JP2000286851A - Communication controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conduct dynamic band control for every data flow with respect to outgoing data flow from a network to a mobile terminal in mobile communication. SOLUTION: This communication controller is provided with a buffer that buffers a fixed length packet stream (data chain) 401 resulting from dividing a received fixed length packet. The length of the data chain 401 is changed on the basis of a band control signal from an external device. Moreover, a timing when reading each data chain 401 from the buffer is changed on response to the band control signal. Furthermore, the buffer informs the external device of a state of the buffer as traffic quantity information. The external device outputs the band control signal in response to the traffic quantity information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling a band of a fixed-length packet inputted by identifying a data flow and transmitting the fixed-length packet to a radio apparatus in synchronization with an external periodic timing signal.

[0002]

2. Description of the Related Art In today's digital communication network, in addition to a conventional wired communication network using a metallic wire or an optical fiber, a communication network using a radio as a signal transmission medium, such as a mobile communication network, is increasing. . This mobile communication network is also compatible with existing mobile communication networks, as shown in the “Mobile Communication Handbook” published by Ohm on pages 217 to 251 and 301 to 326.
TM communication network (Synchronous Transfer Mode) communication network: "Easy Digital Switching" No. 29,
A PDC (Personal Digital Cellurar) for transmitting a signal in a time slot in the same manner as a PDC (Time Division Communication Network for transmitting a signal in a time slot divided in a synchronized frame as shown on page 30). ) Or PHS
(Personal Handyphone System) Communication network and "Easy Digital Mobile Communication" No. 32 to 3 published by the Telecommunications Association
CDMA (Code Division Multiple A) that performs communication by modulating using a different code for each signal as shown on page 6
ccess) Communication network exists. Among them, wideband CDMA (hereinafter, W-CDMA) shown on page 85 and thereafter of “Nikkei Electronics No. 680” issued by Nikkei BP.
(Referred to as Wideband CDMA)) is attracting attention as a communication system capable of transmitting and receiving signals of various types and speeds such as voice, image, and high-speed data with the same quality as existing wired communication networks even when moving at high speed. It is a communication network that is expected to be rapidly introduced.

On the other hand, the current communication network is an STM communication network, "Basic knowledge of data transmission" No. 128-1 issued by the Telecommunication Association.
"B-ISD" issued by Ohmsha, a packet communication network that carries signals by carrying signals on variable-length packets shown on page 33
Asynchronous Transfer Mode Communication Network (hereinafter referred to as ATM) which carries out communication by adding a signal to a fixed-length packet called a cell shown on pages 64 to 79 of "N Picture and Reader".
nsfer Mode) called a communication network), and furthermore, “Introduction to Mastering TCP / IP”, No. 98-10, issued by Ohmsha.
There are various communication networks such as an IP network (Internet) that carries a signal on a variable-length packet called an IP packet shown on page 3 and communicates the IP packet according to a procedure called an Internet Protocol (IP). Image and data media are communicated.

[0004]

In recent years, mobile packet networks including the Internet and PDC-P (PDC-Packet) have been rapidly expanding. Internet Protocol (RFC79), which is used on the Internet and is a de facto standard communication protocol in packet communication.
1, see http://www.ietf.org/rfc.html), so far, no consideration has been given to controlling the data communication band or the like in consideration of the data flow. That is, the most primitive method of transmitting as much data as possible when the communication path is not congested and transmitting no data when the communication path is congested has been adopted in the order in which the data arrives. The problem with this method is that it is not possible to distinguish between a data flow in which a delay such as a moving image is not allowed but data may be slightly missing, and a data flow in which a delay such as an e-mail is allowed but data is not missing. In other words, it ignores the nature of the data flow. Especially in the case of congestion, the above problem is fatal, and unless the data is treated separately according to the nature of the data flow, it is not possible to determine which data should be given priority when the communication path is congested, and delays It can be undesirable to send e-mails that allow for sending before videos that do not allow for delay. Therefore, it is considered that it will be necessary in the future to improve this point, for example, by allocating a larger band to the transmission of the moving image than the e-mail and transmitting the moving image first in consideration of the data flow. In other words, in the next-generation communication network, QoS (Quality of Service) control including the data transmission band is considered to be an important technology.

[0005] This QoS control includes band control, delay control, priority control, reliability control, and the like. Among them, band control that affects communication speed is considered to be important. Bandwidth refers to the amount of data that can be transmitted within a certain time, and is generally bps (bit p
er second). Controlling this is referred to as bandwidth control, and bandwidth control that is conscious of data flow has hardly been performed in the Internet as described above. In addition, since voice communications with fixed bandwidths have been the mainstream in public mobile communication networks, bandwidth is set at the time of contract for voice communications in the case of data communications, and in most cases it cannot be changed dynamically during communications. Met.

[0006] An object of the present invention is to provide a mobile packet communication network system in which moving pictures, voice, e-mail,
Bandwidth control for each data flow having different properties such as WWW,
Moreover, the present invention is to make it possible to dynamically change the band during communication.

In mobile communication, the band is the narrowest in the radio section, and it is not necessary to perform normal band control in the wired section in the mobile communication network for the upstream data flow from the mobile station to the mobile communication network. Therefore, more specifically, the present invention relates to a downstream data flow from a network to a mobile device in a mobile packet communication network system in which data communication data of various media such as moving images, voices, e-mails, and WWWs are mixed. An object of the present invention is to enable dynamic band change for each data flow during communication.

[0008]

In order to dynamically change the bandwidth according to the amount of data communication data during communication, communication data of a data flow is monitored in addition to the mechanism for dynamically changing the bandwidth. There is a need.

In wireless communication, for example, W-CDMA, information is transmitted while synchronizing with a certain period of 10 milliseconds in a wireless section between a mobile communication network and a mobile device. Therefore, in the downstream data flow from the network to the mobile device, it is necessary to transmit data at a certain period in order to transmit information wirelessly.

Therefore, the present invention increases or decreases the bandwidth of a data flow during communication according to the communication data amount of the data flow, and converts the input fixed-length packet into a smaller fixed-length packet sequence for wireless transmission. The signal is divided and transmitted to the wireless device in synchronization with an external periodic timing signal. Specifically, the communication control device according to the present invention includes the following means.

In order to dynamically change the bandwidth of the data flow based on a bandwidth control signal from an external device according to the communication data amount of the data flow during communication, the input fixed-length packet is reduced to a smaller fixed-length packet. A first means for dividing into a packet sequence (hereinafter referred to as a data chain) and buffering the packet sequence is provided. In the first means, data of each data flow is divided into a number determined by the band control signal to form a data chain, and the length of the chain of the data chain indicates the size of the band.

Further, there is provided a second means for giving the read timing of each data chain determined from the band control signal to each data chain. In the second means, an arbitrary FN that monotonically increases can be given to each data chain, and the size of the band is represented by how to increase the FN to be given.

Further, in synchronization with a periodic timing signal from the outside, the data chain is read from a buffer for each data flow and transmitted to the radio apparatus. A third means is provided for notifying, as traffic amount information, a state of a buffer for temporarily storing the data chain to an external device that generates a band control signal for a data flow. In the third means, the data chains with the identifiers to be read at the time are read from each buffer one by one at regular intervals,
Bandwidth control is performed by transmitting the data to the wireless device, and the amount of data used for the buffer and the stored data chain for each data flow are provided in order to provide traffic amount information used when the external device generates the band control signal. , And the amount of data read from the buffer and the like are notified to the external device as traffic amount information.

The above three means are combined to enable dynamic band change during communication.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a communication control device according to the present invention,
One example of a communication network configuration using this device and a dynamic band changing method during communication by this device will be described with reference to the drawings.

FIG. 1 is a network configuration diagram showing a configuration example of a communication network using the communication control device of the present invention.

The communication network includes a CDMA communication network 100 including a network device 1 (hereinafter sometimes abbreviated as GW) including the communication control device of the present invention and a switching system 2 for connecting heterogeneous networks. , WCDMA,
A mobile communication network 101 such as PDC, PHS, etc .; an ATM communication network (for example, a cell relay network) 102 for transmitting and receiving information using ATM cells; an IP communication network (for example, an OCN provided by NTT) 103 for transmitting and receiving information using IP packets; An STM communication network (for example, a digital switching network provided by NTT or an ITM
NS64 communication network) 104 and the like.

The GW 1 is connected to the mobile communication network 101, controls the mobile communication network 101, and terminates and converts signals specific to the mobile communication network.

FIG. 2 is a schematic diagram of a communication network using the communication control device according to the present invention. A communication control device 201 according to the present invention, a wireless device BS for wirelessly transmitting data, a terminal CS for wirelessly receiving data, a traffic control device 202 for transmitting a band control signal, and a network for relaying the external network 203 and the communication control device 201 The figure shows a case where data flows from an external network to a terminal in the network including the device 2. It is also assumed that the input from the network device 2 to the communication control device 201 has already been identified with the data flow. The traffic amount information collected by the communication control device 201 is notified to the traffic control device 202. In addition to the traffic amount information, the traffic control device 202 also considers the traffic quality information notified from the wireless device BS and the network device 2, The bandwidth is calculated for each data flow in the communication control device 201, and is notified to the communication control device 201 as a band control signal. The traffic amount information is notified to the traffic control device 202 periodically or by a request from an external device. The band control signal is transmitted to the communication control device 20 every time the band needs to be changed.
1 is notified. Based on this control signal, the communication control device 2
01, the band is controlled for each data flow and the radio equipment B
Send data to S.

Further, in the case of the direction of the flow from the terminal CS to the external network, since the band of the wireless section between the terminal CS and the wireless device BS is usually the narrowest, the wired section from the wireless device BS to the external network 203 is band controlled. Do not do.

FIG. 3 illustrates the operation of the buffer in the communication control device 201 and the network device 2. The LLC frame 301 is obtained by dividing an IP packet into a predetermined length, and performs a delay control of a data flow for each terminal in a queue 302 for each terminal, and a delay of a bundle of data flows for each wireless device in a queue 303 for each wireless device. Perform control. In the delay control referred to here, since there is an upper limit on the total communication bandwidth to each terminal or each wireless device, data is temporarily stored so that the total bandwidth of data flow passing through each terminal or each wireless device does not exceed the upper limit. It means to store it in a buffer and delay it. The reason that the delay control exists in two stages is that the delay control is required separately for the wired section to the wireless device and the wireless section from the wireless device to the terminal. The wireless device queue 304 of the communication control device 201 also performs delay control for each wireless device. This is provided to absorb and adjust the transmission delay between the network device 2 and the communication control device 201. . In this way, each data flow queue (hereinafter referred to as a pipe) 3
At the time of input to the terminal 05, the sum of the bandwidths of all data flows passing through each terminal or each wireless device can be kept within the predetermined upper limit of the total communication bandwidth.
Even if only the operation of allocating the bandwidth to each data flow in 05 is performed, the total bandwidth of all pipes does not exceed the upper limit of the total communication bandwidth, and the network can deliver data to the terminal without losing data. Then, based on the band control signal from the external device in the pipe 305, band control is performed for each data flow and between data flows, and the MAC-PDU 306
Is output.

When storing an LLC frame in a pipe,
The LLC frame is further divided into a certain length for wireless transmission, and FIG. 4 shows this state. A MAC-PDU is obtained by dividing the LLC frame, and a group of several MAC-PDUs is hereinafter referred to as a data chain 401.
The FN (Frame Number) is an identifier for synchronizing between the wireless device and the mobile device, and specifies a time at which the data chain is read from the pipe. Therefore, it can be used as a data chain identifier.

FIG. 5 shows the logical configuration of the pipe in detail. A pipe 305 is prepared for each data flow 501, and an LLC frame is stored here for each data flow. Each LLC frame is divided and connected in the form of a data chain 401 and stored. Next, the reading device 5
In step 02, one data chain is read from each pipe at a constant period, and transmitted to the wireless device. The reading device is a device that reads a data chain provided with the FN from each pipe at a time designated by the FN. 504
Indicates traffic amount information to be notified to an external device such as the bandwidth of each pipe, the number of stored data chains, and the like, and 503 indicates a band control signal from the external device.

When the LLC frame is stored in the pipe, the data chain is further divided into data chains in consideration of an information transmission structure in a wireless section (hereinafter referred to as a wireless frame). That is, the logical structure of the radio frame is as shown by 602 in FIG.
Several subframes consisting of a header part called CL and a data part of MAC-PDU are included during a certain period of time (for example, 10 milliseconds in W-CDMA). That's because I took it. The FN at 602 is the same as the FN of the data chain 401 and is used for synchronization between the wireless device and the terminal. The FN identifies the data chain and the terminal arranges the FN in the order of FN. The original packet can be restored. SFN in 306 is a subframe number, and indicates the order of MAC-PDU in a certain data chain. This corresponds to RCN or RSCN at 602. By making a data chain in a pipe in consideration of a radio frame in this way, band control can be performed very easily, for the following reasons.

In wireless communication, for example, W-CDMA, the structure of a wireless frame differs depending on the information transmission speed (band used per unit time). When the information transmission speed of a certain data flow is high, the number of subframes used by the data flow to be sent in a fixed time (10 milliseconds in W-CDMA) is increased, and when the speed is low, the number of subframes used by the data flow is increased. Reduce. When this is applied to the data chain, MAC-PD
The number of U corresponds to the information transmission speed (used band) as it is, and the used band can be controlled by increasing or decreasing the number. Because the data chain is read from the pipe once every fixed period (10 milliseconds in W-CDMA), it is determined by the physical conditions of the radio.
This is because band control is performed if only the amount of data read at a time is controlled. Therefore, by setting the data to be read from the pipe in the form of a data chain, the number of chains can be controlled and the band of the data flow of the pipe can be easily controlled.

FIG. 7 shows a method for realizing various bands by a data chain. As an example, five bands are shown. Of the five bands, 701 is the maximum bandwidth, 705 is the minimum bandwidth, and 702 to 704 represent the middle. In 701, the number of MAC-PDUs in each data chain is 3, and 18 MAC-PDUs can be transmitted in the time from FN = 1 to FN = 6 (hereinafter referred to as T). Similarly, in 702, 12 transmissions are possible. In 703, the number of MAC-PDUs in one data chain is 3 and the same as 701, but since the value of FN is skipped by one, after reading the data chain once, read once until the next read. rest. Therefore, during the time T, 9 MAC-
Can send PDU. In 704, since there is one MAC-PDU in one data chain, six M-PDUs in time T
AC-PDU can be transmitted. In 705, since one FN value is skipped, three MAC-PDUs can be transmitted within the time T. As described above, the bandwidth is changed by using the size of the MAC-PDU as one unit, but the FN value can be added discretely, so that the bandwidth can be changed in a pseudo-unit smaller than the size of the MAC-PDU. There is.

FIG. 8 shows how the transition between bands 701 to 705 is actually performed. As described above, a band control signal is notified from an external device in order to control the number of chains and how to apply the FN.
The contents to be notified are the number of the pipe to be controlled, the number of chains after the change (hereinafter referred to as L), the value of the FN specifying when to change, and the next data chain after reading one data chain. This is the number of times that reading is suspended until reading (hereinafter referred to as D). After receiving the notification of the band control signal, the communication control device 201 divides the input LLC frame sequence into a data chain having L MAC-PDUs after the data chain corresponding to the specified FN value in the specified pipe. , Store in a pipe. FIG.
Shows an example in which the bandwidth is increased and the bandwidth is decreased. Shows a case where the data chain of FN = 1 already exists in the pipe, and FN = 9
Up to the data chain, the number of MAC-PDUs is 3, and F
From the data chain of N = 10 to MA in the chain
The number of C-PDUs changes from 3 to 5. At this time, since the value of D is 0, the value of FN assigned to the next data chain is 11, and the number of MAC-PDUs is also 5. Thereafter, the same operation is repeated until a band control signal is further notified. Then, the number of MAC-PDUs in the chain changes from 2 to 1 from the data chain corresponding to FN = 7. D
Is 1, the FN of the next data chain is 9 instead of 8, skipping one, and is 11 after that. Or later,
The same is repeated until a band control signal is notified.

When the band is changed by the external notification as described above, a problem may occur in which the data chain of the designated FN already exists in the pipe. This corresponds to the case of FIG. 8 where the data chain of FN = 11 already exists in the pipe when the external band control signal is notified, and the external band control signal is delayed more than expected by the external device. It is thought to occur when it arrives. Resolving this problem in a pipe requires reconfiguring the data chain. As a method of realizing the data chain on the memory, a method of arranging pointers to the head of the MAC-PDU is considered. In this case, only the operation of exchanging the pointers is sufficient, and the processing amount is not so large. However, these are extra processes, and an external device needs to perform control for notifying a band control signal so that this problem does not occur.

The traffic amount information to be notified to the external device is stored in each pipe, L representing the current band of each pipe, the number of times D reading is suspended until the next data chain is read out after reading out the data chain once, and stored in each pipe. The number of data chains and the amount of data read from each pipe per unit time. The amount of data read from each pipe in a unit time is realized by counting the number of read MAC-PDUs. Then, it notifies the external device of the traffic amount information, for example, once every 10 seconds.

FIG. 9 shows a state where a limited band is optimized by using these two data flows when there are two data flows. The number of data chains stored in each pipe is considered to be proportional to the size of the communication data of that flow, and the bandwidth of the flow in which many data chains are stored is increased, and only a small number of data chains are stored. Reducing the bandwidth of an empty flow results in an efficient use of the limited bandwidth, ie, an optimized allocation of bandwidth between the two data flows. Therefore, as shown in FIG. 9, a certain reference value is provided for the number of data chains stored in the pipe (5 in FIG. 9), and a pipe in which the data chains are stored exceeding this reference value (in FIG. The bandwidth of 1) (the number of chains L in the data chain) is increased, and the bandwidth of the pipe (the pipe 2 in FIG. 9) in which the stored data chains are smaller than the reference value is reduced. At this time, by keeping the sum of the increased band and the decreased band at 0, the total bandwidth is kept constant. Here, L of the pipe 1 is increased by 1 and L of the pipe 2 is decreased by 1. This makes it possible to perform relative bandwidth control between data flows, and to perform optimal bandwidth control even when a sudden increase or decrease in the amount of communication data suddenly occurs in a data flow specific to packet communication. Becomes possible. Further, the above control can be applied to three or more data flows.

[0031]

According to the present invention, in the mobile packet communication network, the bandwidth of the data flow is dynamically adjusted by a bandwidth control signal from an external device according to the communication data amount of the data flow toward the downstream mobile station during communication. Can be changed to

Further, according to the present invention, the value of the FN designating the timing of reading the data chain can be flexibly given, such as by giving the data chain discretely, in combination with increasing / decreasing the number of data chains. 0
It is possible to flexibly change a very wide band from a very small band close to the maximum to a physical upper limit of radio, for example, 2 Mbps which is currently being standardized in W-CDMA.

Further, according to the present invention, by adjusting the number of data chains stored in the pipe for each data flow, the band between the data flows is relatively controlled, and the limited band is optimized so that each data flow is controlled. It is possible to sort into flows.

[Brief description of the drawings]

FIG. 1 is a network configuration diagram showing a configuration example of a communication network using a network device including a communication control device of the present invention.

FIG. 2 is a diagram showing an example of a network configuration using the communication control device of the present invention.

FIG. 3 is a diagram showing an example of a cooperative operation of the communication control device of the present invention with another device in the network.

FIG. 4 is a diagram showing a method of configuring a data chain.

FIG. 5 is a buffer that enables dynamic bandwidth change for each data flow.

FIG. 6 is a logical configuration diagram of an information structure of a wireless section.

FIG. 7 is a diagram showing a method for realizing different bands by a data chain.

FIG. 8 is a diagram showing a method of dynamically changing a band.

FIG. 9 is a diagram illustrating a method of relatively controlling a band between data flows.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Communication network control system (GW) 2 ... Switching system (NS) 100 ... Multimedia communication network 101 ... Mobile communication network 102 ... ATM communication network 103 ... IP communication network 104 ... mobile communication network 106 ... communication terminal BS ... base station CS ... mobile terminal 201 ... communication control device according to the present invention 202 ... communication data control device 203 ... external network 204: Data flow 301: Data frame obtained by dividing an IP packet into a fixed length 302: Delay control queue for each mobile wireless terminal in the network device 303: For each wireless device in the network device Delay control queue 304: Delay control queue for each wireless device in the communication control device of the present invention 305: Dynamic bandwidth control queue for each data flow (Pipe) 306 MAC-PDU 401 Data chain 501 Data flow 502 Data chain readout device 503 External band control signal 504 Flow information per flow 601 -Wireless sub-frame header section 602 ... Wireless sub-frame data section 701 to 705 ... Change in the configuration of the data chain due to the size of the band.

Claims (3)

[Claims] An input fixed-length packet is divided into a fixed-length packet sequence (hereinafter, referred to as a "data chain") designated by a band control signal from an external device, and the data chain is divided for each data flow. (Hereinafter referred to as "pipe"), and an identifier (hereinafter referred to as "FN (frame number)") which designates a time at which a data chain is read from each of the plurality of pipes according to the band control signal. ), Means for reading a data chain having an FN designated by the timing signal from each pipe in synchronization with an external periodic timing signal, and a state of each pipe of the plurality of pipes. And a means for notifying the external device of the above as traffic amount information. 2. The communication control apparatus according to claim 1, wherein said means for assigning an FN assigns a value that monotonically increases as an FN to each data chain in each pipe. 3. When a number of data chains exceeding a predetermined reference value is stored in any one of the plurality of pipes, the band of the plurality of pipes is increased, and any one of the plurality of pipes is increased. When a smaller number of data chains are stored in the pipe than the predetermined reference value, the bandwidth of the pipe is reduced, and the bandwidth of each pipe is reduced so that the increase and decrease of these bandwidths are offset. The communication control device according to claim 1, further comprising a control unit.