CN100441047C - Method for Reducing Call Setup Time in Wideband Code Division Multiple Access System - Google Patents

Abstract

The invention discloses a method for reducing the call establishment time in a wideband code division multiple access system, comprising: UTRN triggers a user terminal to connect to an RNC, and the user terminal sends an RNC connection establishment request message to the RNC in the UTRN, and the message carries Initial direct transmission message: After receiving the RNC connection establishment request message, the RNC transparently transmits the non-access layer connection management service request message contained in the initial direct transmission message to the core network, and at the same time initiates the establishment process of UTRN access layer resources, In this way, the parallel execution of the non-access stratum and access stratum signaling is realized; when the RNC receives the non-access stratum signaling that needs to be downloaded, it judges whether the RNC connection has been established, and if it has been established, it directly downloads the non-access stratum signaling. Layer signaling, if not completed, cache the non-access layer signaling, and send the non-access layer signaling immediately after receiving the RNC connection establishment completion message. The present invention only needs to make minor changes to the existing process to realize the obvious reduction of call delay, and can be easily realized without increasing any hardware cost.

Description

Method for Reducing Call Setup Time in Wideband Code Division Multiple Access System

technical field

The present invention relates to the call establishment method in the 3rd generation mobile communication system, relate in particular to a kind of WCDMA (Wideband Code Division Multiple Access, wideband code division multiple access) method for reducing the call establishment time.

Background technique

The goal of ITU-T (ITU Telecommunication Commission) to develop the third generation mobile communication system is to unify the standard of IMT-2000. However, due to technical, commercial and political reasons, after years of selection and integration, five IMTs were finally established. -2000 Radio Transmission Technology (RTT, Radio Transmission Technology) specification, namely WCDMA, cdma2000, TD-SCDMA, UMC-136 and DECT, among which WCDMA, cdma2000 and TD-SCDMA based on CDMA technology have become the mainstream of the third generation mobile communication system Specifications for wireless transmission technology. WCDMA technology, as a commercially mature technology, has become the third-generation air interface widely adopted. WCDMA network will no longer be limited to voice and low-speed data services, but will also provide mobile data services such as videophone, high-speed Internet access, video streaming and online games.

While the WCDMA system provides a variety of wireless business services and wider wireless bandwidth, it also prolongs the call setup time due to the complexity of the signaling process. According to commercial network statistics, the average call setup time of the current WCDMA system is about 2 seconds longer than the average call setup time of the GSM system. Enduring a longer call setup time is undoubtedly unacceptable, and the long call setup time has become one of the main reasons restricting the large-scale application of WCDMA. 3GPP has recognized the seriousness of the call delay problem and set up a special working group to study it.

At present, there are patents for reducing call setup delay at home and abroad. For example, the U.S. patent entitled "Signaling transport over a bearer network for low latency services" with the application serial number 687319 filed on November 16, 2003 discloses a method for reducing call setup delay, which is useful for those who need For services with less call setup delay, apply for a dedicated bearer for signaling transmission to reduce call setup time. This method needs to apply for dedicated resources for transmission according to different signaling, and it is too complicated to implement. Another example is that the date of announcement is December 22, 2004, and the publication number is CN1557084 entitled "Reducing Call Setup Waiting Time by Encapsulating Signaling Messages", which discloses a method for reducing call setup delay, which uses CDMA2000 The short data burst feature of the system packs multiple messages into one message, and reduces the call establishment delay by reducing the number of air interface message interactions. This method can only be realized by utilizing the short data burst characteristic of CDMA2000 system, and it has no reference significance for other communication systems without this characteristic.

Contents of the invention

In view of the existing problems and deficiencies in the method for reducing call setup delay in the above-mentioned existing WCDMA system, the purpose of the present invention is to provide a wideband code division multiple access system with simple implementation, strong compatibility and significantly reduced call setup time. in the call setup method.

The present invention is achieved in that a method for reducing call setup time in a wideband code division multiple access system comprises the following steps:

(1) The terrestrial radio access network triggers the user terminal to perform a radio resource control connection, and the user terminal sends a radio resource control connection establishment request message to the radio network controller in the terrestrial radio access network, and the message carries initial direct message;

(2) After the radio network controller receives the radio resource control connection establishment request message, it transparently transmits the non-access layer connection management service request message contained in the initial direct transmission message to the core network, and simultaneously initiates the ground wireless The establishment process of access layer resources in the access network, so as to realize the parallel execution of non-access layer and access layer signaling;

(3) When the radio network controller receives the non-access stratum signaling that needs to be downloaded, it judges whether the radio resource control connection has been established, and if it has been established, directly downloads the non-access stratum signaling; if not After completion, the non-access stratum signaling is cached, and the non-access stratum signaling is issued immediately after receiving the radio resource control connection establishment completion message.

Preferably, for the radio resource control connection, the establishment process of the terrestrial radio access network access layer resources in the step (2) is specifically:

The radio network controller first sends a radio resource control connection establishment message to the user terminal according to the current network resources to establish air resources, and at the same time establishes a radio link, a bearer, and a frame protocol of the Iub port, so that air resources and Ground resources are built in parallel.

Preferably, for the Iu signaling connection, the establishment process of the terrestrial wireless access network access layer resources in the step (2) is specifically:

After receiving the radio access bearer assignment message sent by the core network, the radio network controller first sends a radio bearer establishment message to the user terminal to establish air resources; The establishment of resources between the core networks and the establishment of access layer resources in the terrestrial wireless access network enable parallel establishment of air resources and ground resources during the Iu signaling connection process.

According to the WCDMA system call establishment process stipulated in the 3GPP protocol, it can be known that it is divided into the access stratum (Access Stratum) establishment process and the non-access stratum (Non Access Stratum) establishment process, and the access stratum establishment process is divided into ground resources The establishment process and the establishment process of air resources. The present invention processes the access layer signaling and the non-access layer signaling in parallel, and at the same time establishes ground resources and air resources in the access layer in parallel, and the implementation of the parallel mode greatly reduces the time spent on the entire call , the invention can effectively reduce the call setup time by more than 1 second. The present invention only needs to make minor changes to the existing process to realize the obvious reduction of call delay, and can be easily realized without increasing any hardware cost.

Description of drawings

FIG. 1 is a schematic diagram of a call signaling flow in an existing WCDMA system;

Fig. 2 is a schematic diagram of a call signaling flow in the present invention.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings.

WCDMA system consists of three parts: core network (CN), terrestrial radio access network (UTRAN) and mobile terminal (UE). Among them, UTRAN is composed of one or more radio network subsystems (RNS). An RNS consists of a Radio Network Controller (RNC) and one or more Node Bs. An RNC can be connected to another RNC through an Iur interface. RNC and Node B are connected through Iub interface. The CN handles switching and routing of calls and data connections to and from external networks. UTRAN handles all radio access related functions. UE is the interface with the user. The interface between CN and UTRAN is called Iu interface, and the interface between UTRAN and UE is called Uu interface.

As shown in Fig. 1, the call signaling of the existing WCDMA system is divided into the access layer process and the non-access layer (high-layer protocol module irrelevant to wireless access) process according to the 3GPP protocol. The access layer process is further divided into the establishment process of air resources (signaling related to Uu interface) and the establishment process of ground resources (signaling related to Iu interface and Iub interface). The WCDMA system call flow essentially includes two parts: RRC connection and Iu signaling connection. The RRC connection is a two-way point-to-point connection established between the UE and the RRC protocol layer of the UTRAN, that is, a signaling path is established between the UE and the UTRAN to realize the allocation of radio resources. For a UE, there is at most one RRC connection, which is established at the beginning of the call establishment, released after the call ends, and maintained during the period. The Iu signaling connection establishes a signaling path between the UE and the CN, and mainly transmits non-access stratum signaling between the UE and the CN. In UTRAN, non-access stratum signaling is transparently transmitted through uplink and downlink direct transmission signaling. The Iu signaling connection includes UE authentication, radio access bearer (RAB), radio bearer (RB) and radio link (RL) establishment procedures.

It can be seen from Fig. 1 that in the existing WCDMA system call setup process, the access layer process and the non-access layer process are performed serially, and the ground resource establishment and air resource establishment of the access layer are also serially performed. However, the way of serially processing signaling will inevitably lead to low processing efficiency.

Through the analysis, it can be seen that in most cases, the state machine of the non-access layer has nothing to do with the access layer. Only when the non-access layer relies on the access relevant. When the state machine of the non-access layer has nothing to do with the access layer, parallel signaling may be considered for processing. Similarly, ground resources and air resources can also be established in parallel, and if any resource allocation fails on the network side, the entire resource allocation fails. Based on this point, the present invention realizes the reduction of call delay, which will be described in detail below.

As shown in Fig. 2, the present invention is realized by improving the existing WCDMA system call signaling.

When UTRAN triggers UE to perform RRC connection, UE sends RRC Connect Setup Request (RRC connection establishment request) message to RNC, which carries the Initial Direct Transfer (initial direct transfer) message of air interface; RNC receives the RRC Connect Setup Request After the message, organize the INITIAL DIRECTTRANSFER message (the message contains the CM SERVICE REQUEST (CM service request) message) to be transparently forwarded to the CN, transparently forward the UE's non-access layer message to the CN, start the non-access layer process, and at the same time Initiate the establishment of access layer resources. The present invention realizes the parallel execution of the non-access layer process and the access layer process by sending the CM (connection management) SERVICEREQUEST message in advance.

For the RNC, the message 11' is an interaction process between the downlink direct transmission message and the uplink direct transmission message. Since the present invention adopts the concurrent processing of the access layer and the non-access layer, the downlink direct transmission in the message 11' interaction may be received by the RNC before the message 9'. In order to ensure the correct sending of the message sequence, the RNC buffers the downlink direct transmission The transmitted message 11' is sent after receiving the message 9' (RRC connection is completed), thus ensuring the sequence of subsequent messages.

For the ground resource establishment and the air resource establishment of the access layer during the RRC connection process, the present invention also adopts a parallel manner for processing. After the RNC receives the aforementioned RRC Connect Setup Request message, it will allocate corresponding resources according to the current network resource situation, and send it to the UE through the RRC Connect Setup (RRC connection establishment) message, and at the same time perform the radio link (RL) and bearer of the Iub port The establishment of (RB) and frame protocol (FP) makes air resources and ground resources (involved in messages 4', 5', 6', 7', 8') parallelly established.

Similarly, for the Iu signaling connection process, the parallel establishment of ground resources and air resources can also be used.

For the messages 18' to 27' of the access layer in Figure 2, after the RNC receives the radio access bearer assignment request (RAB ASSIGNMENT REQUEST) from the CN, it simultaneously establishes air resources and ground resources, that is, first sends the air interface The Radio Bearer Setup (wireless bearer setup) message, and then carry out the allocation of resources (Iu port, Iub port) on the ground (related to message signaling 20', 21', 22', 23', 24', 25').

Since the air interface resource establishment delay of the current system is longer than the ground resource establishment delay, the UE does not know whether the network side uses a parallel or serial mode for resource allocation. For the case where the air interface resource establishment delay may be shorter than the ground resource establishment delay after the WCDMA system evolves, since the UE uses the confirmation mode to send the response message, the retransmission mechanism of the message can ensure that the network side receives the UE response message.

Because the present invention parallelizes the access process and the non-access process, the present invention reduces a response process between the non-access layer messages 9 and 11 in the original call flow; since the establishment process of air resources and ground resources is parallel, This will certainly reduce the less time-consuming process of those two setups. For the current situation that the establishment time of air interface resources is longer than the establishment time of ground resources, the present invention reduces the time occupied by the establishment of ground resources represented by messages 2-5, 19-24 in FIG. 1 .

The present invention is not limited to the call establishment process, but also applicable to signaling processes such as location update, routing area update, etc., and can also obviously reduce the delay of these signaling processes. Without departing from the spirit and essence of the present invention, those skilled in the art can also make other corresponding changes and deformations according to the present invention, but these corresponding changes and deformations should all belong to the scope of protection of the appended claims of the present invention .

Claims (6)

1. A method for reducing call set-up time in a wideband code division multiple access system, characterized in that the method may further comprise the steps: (1) The terrestrial radio access network triggers the user terminal to perform a radio resource control connection, and the user terminal sends a radio resource control connection establishment request message to the radio network controller in the terrestrial radio access network, and the message carries initial direct message; (2) After the radio network controller receives the radio resource control connection establishment request message, it transparently transmits the non-access layer connection management service request message contained in the initial direct transmission message to the core network, and simultaneously initiates the ground wireless The establishment process of access layer resources in the access network, so as to realize the parallel execution of non-access layer and access layer signaling; (3) When the radio network controller receives the non-access stratum signaling that needs to be downloaded, it judges whether the radio resource control connection has been established, and if it has been established, directly downloads the non-access stratum signaling; if not After completion, the non-access stratum signaling is cached, and the non-access stratum signaling is issued immediately after receiving the radio resource control connection establishment completion message. 2. The method for reducing call set-up time in a wideband code division multiple access system according to claim 1, characterized in that, for radio resource control connections, in the step (2) the terrestrial wireless access network access layer resources The establishment process is as follows: The radio network controller first sends a radio resource control connection establishment message to the user terminal according to the current network resources to establish air resources, and at the same time establishes a radio link, a bearer, and a frame protocol of the Iub port, so that air resources and Ground resources are built in parallel. 3. The method for reducing the call set-up time in the wideband code division multiple access system according to claim 1 is characterized in that, for the Iu signaling connection, the terrestrial wireless access network access layer resources in the step (2) The establishment process is as follows: After receiving the radio access bearer assignment message sent by the core network, the radio network controller first sends a radio bearer establishment message to the user terminal to establish air resources; The establishment of resources between the core networks and the establishment of access layer resources in the terrestrial wireless access network enable parallel establishment of air resources and ground resources during the Iu signaling connection process. 4. The method for reducing call set-up time in a wideband code division multiple access system according to claim 2, wherein the radio resource control connection establishment message sent by the network controller to the user terminal is in the connection management service Immediately after the request message is sent. 5. The method for reducing the call setup time in the WCDMA system according to claim 3, characterized in that the establishment process of the air resources in the WCDMA system is delayed from the establishment process of the ground resources. 6. The method for reducing call set-up time in a wideband code division multiple access system according to claim 3, characterized in that if any of the air resources and ground resources fails to be allocated, the entire resource allocation fails.

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