state(S502), setting up the transport bearer on the associated transport resources(S503), if the associated transport resource is not in a low load state and any of the other transport resources is in a low load state(S504), setting up the transport bearer on the any of the other transport resources(S505), otherwise, rejecting the request.

2. The method of claim 1, wherein the transport resources comprise bandwidth or throughput of a channel.

3. The method of claim 2, wherein when the average measured utilization rate of the bandwidth is less than a threshold for a duration longer than a predetermined time interval, the associated transport resource is considered as being in the low load state.

4. The method of claim 2, wherein a plurality of users are assigned to thresholds respectively and for each of the users, when the average measured utilization rate of the bandwidth is less than the assigned threshold for a duration longer than a predetermined time interval, the associated transport resource is considered as being in the low load state.

5. The method of any one of claims 1-5, wherein the node is a radio network controller.

6. A radio communication network, comprising: a plurality of radio base stations (102); and a radio network controller (101) communicating to the plurality of radio base stations, wherein the radio network controller (101) is configured to allocate transport resources in the following way: receive from one of the plurality of radio base stations (102) a request for setting up a transport bearer corresponding to a transport service type, the transport service type being associated with one of transport resources; and if the associated transport resource is in a low load state, setting up the transport bearer on the associated transport resources, if the associated transport resource is not in a low load state and any of the other transport resources is in a low load state, setting up the transport bearer on the any of the other transport resources, otherwise, rejecting the request.

7. The radio communications network of claim 6, wherein the transport resources comprise bandwidth or throughput of a channel.

8. The radio communications network of claim 7, wherein if the average measured utilization rate of the bandwidth is less than a threshold for a duration longer than a predetermined time interval, the associated transport resource is considered as being in the low load state.

9. The radio communications network of claim 7, wherein a plurality of users are assigned to thresholds respectively and for each of the users, if the average measured utilization rate of the bandwidth is less than the assigned threshold for a duration longer than a predetermined time interval, the associated transport resource is considered as being in the low load state.

10. An apparatus for allocating transport resources in a radio communication network, comprising: means for receiving a request for setting up a transport bearer corresponding to a transport service type, the transport service type being associated with one of the transport resources; means for setting up the transport bearer on the associated transport resources if the associated transport resource is in a low load state, or on the other transport resources if the associated transport resource is not in a low load state and the other transport resource is in a low load state.