KR100866209B1 - Method for cfn determination between rnc and node-b in 3gpp imt-2000 system - Google Patents

Abstract

end. The technical field to which the invention described in the claims belongs

The present invention relates to a method for determining a CFN in a base station and a wireless network control period in an asynchronous mobile communication system.

I. The technical problem to be solved by the invention

The present invention relates to a method of determining a CFN using a communication frame between a base station and a wireless network controller in an asynchronous mobile communication system.

All. Summary of Solution of the Invention

The method according to the present invention transmits a forward node synchronous control frame from a radio network controller to a base station. At this time, the time when the forward node synchronous control frame is transmitted from the radio network controller and the time received by the base station is obtained. Also, the base station receiving the forward node synchronization control frame transmits the reverse node synchronization control frame to the radio network controller. The time obtained above is transmitted to the reverse node synchronization control frame. In addition, the reverse node synchronization control frame is transmitted to the radio network controller including the time transmitted from the base station. Obtain the time when the reverse node synchronization control frame is received by the radio network controller. A round trip delay is obtained based on the four time points.

In the transmission channel synchronization procedure, when the wireless network controller transmits the forward transmission synchronization control frame to the base station, the base station designates a predetermined range to be received to determine whether the forward transmission synchronization control frame is received in the range. When the received frame is received out of the range to be received, the above-described time difference is transmitted to the reverse transmission synchronization control frame. By repeating such a process, the information of the forward transmission synchronization control frame is received in the range to be received.

In determining the connection frame number, a value of a transport channel type and a time of arrival of the transport channel are analyzed. With the above values, the reception time of the node ratio that has received the transmission synchronization frame and the time sent out to the air from the node ratio are obtained, and the difference between the reception time and the sent time is obtained.

The time difference is converted into a frame of 10 ms units. In addition, after obtaining a difference between the connection frame number transmitted by the radio network controller and the time frame is transmitted by the base station to the air, a round trip delay is added to the difference to determine the next connection frame number to be transmitted by the radio network controller.

Asynchronous, synchronous control frame, time adjustment, CFN

Description

METHODS FOR CFN DETERMINATION BETWEEN RNC AND NODE-B IN 3GPP IMT-2000 SYSTEM}             

1 is a control flowchart of a forward node desynchronization procedure to which the present invention is applied.

2 is a control flowchart of a reverse node non-synchronization procedure to which the present invention is applied.

3 is a control flowchart of a forward transmission channel synchronization procedure to which the present invention is applied;

4 is a control flowchart of a reverse transmission channel synchronization procedure and a reverse transmission time adjustment to which the present invention is applied.

5 is a control flowchart for determining a connection frame number (CFN) to which the present invention is applied.

The present invention relates to a method for determining a connection frame number (CFN) at an interface between a radio network controller (RNC) and a base station (Node B), and more particularly, to a method for determining a connection frame number in an asynchronous manner.

The conventional mobile communication system uses a method of transmitting data in accordance with time zones of a transmitter and a receiver using a GPS satellite, and the GPS satellite used in the synchronization method is a satellite developed by the United States for military use. Therefore, due to the rejection and economic problems, Europe uses asynchronous data transmission. Hereinafter, the method of synchronizing the transmitting side and the receiving side in the synchronous method will be described.

In the case of the synchronous method, a channel used to obtain pseudo noise code timing is a forward pilot channel. The forward pilot channel is data provided so that all mobile stations (MSs) operating within the cell area of a particular base station can obtain the pseudo noise code timing, i.e. all the mobile stations can obtain synchronization with the base station. Is a spread channel with only pseudo noise codes unmodulated and always transmitted. Since the mode system constituting the synchronous method is mutually synchronized between the base stations by GPS satellites, each of the base stations uses the same pseudo noise code, and only gives a different offset to each of the base stations, It is possible to distinguish. That is, the starting point of pseudo random number codes of all base stations are matched in time using GPS, and each base station uses a synchronization structure that matches the time of the terminal belonging to itself.

Therefore, since time synchronization is performed between base stations and mobile stations around the world, the starting points of the pseudo random number codes can be matched. This feature allows all mobile stations to use the same code and to delay the start of the code by the number of chips unique to each mobile station so that it behaves like a separate pseudorandom code of a different kind. Since the number of time delay chips of the unique pseudo-random code of every mobile station is determined according to the protocol defined by the device serial number of the mobile station, the base station can know exactly the number of time delay chips of a specific mobile station, which can be used to determine A pseudo random code synchronization with the mobile station is obtained.

As described above, the radio network controller, the base station, and the mobile station all have the same synchronization time provided by the GPS satellites. Therefore, when a transmission frame is transmitted by the wireless network controller, when a transmission time is input to the frame and transmitted, the base station can determine the transmission time and determine the order of the received frames.

However, the asynchronous method does not use GPS satellites and the mobile station is assigned a different scrambling code for each base station, and the mobile station first calculates the slot timing from the common national synchronization channel to find the nearest base station. The timing of the frame is then calculated from the secondary synchronization channel. In more detail, first, a cell specific code for distinguishing each of the base stations is assigned to each of the base stations Node B constituting the asynchronous system. Each of the base stations constituting the asynchronous system with a code is identified. As an example, 512 cells constituting the asynchronous system and one base station for each cell are assumed to be 512 base stations constituting the asynchronous system. Then, different cell identification codes are assigned to each of the 512 base stations, and each of the base stations constituting the asynchronous system is identified with a cell identification code assigned to each of the 512 base stations.

However, since the mobile station must search for each of the base stations constituting the asynchronous system in order to search for the base station to which the mobile station belongs, the mobile station must perform a search for each of the 512 base stations constituting the asynchronous system. will be. Since the mobile station searches for each of the 512 base stations constituting the asynchronous system, it checks each phase of the code constituting the cell discrimination code of each of the 512 base stations. Searching for cells takes a lot of time. Therefore, since it is inefficient to apply the general cell search algorithm for each base station constituting the asynchronous system, the mobile station implements a multi-stage cell search algorithm. In order to implement the multi-level cell search algorithm, a plurality of base stations, for example, 512 base stations belonging to the asynchronous system are classified into a predetermined number of groups, for example, 64 groups (Groups 0 to Group 63). A different group identification code is assigned to each of the classified 64 groups to distinguish a base station group, and each base station group is composed of eight base stations. In addition, since each of the eight base stations has a different code for spreading a common pilot channel (CPICH), the base station to which the mobile station belongs to has a scrambling code for spreading the channel. You can navigate.                         

The multi-step cell search process described above is composed of the following three-step cell search process. First, the first step cell search process is a process in which a mobile station receives a primary synchronization channel (P-SCH) signal transmitted from a base station and finds and synchronizes slot timing received at maximum power. In the two-stage cell search process, frame synchronization and mobile station itself belong to a second synchronization channel (S-SCH: Secondary Synchronization CHannel) received by the mobile station from the base station after receiving the slot timing information found in the first-stage cell search process. This is a process of detecting a group of base stations. In the step 3 cell search, the mobile station finally searches for the base station to which the mobile station belongs with a common pilot channel (CPICH) signal transmitted from the base station based on the frame synchronization and base station group information found in the step 2 cell search. It's a process.

As described above, in the asynchronous method, unlike the synchronous method, synchronization between the radio network controller and the base station is performed by the codes of the base stations. When a large amount of information such as voice or video is transmitted from a wireless network controller to a base station, it is not transmitted in one frame. In this case, transmission is divided into several frames. However, when a certain amount of frames are transmitted by the wireless network controller, the base station does not receive them in the order in which they are transmitted. In order to prevent this, the wireless network controller needs to number the transmission frames and transmit them.

 Accordingly, an object of the present invention is to provide a method for transmitting a numbered frame to be transmitted from the radio network controller to the base station.

Another object of the present invention is to provide a method of receiving normal data without generating an error in data by transmitting a numbered frame to be transmitted.

It is another object of the present invention to provide efficient data management by shortening the transmission time of data by receiving normally without error of data.

The method of the present invention for achieving the above objects is a frame forwarded from the radio network controller to the base station by the forward node synchronization control frame, and then received by the base station by the reverse node synchronization control frame at the base station receiving the wireless network controller Send a frame to A round trip delay (RTD) is obtained by obtaining a time at which the radio network controller and the base station transmit / receive a frame.

In order to achieve the above object, a method of the present invention transmits a forward transmission synchronization control frame from a radio network controller to a base station, and the base station transmits a reverse transmission synchronization control frame to the radio network controller when the frame is received. The wireless network controller and the base station may perform a timing adjustment procedure to receive data in a range of frames desired by the base station.

The method of the present invention for achieving the above object is characterized by determining the next connection frame number to be transmitted using the round trip delay obtained above, the connection frame number transmitted by the radio network controller and the time transmitted by the base station to the air. It is done.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, detailed descriptions of related known functions or configurations will be omitted when it is determined that the gist of the present invention may be unnecessarily obscured.

1 is a control flow diagram illustrating a procedure of downlink Node B synchronization to which the present invention is applied. The forward node out-of-synchronization is used to find a reference time to match different reference times between the radio network controller (hereinafter referred to as RNC) and the base station (hereinafter referred to as Node B). In other words, it synchronizes by grasping time information between RNC and Node B. 1 illustrates a process of transmitting a control frame to the Node B by the RNC to solve this problem. Hereinafter, an operation principle of the forward node desynchronization to which the present invention is applied will be described in detail with reference to FIG. 1.

Maintain Idle mode at step 100 of forward node out-of-synchronization. The standby state is a state in which a signal is not transmitted or received and is prepared for signal transmission and reception.

In step 105 of forward node out-of-synchronization, information of node out-of-synchronization is received. Node synchronization is a process for synchronizing between the RNC and Node B. Therefore, information for synchronization between the RNC and Node B is received, and other received information is deleted.

In step 110 of forward node desynchronization, information of T1 is obtained. The T1 refers to the time at which the RNC transmits a control frame to synchronize with the Node B. The RNC has an RNC Frame Number Counter (hereinafter referred to as RFN) that is incremented every 10 ms. The RFN has a frame from 0 to 4095. Therefore, the value of T1 has an arbitrary value from 0 to 4095.

Step 115 of forward node out-of-synchronization creates a forward node synchronization frame. The forward node synchronization frame refers to a frame randomly generated by the RNC to synchronize the RNC with the Node B. That is, T1 in step (110) refers to the time at which the forward node synchronization frame is transmitted from the RNC to Node B.

In step 120 of forward node desynchronization, a forward node synchronization frame is transmitted from the RNC to the Node B through a transport channel.

In step 125 of forward node synchronization, the state of the RNC is changed to a node synchronization state. The node synchronization state refers to a state for receiving information transmitted to the Node B as a response to the forward synchronization frame transmitted by the RNC.

2 is a control flowchart illustrating a procedure of reverse node synchronization to which the present invention is applied. The reverse node synchronization is a process of transmitting a response frame from the Node B to the RNC as a response to the process of FIG. 1 from the Node B to the RNC. Hereinafter, an operation principle of reverse node synchronization to which the present invention is applied will be described with reference to FIG. 2.

In step 200 of reverse node synchronization, the node synchronization state of step 125 is maintained.

In step 205 of backward node synchronization, an uplink node synchronization frame is generated. The reverse node synchronization frame is the same frame as the forward node synchronization frame and is a frame transmitted from the Node B to the RNC. The reverse node synchronization frame stores the values of T1, T2, and T3. The value of T2 refers to the time when the forward link synchronization frame is received at Node B. The Node B also has a Node B frame number (hereinafter referred to as BFN) that is increased every 10ms like the RNC. The BFN has a frame from 0 to 4095. Therefore, the value of T2 has an arbitrary frame value from 0 to 4095. The value of the RFN of the RNC may be different from the value of the BFN of the Node B. The T3 refers to a time at which the frame is transmitted from the Node B to the RNC as the reverse node synchronization control example. In addition, the value of the T3 may be larger or smaller than the value of the T2. This is because the value of the BFN is repeatedly countered from 0 to 4095 frames.

In step 210 of reverse node synchronization, a reverse node synchronization frame is transmitted from the Node B to the RNC.

In step 215 of reverse node synchronization, the time when the reverse node synchronization frame is received by the RNC is recorded. The time when the reverse node synchronization frame is received at the RNC is called T4. Therefore, in this step, all of the values of T1, T2, T3, and T4 are stored as described above.

In step 220 of reverse node synchronization, a round trip delay (hereinafter referred to as RTD) is obtained. The RTD takes a delay time for transmitting a frame from the RNC to the Node B in the step of forward node synchronization and a delay time for transmitting a frame from the Node B to the RNC in the step of reverse node synchronization. The sum of the delay times. Expressed as an expression, RTD = (T2-T1) + (T4-T3). The RTD value will be applied to find the CFN to be described below.

In step 225 of reverse node synchronization, the RTD value obtained in step 220 is stored. In step 230 of reverse node synchronization, a transition is made to a Transport Synchronization State. The transmission synchronization state is described below as a state for performing the process of FIG. 3.

3 is a control flowchart of forward transport channel synchronization to which the present invention is applied. Transport channel synchronization is useful in the application of all forward transport channels. Hereinafter, an operation of forward transport channel synchronization to which the present invention is applied will be described in detail with reference to FIG. 3.

In step 300 of forward transport channel synchronization, the transmission synchronization state, which is the state of step 230, is maintained. The state is a state for confirming synchronization of a channel from the RNC to the Node B.

In step 305 of forward transport channel synchronization, values of RFN and RTD are obtained.

In step 310 of forward transport channel synchronization, the forward transport channel synchronization control frame is transmitted to the Node B using a frame protocol.

 In step 315 of forward transport channel synchronization, the RFN maintains a state of arrival (TOA) at the RFN.

4 is a control flowchart of reverse transport channel synchronization to which the present invention is applied. The reason for performing the steps of FIG. 3 and FIG. 4 is a function for receiving a frame sent by the RNC within the range of the window in Node B at the appropriate frame position set by Node B based on the RTD stored above. Do this. Accordingly, the RNC continuously transmits the frame to the Node B at an appropriate time, and as a response, the Node B transmits newly modified information to the RNC when it is out of a set range. Hereinafter, an operation of reverse transport channel synchronization to which the present invention is applied will be described in detail with reference to FIG. 4.

In step 400 of reverse transport channel synchronization, the arrival time set in step 320 is maintained. In step (400), the reception information other than the reception of the set arrival time is not responded to.

In step 405 of reverse transport channel synchronization, the arrival time described above is stored. The arrival time described above will be described in more detail as follows.

Node B has a range specified as a window for the transmission channel and has time for a frame to be received. The point where the predetermined range of the window starts is called a time of arrival window start point (hereinafter referred to as TOAWS). The point at which the predetermined range of the window ends is referred to as a time of arrival window endpoint (hereinafter referred to as TOAWE). When the data of the arrival time is received, the difference between the above-described TOAWE and the TOAWE. The arrival time has a positive value when received earlier than the TOAWE, and the arrival time has a negative value when received later than the TOAWE.

In step 410 of backward transmission channel synchronization, time is adjusted so that a frame arriving at the base station is received at a desired reception time.

In step 415 of backward transmission channel synchronization, the arrival time stored in step 405 is loaded on a backward transmission time adjustment control frame and transmitted to the RNC.

In step 420 of backward transmission channel synchronization, the frame is analyzed, the CFN and the arrival time value are stored, and the control proceeds to step 425. Through this process, the frame transmitted from the RNC is received in the window set in the Node B.

Hereinafter, a method of determining CFN, which is the content of the present invention, will be described with reference to FIG. 5.

 Step 500 for determining the CFN determines the type of transport channel. Determine if the transport channel is a paging channel (PCH) and if it is not a paging channel. The maximum size of the paging channel frame is 4096 frames, and if it is not a paging channel frame, the maximum size of the frame is 256 frames. This is to determine an appropriate CFN by determining the number of frames of a channel to be transmitted.

Step 505 for determining CFN determines the value of arrival time. As described above, when the RNC is to transmit data from the RNC to the Node B, it receives the data within the window size set in the Node B transmission channel. Therefore, in this process, it is determined whether the value of the arrival time is a positive value or a negative value. If the arrival time value is positive, toa = rcvTOA-X is obtained. If the arrival time value is negative, toa = X-rcvTOA is obtained. (Where X is 163840 for the paging channel and 10240 for the paging channel). As described above, the paging channel has a maximum frame of 4096 frames and a non-paging channel of 256 frames.

In step 510 of determining the CFN, the reception time of the Node B to receive the forward sync frame based on the previous CFN and the arrival time obtained above is obtained, and the value of modValue is obtained using the reception time.

In step 515 for determining the CFN, a time for transmitting data from the Node B to the air through a transmission channel is obtained. In step 520 of determining the CFN, a difference between a time at which data is received at the Node B obtained in step 510 and a time value at which the data is transmitted to the air from the Node B obtained in step 515 is determined. Obtain The time difference is a time at which the data stayed in the Node B.

In step 525 for determining CFN, the time difference obtained in step 520 is calculated in units of frames. That is, the time difference is calculated as one frame on the basis of 10 ms units. This is considered because data is transmitted in units of frames. If the obtained frame is less than or equal to two frames corresponding to the window size, the TTI2 frame is added. This is to prevent overlapping between two frames indicating the same window size when the frame reached first and the frame reached later are smaller than the difference in window size.

In step 530 for determining the CFN, the difference between the CFN transmitted by the RNC and the time that the Node B transmits the CFN to the air is obtained. This is to find the time it takes for the data transmitted from the RNC to be transmitted to the air through Node B.

In step 535 to determine the CFN, the RNC adds the round trip delay obtained in FIG. 2 to the value obtained in step 530 to determine the next CFN to be transmitted. By performing this process, the RNC transmits data in order of data, and the Node B receives the data in order.

As described above, the present invention has an advantage in implementing a function of determining a CFN for a data frame of a transmission channel generated on a frame protocol between a radio network controller (RNC) and a base station (Node B) using a synchronization procedure defined in 3GPP. . As such, the radio network controller assigns a number to a frame of data to be transmitted to the base station and transmits the number to analyze the number of the data, thereby receiving the data without error of the data, and transmitting the data to the public from the base station. In addition, by determining the CFN between the radio network controller and the base station can save the time required for data transmission can enjoy an economic effect.

Claims (6)

A method of determining a connection frame number (CFN) for synchronization of a reverse transport channel in a wireless network controller of a mobile communication system, Obtaining the reception timing of the base station based on the arrival time obtained by the forwarding channel synchronization procedure and the previous connection frame number; Determining a transmission timing of the base station based on the reception timing, and calculating a difference between a connection frame number transmitted by the radio network controller and a connection frame number transmitted by the base station based on the determined transmission timing; And determining a final connection frame number to be transmitted by the wireless network controller by adding a round trip delay to the calculated difference between the two connection frame numbers. The method of claim 1, wherein the step of calculating a difference between the connection frame number transmitted by the radio network controller and the connection frame number transmitted by the base station is: Converting the timing difference between the transmission timing and the reception timing into a frame of a predetermined unit, and if the converted value is less than or equal to a request reception interval of the base station, increasing the transmission timing by a predetermined frame length Way. The method of claim 2, wherein the request reception interval of the base station, CFN determination method characterized in that two frame intervals, 20ms. 3. The method of claim 2, wherein the predetermined frame length is. CFN determination method characterized by one frame length having 10ms. The method of claim 2, wherein the predetermined frame length, CFN determination method, characterized in that two frame length, 20ms. The method of claim 2, wherein the predetermined frame length, CFN determination method characterized in that the four frame length, 40ms.

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