Abstract:
The present invention discloses a method for messages transmission in a simplified way, UE transmitting the messages to the network through the lower layer, the method includes following steps: if the lower layer indicates the message has been transmitted successfully, then starting timer, otherwise, ending the current procedure; if the UE has received response from the network before the timer expires, stopping the timer; otherwise, ending the current procedure. The method can effectively avoid unnecessary operations, and reduce energy consumption of the UE.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This is a continuation of International Application No. PCT/CN2005/001979, which was filed on Nov. 23, 2005, and which, in turn, claimed the benefit of Chinese Patent Application No. 200510056893.2, which was filed on Mar. 28, 2005, the entire disclosures of which are hereby incorporated herein by reference. 
     BACKGROUND OF THE DISCLOSURE 
     1. Field of the Technology 
     The present invention relates to messages transmitting techniques, and more particularly to a method for transmitting the lower layer message of User Equipment (UE) in Multimedia Broadcast/Multicast Service (MBMS) system in a simplified way. 
     2. Background of the Invention 
     Multicast and broadcast are the techniques for transmitting data from one data source to multiple targets. In traditional mobile communication networks, Cell Multicast Service or Cell Broadcast Service (CBS) allow low speed data to be transmitted to all subscribers through cell shared broadcast channels, which belongs to message services. 
     Nowadays, simple telephone and message services can no longer meet requirements of subscribers on mobile communication; sharp development of the Internet has brought many new diversified mobile multimedia services. Wherein, some mobile multimedia services such as video on demand, television broadcasting, video conference, online education and interactive games etc., require that several subscribers can receive the identical data simultaneously. Compared with common data services, these mobile multimedia services have the properties of large quantity of data, long duration and are delay-sensitive. The current Internet protocol (IP) multicast and broadcast techniques can only be applied to the wired IP communication networks rather than mobile communication networks, because the mobile communication network has special network architecture, function entities and radio interfaces, which are different from those of wired communication IP network. 
     In order to make full use of Mobile Communication network resources, International Organization for the third Generation Standardization (3GPP) introduced the concept of multicast and broadcast (MBMS), and thereby provides Point To Multipoint (PTM) service where one data source transmits data to multiple targets in Mobile Communication networks, to share network resources and increase Utilization Ratio of network resources, and especially idle interface resources. The MBMS defined by 3GPP can not only implement multicast and broadcast of low speed messages such as plain text, but also multicast and broadcast of high speed multimedia services, which undoubtedly meets the requirements of future mobile data development. 
       FIG. 1  is a schematic diagram illustrating architecture of a radio network that supports Broadcast/Multicast service, as shown in  FIG. 1 , in prior 3GPP, entity of the radio network that supports Broadcast/Multicast service is Broadcast/Multicast service server (BM-SC)  101 , and BM-SC  101  links TPF GGSN (Gateway GPRS Support Node)  102  through Gmb interface or Gi interface, one BM-SC  101  can connect with multiple TPF GGSN  102 ; TPF GGSN  102  further connects to SGSN (Serving GPRS Support Node)  103  via Gn/Gp interface, one GGSN  102  can connect with multiple SGSN  103 ; SGSN  103  can link UTRAN (Universal Terrestrial Radio Access Network)  104  of Universal Mobile Telecommunication System (UMTS) through Iu interface, and then UTRAN  104  connects with UE  106  via Uu interface, SGSN  103  can also connect with GERAN (GSM/EDGE Radio Access Network)  105  in GSM (Global System of Mobile communication) through Iu/Gb interface, and GERAN  105  further connects with UE  107  via Um interface. Wherein, both GGSN and SGSN are nodes of Core Network (CN) in radio network. 
     From the network structure shown in  FIG. 1  it can be seen that, in order to support MBMS service, Broadcast/Multicast service center, i.e. BM-SC, the mobile network function entity was introduced into 3G Mobile Communication system, the BM-SC is the entrance to content providers, which can be used for the authorization and initiating MBMS bearer service in mobile networks and transmitting MBMS contents based on preset schedules. Besides, MBMS related functions have also been added to function entities such as UE, UTRAN, GERAN, SGSN and GGSN etc. 
     MBMS consists of multicast mode and broadcast mode, wherein, multicast mode requires users to subscribe in relevant Multicast group, activate the services and generate corresponding charge information. The difference between multicast mode and broadcast mode in service requirement results in dissimilar operation flow between the two modes, as shown in  FIG. 2  and  FIG. 3 ,  FIG. 2  is a schematic flowchart illustrating operation in MBMS Multicast mode, while  FIG. 3  is a schematic flowchart illustrating operation in MBMS Broadcast mode. 
     As shown in  FIG. 2 , processing steps involved in MBMS Multicast service includes: Subscription, Service announcement, Joining, Session Start, MBMS notification, Data transmit, Session Stop and Leaving. Wherein, the UE can subscribe wanted MBMS services in Subscription step; BM-SC may announce currently available services during Service announcement step; Joining step refers to the MBMS multicast service activating process, when the UE informs the network its willingness to be a member of current multicast group and accept multicast data of corresponding services, an MBMS UE context will be generated in the network and UE that joined the multicast group to record UE information during the joining step; in Session Start step, BM-SC will prepare data transmitting, and notify the network to establish bearer resource of relevant Core Network and access network; during MBMS notification step, the UE will be notified that MBMS multicast session will start soon; during Data transmit step, BM-SC transmits the data to the UE through bearer resource established in Session Start step, wherein, MBMS service has two modes while transmitting between UTRAN and UE: Point To Multipoint (PTM) mode and Point To Point (PTP) mode, wherein, PTM mode means that identical data will be transmitted through MTCH logical channels, and available to all UEs that subscribed Multicast service or were interested in Broadcast service, while PTP mode means data are transmitted via DTCH logical channel and available only to one corresponding UE; in Session Stop step, the bearer resource established in Session Start step will be freed; and subscribers in the group will leave the multicast group in Leaving step, which means that the UE will no longer accept Multicast data, and corresponding MBMS UE context will also be deleted in the step. 
     Now referring to  FIG. 3 , processing steps involved in MBMS Broadcast service are similar to these of MBMS Multicast service, however, it is unnecessary to implement Subscription process and Joining process before Session Start, and also unnecessary to implement leaving step after Session Stop. 
     During Data transmit steps of Multicast mode operation and Broadcast mode operation, MBMS service has two modes for transmitting message between UTRAN and UE: Point To Multipoint (PTM) mode and Point To Point (PTP) mode. Wherein, PTM MODE means that identical data will be transmitted through MBMS PTM service channel (MTCH), and available to all UE that subscribed Multicast service or were interested in Broadcast service; while PTP mode means data is transmitted via dedicated service channel (DTCH) and available only to one corresponding UE. 
     In MBMS PTM transmit mode, relevant radio control message includes service information, access information, radio bearer information and Frequency Layer Convergence (FLC) information etc., which are transmitted by Radio Resource Control (RRC) through logical channel such as MBMS PTM Control Channel (MCCH). Protocol Stack structure of MCCH is shown in  FIG. 4 , Protocol units of the MCCH can be listed from top to bottom as follows: RRC layer, Radio Link Control (RLC) layer, Medium Access Control (MAC) layer and Physical (PHY) layer. 
     In MBMS system, in order to determine optimum transport mode for each assigned MBMS service, the system introduced MBMS counting process, i.e. UTRAN employing counting process to estimate number of UEs which are interested in certain MBMS service in a cell, and the counting process differs according to different status of the UE. 
     According to whether RRC connection has been established in current Mobile Communication system, status of the UE can be classified into Idle mode and RRC Connected mode. Wherein, the UE that has not established RRC connection with UTRAN equipment stays in Idle mode, where, the UE can only be distinguished through identifier of Non-Access Stadium (NAS) such as International mobile subscriber identity (IMSI); and the UE that has established RRC connection with UTRAN equipment stays in RRC Connected mode, where, a Radio Network Temporary Identity (RNTI) has been assigned for the UE to act as identity of the UE in common transport channels. 
     Moreover, the UEs in RRC Connected mode can be further classified into different status according to different layer of RRC connection and type of transport channels available to the UE, wherein, the UE in CELL_PCH status, CELL_FACH status and CELL_DCH status can be identified on the cell layer, while the UE in URA_PCH status can be identified on UTRAN Registration Area (URA) layer. A dedicated physical channel will be assigned for the UE in CELL_DCH status, therefore, the UE can use the dedicated transport channel or shared channel or their combination; the UE in CELL_FACH status needs downlink to continuously monitor a common transport channel (FACH, Forward Access Channel.), and uplink to assign random common channel (RACH, Random Access Channel); the UE in CELL_PCH and URA_PCH status adopts Discontinuous Reception (DRX) means to monitor a Paging Channel (PCH) through relevant PICH channel, however, there are no uplink movement under these two statuses. 
     Generally, MBMS counting process is initiated by Radio Network Controller (RNC), when service Session Start step needs establishing radio bearer and RNC considers it is necessary, RNC issues notification message and sends probability factor simultaneously through the access information, after receiving the notification messages, the UE under Idle mode may acquire access information, and initiate RRC connection setup process to respond to counting process if probability factor check is passed; while the UE under URA_PCH status and CELL_PCH status will acquire access information after receiving the notification messages, and initiate cell update process to respond to counting process if probability factor check is passed; and the UE under CELL_FACH status will respond to counting process through other means after receiving the notification messages. Wherein, implementing probability factor check simply is to avoid collision of different UEs during accessing step and make the accessing process of UE discrete as much as possible, the method further includes following steps: generating a random number within 0˜1 and comparing the generated random number with designated probability factor, if the random number is less than the designated probability factor, then the probability factor check is passed, otherwise the probability factor checking process fails. 
     During counting process of the UE under Idle mode, the UE initiates the RRC connection establishment procedure through transmitting the RRC connection request message RRC CONNECTION REQUEST, when the RRC CONNECTION REQUEST message is used for the MBMS counting procedure, the RRC transmitting steps for the UE is as follows: 
     After contents of RRC CONNECTION REQUEST message having been configured, the UE transmitting the configured RRC CONNECTION REQUEST message on the uplink Common Control Channel (CCCH), and setting the value of the state variable V 300  to 1; the RRC CONNECTION REQUEST message is transmitted via the RLC layer and MAC layer of Protocol Stack at the UE, after transmitting the message, MAC layer generating an indication to indicate whether the message had been transmitted successfully, and starting timer T 318  simultaneously, and setting the value of counter N 300  to 0. Wherein, V 300 , N 300  and T 318  are the variable names of the state variable, the counter and the timer regulated in standard protocol respectively. 
     Before timer T 318  expires, if the UE has received the response message transmitted from UTRAN, then it indicates that RRC connection establishment procedure of the UE succeeds, then stopping timer T 318 ; otherwise, waiting for the response message transmitted from the network until the timer expires. When timer T 318  expires, if the value of state variable V 300  is greater than that of counter N 300 , then the RRC connection establishment procedure of the UE fails and the UE turning into the Idle mode; besides, the UE implementing a series of operations regulated by the protocol after the UE turning from the RRC Connected mode into the Idle mode, and then finishing the entire processing procedures; otherwise, sending a new RRC CONNECTION REQUEST message on the uplink CCCH, and enabling the value of state variable V 300  to increase by degrees. 
     From the above processing procedures, it can be seen that, the prior technical schemes have the following disadvantages: at present, no matter whether MAC layer transmitting the RRC CONNECTION REQUEST message succeeds or not, the UE initiates timer T 318  in any case, however, if MAC layer informs that the RRC CONNECTION REQUEST message transmitting procedure fails, then it is unnecessary to start timer T 318  any more, the counting process will be finished in this case. 
     SUMMARY OF THE INVENTION 
     In view of the above, the present invention provides a method for messages transmission in a simplified way. The technical solution of the present invention is achieved as follows: 
     A method for messages transmission in a simplified way, including, transmitting a message from an User Equipment (UE) to a network through a lower layer, 
     starting a timer if the lower layer indicates the message has been transmitted successfully, or ending a current procedure if the lower layer indicates the message has been transmitted unsuccessfully; 
     stopping the timer if the UE has received a response from the network before the timer expires, or ending the current procedure if the UE has not received a response from the network before the timer expires. 
     According to above scheme, before the processing of the lower layer indicating that the message has been transmitted successfully, the method further includes: setting an initial value of a counter, and setting a threshold value of the counter; 
     before the processing of ending the current procedure if the lower layer indicating the message has been transmitted unsuccessfully, the method further includes: starting the timer if the current value of the counter is not greater than the threshold value of the counter, or ending the current procedure if the current value of the counter is greater than the threshold value of the counter; 
     before the processing of ending the current procedure if the UE has not received the response from the network before the timer expires, the method further includes: retransmitting the message to the network, correcting the current value of the counter, and returning to the processing of the lower layer indicating that the message has been transmitted successfully if the current value of the counter is not greater than the threshold value of the counter; or ending the current procedure if the current value of the counter is greater than the threshold value of the counter. 
     Wherein, the setting initial value of the counter is 1; and the preset threshold value of the counter is 0. 
     Wherein, the processing of setting the threshold value of the counter includes: the network setting the threshold value of the counter, and sending the threshold value to the UE through a standardized message. 
     In above scheme, if the preset threshold value of the counter is the maximum of the current counter, then the processing of correcting the current value of the counter includes increasing the current value of the counter by degrees; 
     or, if the preset threshold value of the counter is the minimum of the current counter, then the processing of correcting the current value of the counter includes descending the current value of the counter by degrees. 
     In above scheme, the method further includes: setting the initial value of the counter to 1 before determining whether the message has been transmitted successfully; 
     setting the threshold value of the counter to 0 before determining whether the message has been transmitted successfully or while starting the timer; and 
     checking and confirming that the current value of the counter is greater than the threshold value of the counter before ending the current procedure if the UE has not received the response from the network before the timer expires. 
     Wherein, the method further includes: the UE turning into an idle mode, and implementing all operations from a connection mode to the idle mode before ending the current procedure. 
     Wherein, the message includes a Radio Resource Control (RRC) message or a counting response message; the lower layer includes a Medium Access Control (MAC) layer. 
     Wherein, the RRC message includes a RRC connection request message or a cell update message. 
     In above scheme, the method further includes: the UE turning into the idle mode and implementing all operations from the connection mode to the idle mode before ending the current procedure. 
     In the method for messages transmission in a simplified way according to the present invention, as the UE can implement different operations on subsequent procedures based on indications showing success or failure in message transmit in MAC layer, the timer is not necessary to be started after failing in message transmit, and therefore the present invention can avoid unnecessary timer operation, reduce consumption of UE resources and power, and further reduce operation cost of the UE. For the case when it is necessary to transmit the message only once, the present invention can retrench the counter and state variable setting and checking steps, therefore, simplifying relevant operation steps and reducing complexity of the procedures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram illustrating architecture of a radio network that supports Broadcast/Multicast service; 
         FIG. 2  is a schematic flowchart illustrating the service procedure in MBMS Multicast mode; 
         FIG. 3  is a schematic flowchart illustrating the service procedure in MBMS Broadcast mode; 
         FIG. 4  is a schematic diagram illustrating Protocol Stack structure of MCCH; 
         FIG. 5  is a schematic flowchart illustrating implementing procedures of one embodiment in accordance with the present invention; 
         FIG. 6  is a schematic flowchart illustrating implementing procedures of another embodiment in accordance with the present invention; and 
         FIG. 7  is a schematic flowchart illustrating implementing procedures of another embodiment in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the present invention, whether to start the timer or not can be determined based on the indication showing success or failure in message transmitting at the lower layer. Wherein, the message refers to the message which can tell current UE of RNC to receive the given MBMS services, such as a RRC message or other counting response messages, wherein, the RRC message can be a RRC CONNECTION REQUEST message or a cell update message etc.; the lower layer is a MAC layer. Following steps just take the case that transmitting the RRC CONNECTION REQUEST message, and the MAC layer generating indications showing success or failure in the message transmit as example. 
     In practical application, the RRC CONNECTION REQUEST message can be transmitted once or several times, correspondingly, under the conditions of different message transmitting times, the processing procedures of the counter and the state variable may consequently differ. The RRC CONNECTION REQUEST message transmitting procedure in accordance with the present invention will be described in more detail hereinafter with reference to the drawings and embodiments. 
     Embodiment One 
     In this embodiment, the RRC CONNECTION REQUEST message is transmitted only once, and the processing procedures of the counter and the state variable during the RRC CONNECTION REQUEST message transmitting procedure are implemented according to regulations of the existing standard protocol. 
     As shown in  FIG. 5 , the processing procedure of transmitting the RRC CONNECTION REQUEST message in this embodiment includes the following steps: 
     Step  501 : after setting contents of the RRC CONNECTION REQUEST message, the UE sending the preset RRC CONNECTION REQUEST message on uplink CCCH channel, and setting the value of the state variable V 300  to 1. 
     Step  502  to  503 : if the MAC layer indicating the message has been transmitted successfully, then starting the timer T 318 , and setting the value of the counter N 300  to 0; otherwise, going to Step  508 . 
     In practice, the value of the counter N 300  can be set while starting the timer; it can also be set before Step  502 . 
     Step  504  to  505 : if the UE has received the response message transmitted from UTRAN before the timer T 318  expires, then stopping the timer T 318 , showing the RRC connection establishment procedure of the UE is successful, and then ending the current procedure; otherwise, going to Step  506 . 
     Step  506  to  507 : checking whether the value of the state variable V 300  is greater than that of the counter N 300 , if yes, then going to Step  508 ; otherwise, transmitting a new RRC CONNECTION REQUEST message on the uplink CCCH channel, correcting the value of the state variable V 300 , and returning to Step  502 . 
     Wherein, the value of the counter N 300  corresponds to the threshold value of the state variable V 300 . For the reason that this embodiment examines the case of transmitting the RRC CONNECTION REQUEST message only once, therefore value setting of the counter N 300  and the state variable V 300  exclusively refer to enabling the value of the state variable V 300  is greater than that of the counter N 300 , so as to avoid retransmitting of the RRC CONNECTION REQUEST message. 
     Step  508 : once the RRC connection establishment procedure of the UE fails, the UE turning into the Idle mode, and implementing a series of operations regulated by protocol after turning from the RRC Connected mode to the Idle mode, and then ending the current procedure. 
     Embodiment Two 
     In this embodiment, the RRC CONNECTION REQUEST message is transmitted only once, and for this reason, no procedures on the counter and the state variable will be considered, including setting, comparing and checking of the counter and the state variable. 
     As shown in  FIG. 6 , the processing procedure of transmitting the RRC CONNECTION REQUEST message in this embodiment includes the following steps: 
     Step  601 : After setting the contents of the RRC CONNECTION REQUEST message, the UE transmitting the preset RRC CONNECTION REQUEST message on the uplink CCCH channel. 
     Step  602  to  603 : if the MAC layer indicating the message has been transmitted successfully, starting the timer T 318 ; otherwise, going to Step  606 . 
     Step  604  to  605 : if the UE has received the response message transmitted from UTRAN before the timer T 318  expires, showing the RRC connection establishment procedure of the UE is successful, and ending the current procedure; otherwise, going to Step  606 . 
     Step  606 : Once the RRC connection establishment procedure of the UE fails, the UE turning into the Idle mode, and implementing a series of operations regulated by protocol after turning from the RRC Connected mode to the Idle mode, and then ending the current procedure. 
     Embodiment Three 
     In this embodiment, the RRC CONNECTION REQUEST message is transmitted several times. Now referring to  FIG. 7 , the processing procedures of transmitting the RRC CONNECTION REQUEST message in this embodiment includes the following steps: 
     Step  701 : After setting the contents of the RRC CONNECTION REQUEST message, the UE transmitting the preset RRC CONNECTION REQUEST message on the uplink CCCH channel, and setting the value of the state variable V 300  to 1; at same time, the UE setting the value of the counter N 300 . Wherein, the initial value of the counter N 300  is set by the network, and the network transmitting the value to the UE through one standardized message, the UE then setting the initial value of the counter based on the parameters in the message, practical processing steps follow the prior procedures regulated by the standard, no details will be discussed hereinafter. 
     Step  702  to  704 : if the MAC layer indicating the message has been transmitted successfully, starting the timer T 318 ; otherwise, checking whether the value of the state variable V 300  is not greater than that of counter N 300 , if yes, then starting the timer T 318 ; otherwise, going to Step  709 . 
     Step  705  to  706 : if the UE has received the response message transmitted from UTRAN before the timer T 318  expires, showing the RRC connection establishment procedure of the UE is successful, and then ending the current procedure; otherwise, going to Step  707 . 
     Step  707  to  708 : checking whether the value of the state variable V 300  is not greater than that of the counter, if yes, then UE transmitting a new RRC CONNECTION REQUEST message on the uplink CCCH channel, and correcting the value of the state variable V 300 , and returning to Step  702 ; otherwise, going to Step  709 . 
     Wherein, the value of the counter N 300  corresponds to the threshold value of the state variable V 300 , the state variable V 300  corresponds to the practical counting value indicating times of message transmit. If setting the value of the state variable V 300  to 1 and the value of the counter N 300  to 0, then it will become a special case of this embodiment, in this case, it corresponds to transmitting the RRC CONNECTION REQUEST message only once. 
     In step  708 , there are two means to correct the value of the state variable V 300 : one of which is that, if the value of the counter N 300  is the maximum of the state variable V 300  value, then correcting refers to increasing the value of the state variable V 300  by degrees, for instance, adding 1 at one time; another is that, if the value of the counter N 300  is the minimum of the state variable V 300  value, then correcting refers to descending the value of the state variable V 300  by degrees, for instance, reducing 1 at one time. In this embodiment, it refers to increasing the value of the state variable V 300  by degrees. 
     Step  709 : Once the RRC connection establishment procedure of the UE fails, the UE turning into the Idle mode, and implementing a series of operations regulated by protocol after turning from the RRC Connected mode to the Idle mode, and then ending the current procedure. 
     Although certain preferred embodiments of the present invention have been described herein, it should be understood various variations and/or modifications can be made without departing from the spirit and the scope of the present invention as set forth in the following claims.