JP2004350229A - Atm cell shaping device and atm cell shaping method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate a gate array device and a physical memory accompanying the gate array device by carrying out a shaping process by a CPU. <P>SOLUTION: A decoded data frame is received and converted into in a shape of an ATM cell (step 12).The frame type of the converted ATM cell is determined (step 13), and if it is a control frame, the ATM cell is stored in a control frame area (step 19). If it is a data frame, the type of a channel is determined (step 14), and if it is a common channel, it is stored in a buffer for a common channel buffer (step 18). If it is a data frame, whether its VC is divided into two or more ATM cells or not is determined (step 15). If it is divided into two or more, it is stored into a shaping buffer (step 17), and if it is one, this one is set directly to a transmission queue (step 16). The main process is carried out by CPU and a processing memory is replaced by the memory of the CPU, so that a gate array device and a physical memory accompanying the gate array device can be eliminated. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ATM (asynchronous transfer mode) cell shaping apparatus and method, and more particularly, to an ATM traffic shaping apparatus that performs data transmission processing to a radio network controller in connection with a CDMA (code division multiple access) radio base station apparatus. And methods.
[0002]
[Prior art]
In the conventional ATM transfer method, fixed-length packets called cells are transferred. In an ATM network, cells on a virtual channel (VC) are multiplexed and transferred to a virtual path (VP), but multiplexing in the ATM transfer method is performed asynchronously. Therefore, when the signal passes through a multiplexing device, a switch, or the like, a cell delay fluctuation occurs due to a difference in waiting time in the buffer. Due to the cell delay fluctuation, a cell having a small interval is generated, and the traffic becomes burst traffic on the VP, thereby reducing the use efficiency of the network resources. As means for solving this problem, a virtual path (VP) shaping device has been proposed (for example, see Patent Document 1). The shaping means that the terminal controls the cell transmission characteristics on the terminal side so as to conform to a parameter related to the cell transmission speed predetermined between the terminal and the network.
[0003]
An outline of this conventional VP shaping device will be described with reference to FIG. In FIG. 7, # 1, # 2, and # 3 represent cells, and the cells advance from left to right in the figure. In FIG. 7, reference numeral 1 denotes a VP shaping device. The VP shaping device 51 includes a buffer 52 for accumulating cells, and a cell output control unit 53 for controlling cell output timing from the buffer 52. Reference numeral 54 denotes a VP multiplexer, which multiplexes an incoming VC and inputs the multiplexed VC to the VP shaping device 51.
[0004]
The operation of the VP shaping device 51 will be described.
The cells multiplexed by the VP multiplexer 54 arrive at the VP shaping device 51 in the order of # 1, # 2, and # 3, and are stored in the buffer 52. The cell output control unit 53 reads out the cells from the buffer 52 at predetermined intervals, and controls the cells so that the cells have a constant interval on the VP.
[0005]
In a CDMA radio system, a radio frame transmitted from a radio mobile station (MS) is decoded in a radio base station apparatus and converted into user data. Further, the user data is split and converted into ATM cells for transmission to a radio network controller (RNC). At this time, the data length of the user data differs depending on the service type used by each user. Each ATM cell is provided with an identifier (VC) used on the ATM line.
[0006]
Further, a peak cell interval based on the output interface speed is obtained for each VPI, a relative transmission time is calculated for each VCI according to a time based on the VPI peak cell interval, and then the cell transmission time based on the output interface speed is calculated. Is determined, and cells are transmitted from the cell buffer (for example, see Patent Document 2).
[0007]
An ATM cell composed of 53 bytes is transmitted over the line in ATM cell units. At this time, ATM cells having a plurality of identical identification numbers (VC) (user data divided into a plurality of cells) are continuously transmitted. I do. Accordingly, occupying the transmission band by a single VC must be avoided due to the nature of the present system in which a plurality of user data (a plurality of VCs) are handled and the timing of data transmission / reception is very important. . The processing used there is shaping processing.
[0008]
In the shaping processing, the transmission order of the ATM cells of the set VC is changed without changing the transmission order of a certain VC, and the received user data is evenly transmitted on the ATM line without depending on the data length of the VC. This is the process of sending to. FIG. 8 shows an example.
[0009]
FIG. 8 shows a procedure in which user data of different types A, B, C, and D are divided into ATM cells, shaped, and the ATM cells are transmitted to a radio network controller (RNC). As shown in FIG. 8, the user data processed by the CPU is converted into ATM cells, and the transmission order is such that user data received at a certain timing is evenly arranged in ATM cell units. By this processing, even if a specific user has long user data, there is no large delay in transmission of user data processed thereafter.
[0010]
This system has conventionally been realized by a logic circuit using a gate array (G / A) and a physical memory for storing data. FIG. 9 shows a flow of data in a conventional system and a transition of a data format between the CPU 1 and the G / A 3.
[0011]
The wireless frame 5 received by the CPU 1 is subjected to wireless frame processing (DECODER processing), and is temporarily buffered in the form of user data 6 in the SRAM 2 attached to the DSP 1. The buffered data is transmitted to the G / A 3 in the order in which the radio frame processing has been performed, and is stored in the G / A SRAM 4. The stored user data is converted into an ATM cell by G / A (see FIG. 2), subjected to a shaping process, and sent out onto a line.
[0012]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 07-212367 [Patent Document 2]
JP 08-125668 A
[Problems to be solved by the invention]
However, the conventional shaping processing technology requires a CPU-G / A interface, a gate array device, and an associated physical memory as shown in FIG. 9 from a wireless frame to an ATM cell. Therefore, problems such as an increase in component mounting area and weight, an increase in cost, an increase in power consumption, and the like become problems.
[0014]
For example, after receiving the wireless frame, the CPU performs a DECODER process to convert the data into user data. Each of the user data is numbered as identification information of each user. This number and the VC correspond to each other, and become a tag at the time of buffering when performing the shaping process. In the conventional buffering method, all areas corresponding to the VC are prepared in advance, and user data is stored therein. At this time, as the area size to be secured, it is necessary to prepare the maximum size that the user data can take. Therefore, assuming that the maximum size of the user data that can be taken by the user data is “X” and the number of assignable VCs is “Y”, a size of X × Y is required for the buffer.
[0015]
However, for example, when a certain user uses a service having user data of the maximum size, the number of VCs that can be set for the CPU decreases. VC can be set in the DSP.
FIG. 10 illustrates a conventional buffer usage when a user having each VC is set in the user data frame 10 of the VC code 1 and the user data frame 9 of the VC code X. In this conventional example, since each VC has a buffer size of the maximum Iub frame size, an unused buffer 11 is generated, and many areas are not used.
[0016]
According to the present invention, the shaping process is performed by the CPU, and the physical memory for shaping is covered by the memory of the CPU, thereby eliminating the need for the gate array device and the associated physical memory. It is another object of the present invention to provide an ATM cell shaping device and an ATM cell shaping method that reduce the size of a memory used by a CPU by optimizing a memory usage method.
[0017]
[Means for Solving the Problems]
In order to achieve this object, an ATM cell shaping apparatus according to the present invention comprises: a user data receiving means for receiving user data from a radio mobile station (MS) by a CDMA radio base station (NODE-B); CDMA radio base station (NODE-B), comprising: a memory address determining means for determining a memory address to be buffered in the CDMA radio base station (NODE-B); and a user data transmitting means for transmitting received user data to a radio network controller (RNC). ) Manages user data received from a wireless mobile device (MS).
[0018]
Further, the memory address determination means is configured as a processing step on software, and a process of transmitting control data (control signal) from the CDMA radio base station to the radio network controller is allocated in a transmission order having a higher priority than user data. It is preferable to identify user data received from a wireless mobile station (MS) that cannot perform shaping processing in the CDMA wireless base station, and buffer the identified user data.
[0019]
Further, a physical memory having a virtual matrix configuration is used for the processing of the user data. In the use of the physical memory, the data write address is used when buffering the user data in order to effectively use the physical memory. It is good to decide.
[0020]
An ATM cell shaping method according to a seventh aspect of the present invention is a user data receiving step in which a CDMA radio base station (NODE-B) receives user data from a radio mobile station (MS), and buffering is performed for each user on an ATM cell basis. And a user data transmitting step of transmitting received user data to a radio network controller (RNC). The CDMA radio base station (NODE-B) User data received from a mobile station (MS) may be managed.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of an ATM cell shaping apparatus and an ATM cell shaping method according to the present invention will be described in detail with reference to the accompanying drawings. Referring to FIGS. 1 to 6, there is shown an embodiment of an ATM cell shaping apparatus and an ATM cell shaping method according to the present invention.
[0022]
In the present invention, in order to cope with the above-mentioned conventional problems, a method of storing a buffer in a processed Iub frame unit without using a VC instead of having a buffer for each VC is used for buffer use. Further, even in an Iub frame, data that fits within one ATM cell is set in a transmission queue without being stored in this buffer.
[0023]
ATM cells of control frames that need to be transmitted immediately are set in the transmission queue in the order of reception without performing shaping. Further, in a data frame, the common channel may be subjected to Iub processing at the same timing at the same VC. For this reason, if shaping is performed and the transmission order is changed, there is a possibility that Iub frames cannot be reproduced at a higher level. Therefore, a dedicated buffer is prepared for the data frame of the common channel.
[0024]
(Description of configuration and operation)
In the present invention, the shaping process is performed by software. The software control by the CPU from the reception of the data frame by the CPU to the transmission of the ATM cell to the line in order to perform the shaping process will be described with reference to the flowchart of FIG.
[0025]
First, a decrypted data frame is received and converted into an ATM cell format [Process 1 (Step 12)]. The method of conversion to ATM is shown in FIG. Next, the frame type of the converted ATM cell is determined [decision A (step 13)], and if it is a control frame, the ATM cell is stored in the control frame area [process 2 (step 19)]. If it is a data frame, the channel type is determined [decision B (step 14)], and if it is a common channel, it is stored in the common channel buffer [process 3 (step 18)]. If it is a data frame, it is determined how many ATM cells the VC has been divided into [determination C (step 15)]. If it is two or more, it is stored in the shaping buffer [processing 4 (step 17)]. If there is only one, it is set to the transmission queue as it is [Process 5 (Step 16)].
[0026]
The data stored in each buffer is set in a transmission queue at an arbitrary timing and transmitted to an upper ATM line. The method of storing data in [Process 4 (Step 17)] will be described later. In order to perform the above processing, the configuration of the buffer to be prepared by the CPU is, as shown in FIG. 3, three areas of a control frame buffer, a common channel buffer, and a shaping buffer (23).
[0027]
Next, the method of storing ATM cells in the shaping buffer in [Process 4] in FIG. 1 is shown in FIG. 4 using a simplified buffer having a 4 × 5 matrix configuration. In the buffer, a row number (25) and a column number (24) are set from "0", and each column has a parameter "number of written areas (26)". This parameter is incremented each time data is stored in the column direction. Thus, the address of a cell in an arbitrary area is (row number, column number) (for example, the address of cell (27) shaded in (1) of FIG. 4 is (2, 3) ).
[0028]
After dividing and converting a certain data frame into ATM cells, the CPU searches the number of written areas (26) from the column number “0”. When the number of written areas is smaller than the maximum number of rows of the matrix (here, 4), the number of written areas in that column is the row number to be stored as it is. Then, subsequent ATM cells can be calculated from the number of written areas and the column numbers. The above processing will be described with reference to FIG.
[0029]
(2) “Store first to third Iubs (after ATM cell conversion)” in FIG. 4 represents an example of storing three pieces of user data (28, 29, 30). In this storage example, the number of written areas in each column is “3, 3, 2, 1, 0” from the “0” column. Next, when storing user data in which the number of ATM cells is further divided, in the first cell, when the number of written areas is searched from the 0th column, the “0” column is 3 and the number of rows is 4 Therefore, the writing area is determined as (3, 0). Subsequent cells are sequentially determined as (3,1), (2,2), (1,3), (0,4) from the number of written areas.
[0030]
That is, the row number for storing certain user data is the number of written areas at that time. As a result, in this process, the processed user data is sequentially stored in the buffer without considering the VC. According to this method, the buffer size for the number of all VCs having the longest area in the area for all VCs is not required, and further, as shown in (4) of FIG. The data is buffered in the specified form, and the memory is effectively used.
[0031]
As described above, the data stored as shown in FIG. 4 is stored in the memory map in the order of the control frame [C1], the common channel [R1], and the data frame [D1] as shown in FIG. Is done. After that, it is set in the transmission queue at an arbitrary timing and transmitted to the ATM line.
[0032]
(Explanation of the operation of the embodiment)
FIG. 6 shows a flow from the conversion of a radio frame into an ATM cell to transmission according to the present invention. In this system, the wireless frame 37 received by the CPU 36 is subjected to a shaping process and sent out onto an ATM line 38. In this embodiment, the processing is simplified because G / A (3) is not required, as compared with the conventional example shown in FIG.
[0033]
(Effects of the embodiment)
Hereinafter, a comparison result between a case where the shaping process is performed using the conventional gate array and a case where the shaping process is performed according to the present invention will be described, and an effect resulting from the comparison result will be described.
[0034]
There is no need for a gate array and its associated physical memory. As a result, for example, the component mounting area, the module weight, the hardware cost, and the interface between the gate array and each device need not be designed. Further, a series of processes can be performed because the process is performed by the CPU that performs the physical decoding, and the process can be performed at high speed. Further, the memory size required as a shaping buffer having a matrix structure can be reduced, and a memory use method with a small gap is advantageous for transfer processing.
[0035]
【The invention's effect】
As is clear from the above description, in the ATM cell shaping apparatus and the ATM cell shaping method of the present invention, the CDMA radio base station (NODE-B) receives user data from the radio mobile station (MS), A memory address to be buffered for each cell is determined, and the received user data is transmitted to a radio network controller (RNC). According to this procedure, the CDMA radio base station (NODE-B) manages the user data received from the radio mobile station (MS).
Based on the above procedure, there is no need for a gate array and its associated physical memory. As a result, it is possible to reduce the component mounting area, reduce the module weight, reduce the hardware cost, increase the processing speed, and the like.
[Brief description of the drawings]
FIG. 1 is a flowchart illustrating an example of software control according to an embodiment of an ATM cell shaping apparatus and an ATM cell shaping method of the present invention.
FIG. 2 is a diagram showing a procedure for receiving a data frame and converting the data frame into an ATM cell.
FIG. 3 is a diagram illustrating a configuration example of a buffer to be prepared by a CPU;
FIG. 4 is a simplified 4 × 5 buffer having a matrix configuration and shows a method of storing ATM cells in a shaping buffer.
FIG. 5 shows an example of setting stored data in a memory map and a transmission queue.
FIG. 6 shows a flow from conversion of a radio frame to an ATM cell to transmission.
FIG. 7 is a block diagram illustrating a configuration example of a conventional VP shaping device.
FIG. 8 is a diagram for explaining an example of a conventional processing procedure for uniformly transmitting data to an ATM line without depending on the data length of a VC.
FIG. 9 is a diagram showing a data flow in a conventional system and a transition of a data format between a CPU and G / A.
FIG. 10 illustrates a conventional buffer usage method.
[Explanation of symbols]
23 3 areas of shaping buffer 24 column number 25 row number 26 number of written areas 27 cells 28, 29, 30 user data 36 CPU
37 Radio frame 38 ATM line

Claims (7)

User data receiving means for the CDMA radio base station to receive user data from the radio mobile device;
A memory address determining means for determining a memory address to be buffered in an ATM cell unit for each user;
User data transmitting means for transmitting the received user data to the wireless network controller,
An ATM cell shaping device, wherein the CDMA radio base station manages user data received from the radio mobile station. 2. The ATM cell shaping device according to claim 1, wherein said memory address determining means is configured as a processing step on software. The ATM cell according to claim 1, wherein a process of transmitting control data (control signal) from the CDMA radio base station to the radio network controller is assigned in a transmission order having a higher priority than the user data. 4. Shaping device. The ATM according to any one of claims 1 to 3, wherein the CDMA wireless base station identifies user data received from the wireless mobile device that cannot perform shaping processing, and buffers the identified user data. Cell shaping device. 5. The ATM cell shaping device according to claim 1, wherein a physical memory having a virtual matrix configuration is used for processing the user data. 6. The ATM cell shaping apparatus according to claim 5, wherein in using the physical memory, a data write address is determined when buffering the user data in order to effectively use the physical memory. A user data receiving step in which the CDMA wireless base station receives user data from the wireless mobile device;
A memory address determining step of determining a memory address to be buffered in an ATM cell unit for each user;
Transmitting the received user data to a wireless network controller.
The ATM cell shaping method, wherein the CDMA wireless base station manages user data received from the wireless mobile device.

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