JP3364410B2 - Communication device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication device for performing call admission processing and priority control in an ATM adaptation layer when a wireless terminal supporting multimedia, for example, communicates through an ATM network.

[0002]

2. Description of the Related Art Up to now, wireless terminals have been used for mobile phones and PHS.
(Personal Handyphone System
They mainly deal with voice like em). Recently, a method capable of data transmission like PHS has been considered, but since the transmission speed is exactly the same as that of voice, it is common to treat it as traffic when viewed from the network side. . Therefore, it suffices to allocate the same band to all terminals and perform circuit-switching processing.

Recently, however, wideband CDMA (Co
de Division Multiple Access
The method called ss) attracted attention. Wide band C
It is considered that the DMA not only performs multimedia communication such as voice and data, but also supports different transmission rates depending on the media. For example, voice has a variation from several kbps to several tens kbps depending on the encoding system, while the maximum data is 2 Mbps.
It is necessary to support up to s. It is quite difficult to process the line in a time division manner, and especially since the data rate is not always constant at the peak rate, it is wasteful.

As a method of supporting such variable rate multimedia information, ATM (Asynch)
There is a "ronous Transfer Mode" communication. ATM technology is the most suitable infrastructure for handling multimedia. In the ATM technique, fixed-length packets called ATM cells are used to multiplex lines. One ATM cell can hold 48 bytes of information, but this is inefficient and not suitable for handling small things such as voice. Therefore, it has been devised to multiplex the information of a plurality of users into one ATM cell. This is AAL (ATM Adapt)
ation Layer) type 2. In AAL type 2, since users share one ATM cell, ANP (AAL2 Negot) is not directly used for normal Layer 3 signaling messages.
Iation Protocol) to enable simple call accommodation, but details of ANP have not been decided yet.

Further, since the call accommodated by using the ANP has different traffic characteristics, it is necessary to control the priority of the information transmission in accordance with the traffic characteristic. However, there is no fixed one at present.

[0006]

As described above, the AN
Regarding the acceptance of a call using P and the priority control in AAL type 2, there has been no fixed standard.

The present invention has been made in view of this point, and it is an object of the present invention to provide a simple and bandwidth-oriented signaling to an AAL type 2 for a wireless terminal having a lot of call processing including handover. To improve the efficiency, and to control the efficient transmission of each call in consideration of the characteristics of the wireless terminal and the network.

[0008]

In order to solve such a problem, a communication device according to claim 1 is a transmission device from a wireless terminal.
Multiple data storage accommodating different retention time
Corresponding to the retention time of the transmission data
Means for storing the transmission data in the buffer,
The buffers with the smallest allowable residence time
Means for sending the accumulated transmission data to the network side
Is larger than the cycle in which the transmission data arrives from the wireless terminal.
Correspondence in the buffer corresponding to the allowable dwell time
The allowable residence time for
And a means for changing to click. For example, AA
At least one is a system in which a wireless terminal communicates using L type 2, and the arrival period of a wireless frame, which is a unit of data transmission from the wireless terminal, is p, and the transmission data from the wireless terminal stays in the wireless base station. When the allowable time is q [x] (X = 1,2,3, ..., m) for each of m kinds of applications, q [x] and q [x] to p [q] for each q [x]
Of all positive values obtained by subtracting at least one time, excluding duplicates, from the smaller one to t [y] (y = 1,2,3, ..., n), and for each t [y], n Number of buffers are created, and the transmission data from the wireless terminal is put in the buffer having the same t [y] value as the stay allowable value, and the data is sent to the network side in order from the buffer with the smallest t [y] value. It is a thing.
Also, the value of t [y] in the buffer is
Is updated every period p that data arrives and is larger than p
Replace the buffer with the value of t [y] with the value of t [y] −p.
A buffer with a value of t [y] less than or equal to p is t [y]
And t [y] plus a multiple of p
Has the same allowable retention value as the
Replaced by the value of large q [x] and these replaced
Regarding the value of the buffer, t [y] again from the smallest value.
Timer tube of buffer such that (y = 1,2,3, ..., n)
It makes sense.

According to a second aspect of the present invention, there is provided the communication apparatus according to the first aspect, wherein the buffer free space is
The amount of data that can be sent during the residence time that corresponds to
The amount of data currently stored in the buffer and
A buffer with a corresponding smaller allowable residence time than the buffer
It is the value obtained by subtracting the amount of data currently stored in. An example
For example, the buffer having the value of t [1] is
The amount of data that can be sent in between is currently stored in the buffer
The value obtained by subtracting the amount of data
A buffer having the value of t [y] (y = 2,3, ..., n)
Is the amount of data that can be transmitted during the period t [y],
The buffers with the values [z] (z = 1, ..., y) have already been
The value obtained by subtracting the total amount of stored data is the empty buffer
It has capacity management.

A communication device according to claim 3 is a network
Stores the transmission data from the
A plurality of buffers corresponding to the residence time allowed and the transmission
The data is transferred to the buffer corresponding to the data retention time.
A means for accumulating send data and a corresponding minimum allowable retention time
From the buffer, the accumulated transmission data is
The means to send to the line terminal side and the transmission data from the wireless terminal
A bar corresponding to a residence time that is larger than the arrival period.
The corresponding residence allowable time in the buffer is
And a means to cyclically change each cycle
To have. For example, using AAL type 2
One is a system in which wireless terminals communicate,
Radio frame transmission cycle, which is the unit of data transmission to the end
End the ATM adaptation layer type 2
At an exchange that retains data for wireless terminals
Allowable time is q [x] (X =
1,2,3, ..., m), one of these q [x]
Decide time t [1] and t [y] up to the maximum value qmax of q [x]
= Yt [1] t [y] (y = 1,2,3, ..., qmax / t [1]
) And qmax / t [1] bags for each t [y].
For wireless terminals that create new buffers and enter new buffers
The transmission data of the buffer is buffered based on the retention time.
In the buffer with the smallest value of t [y].
Take it out and output it. Also, the buffer
The value of t [y] of is updated every period t [1], and the value of t [1]
The value of the buffer is qmax, and the other values of t [y] are
Buffer timer tube that is replaced by t [y-1]
Have reason.

[0011]

ClaimsFourThe communication device described is a claim.ThreeDescription
In the communication device ofFor wireless terminals with residence time q
Value of the transmission data is the same value as q, t [y] (where y = 1,2,
3, ... n) is newly input to the buffer corresponding to
(B) Data belonging to the same connection as the transmission data
If there is a buffer containing
Largest ofvaluet [y]Corresponded toIn the buffer,
There exists a positive integer k such that kp ≦ (q−t [y]) <(k + 1) p.
When I am there,Positive integerDo not change k'from 0 to k-1
Gara (t [y] + (k'-1) p, t [y] + k'p]
Value betweenCorresponded toOf the connection in the buffer
Calculate the total amount of data to be transmitted, and cycle the connection.
From the transmission rate that can be sent in the wireless section at p,
The value obtained by subtracting the sum is a, and the value of t [y] + k'pAgainst
RespondedLet b be the free space in the buffer, and a and
The newly arrived transmission data is t
[y] + k'p valueCorresponded toTyping in the buffer
(B) On the other hand, it belongs to the same connection as the transmission data.
If there is no buffer containing data that
There is a positive integer k such that (k + 1) p ≦ q <(k + 2) p
WhenPositive integerWhile changing k'from 1 to k in order,
Transmission that can be transmitted in the wireless section in the period p
The rate is a and the value of k'pCorresponded toIn the buffer
The free space to be set is b, within the range not exceeding a and b,
The value of k'p for the newly arrived transmission dataCorresponded toBa
I'll enter it in the table. For example, enter a new buffer
The transmission data for wireless terminals that are
Data that has and belongs to the same connection as the transmission data
If there is a buffer containing
In the buffer having the maximum value of t [y], kp ≦ (q
If there exists a positive integer k such that −t [y]) <(k + 1) p,
Then, changing k ′ from 0 to k−1 in order (t [y] +
(K'-1) p, t [y] + k'p]
Total amount of transmission data of the connection in the buffer
And the connection is in the wireless section in the cycle p.
The transmission rate that can be sent minus the total value
a and empty in the buffer with a value of t [y] + k'p
Capacity is b, and a new capacity is used as long as it does not exceed a and b.
The received transmission data is buffered with a value of t [y] + k'p
And then complete the procedure if k'is k.
As a result, if the transmission data could not all be accommodated,
If so, enter the rest into a buffer with a value of q, and
All newly arrived transmission data is input to the buffer on the way
If so, the process ends at that point, while the transmission data
Buffer containing data belonging to the same connection as
If there is no key, (k + 1) p ≦ q <(k + 2) p.
If there is a positive integer k, change k'from 1 to k in order
While the connection is sent in the wireless section in cycle p
A buffer with a possible transmission rate of a and a value of k'p
The free space in is defined as b, and the range does not exceed a and b
Then, the newly arrived transmission data is stored in the buffer with the value of k'p.
Enter in this step and end when k'is k in this procedure
As a result, all the transmission data could not be accommodated
In this case, enter the rest into a buffer with the value of q,
On the way, all newly arrived transmission data are put in the buffer.
If it receives a force, the process will end at that point.
The transmission data is written to the file.

[0013]

The communication apparatus according to a fifth aspect is the communication apparatus according to the third aspect , wherein the free capacity of the buffer is the amount of data that can be transmitted during a residence allowable time corresponding to the buffer. , A value obtained by subtracting the amount of data currently accumulated in the buffer and the amount of data currently accumulated in the buffer having a corresponding smaller allowable residence time than the buffer. For example, the buffer having the value of t [1] has a value obtained by subtracting the amount of data currently stored in the buffer from the amount of data that can be transmitted during the period t [1] as a free buffer capacity, The buffer having the value of t [y] (y = 2,3, ..., qmax / t [1]) has the above-mentioned t [z] (z = Buffer capacity management is performed such that the value obtained by subtracting the total amount of data already stored in the buffer having the value of 1, ..., Y) is used as the free buffer capacity.

According to a sixth aspect of the present invention, there is provided a communication device in which a retention time of transmission data from a wireless terminal for a new call is longer than a period of exchanging wireless frames with the wireless terminal, and an existing connection and If the total line output rate of the new call is less than or equal to the output line rate, the call is accepted, and if it is more than this, the call is rejected, and the allowable retention time of the transmission data from the wireless terminal for the new call is If it is smaller than the cycle of wireless frame exchange between the existing connections, the total line output rate of all connections and new calls whose residence time limit is less than the residence time limit of transmission data from the wireless terminal If the amount of data to be output within the allowable residence time at that rate is less than or equal to the amount of data that can actually be output to the line within that time, the call is accepted. Give performs refuse call reception control call when the above. For example, in a system in which at least one is used for communication between wireless terminals using the ATM adaptation layer type 2, the transmission and arrival cycles of a wireless frame, which is a unit of data transmission between the wireless terminal and the wireless base station, are set. Let q [x] (X = 1,2,3, ..., m) be the residence time allowed in the wireless base station for the transmission data from the wireless terminal for each of the p and m types of applications, and a new call arrives. If q is p or more, where q is the residence allowable time of the transmission data from the wireless terminal in the wireless base station,
Accept the call if the sum of the line output rates of all m types of applications and new calls is less than or equal to the output line rate, and reject the call if the line rate is higher than the line rate, while q is less than p In this case, find the total line output rate of all new applications and all of the m types of applications whose residence time is less than or equal to q, and determine the actual amount of data to output during the period of q at that rate during the same period. If the amount of data that can be output to the ATM line is less than or equal to, the call is accepted, and if not, the call is accepted.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of a communication system according to an embodiment of the present invention. As shown in the figure, the wireless terminal 1 moves and communicates with the wireless base stations 2 in the vicinity thereof, while the plurality of wireless base stations 2 are connected to the exchange 3 and the ATM line 4. AT at the end of exchange 3
Various public or private networks such as M network, N-ISDN, PSTN are connected.

Generally, in the wireless section 7, the transmission data is sent in a fixed length frame called a wireless frame and is sent.
As shown in FIG.
, And a plurality of radio frames 5 arrive at almost the same time. For example, in the CDMA technology, since the difference in data is recognized by the difference in code using the same frequency, the radio frames from different radio terminals 1 are almost synchronized due to the necessity of synchronization between codes. Therefore, as a characteristic of the data that arrives, a maximum number of wireless frames that burst in a fixed cycle arrive from the wireless terminal 1 to the wireless base station 2.

Further, as shown in FIG. 3, similarly, the radio frame 6 transmitted from the radio base station 2 to each radio terminal 1 is also transmitted at the same cycle as the arriving radio frame 5. Therefore, the transmission data also appears in bursts at regular intervals. The transmission / reception cycle of the wireless frames 5 and 6 is
For example, in wideband CDMA, it takes about 10 ms,
In this case, the amount of data accommodated in one frame is 640 bits even with 64 kbps traffic.

Generally an application, eg data,
The maximum value of the allowable delay is determined depending on the audio, video, etc., and it can be assigned to each configuration shown in FIG. Specifically, the delay until data transmission in the wireless terminal 1, the delay in the wireless section 7, the reception delay in the wireless base station 2, the delay for transmitting from the wireless base station 2 to the exchange 3, the exchange 3 , A delay for transmitting from the exchange 3 to the wireless base station 2, a processing delay for receiving from the exchange 3 at the wireless base station 2, and a delay for transmitting from the wireless base station 2 to the wireless terminal 1. , Delay in the wireless section 7, reception delay of the wireless terminal 1, and so on.

Here, as a first embodiment, the control of delay when the radio base station 2 transmits to the exchange 3 will be described, and as a second embodiment, the exchange 3 will direct to the radio base station 2. Control of delay at the time of transmission will be described, and as a third embodiment, call admission control as a premise for enabling these delay controls will be described.

(First Embodiment) FIG. 4 is a diagram showing the configuration of the radio base station 2. As shown in FIG.
Is a receiving unit 8 for reproducing a signal received from the wireless section 7 via the antenna, a packetization unit 9 for assembling the reproduced signal (radio frame) into a packet of a predetermined format, and temporarily accumulating the assembled packet, Buffer unit 10 to be loaded on ATM cell, ATM output from the buffer unit 10
It has an ATM interface unit 11 for sending cells to the ATM line 4.

FIG. 5 is a diagram showing the operation of the packetizing section 9.

As shown in the figure, the plurality of wireless frames 5 transmitted from the wireless terminal 1 are the information packets 12 first.
Be fixed by. One wireless terminal 1 has a plurality of wireless frames 5
, The wireless packet 5 is combined to complete one information packet 12. That is, the information packet can have a variable length.

The information packet 12 is packetized into an AAL type 2 packet 13. Regarding packetization, first of AAL type 2, SSCS (Service
Specific Convergence Subl
sequencer (SN) and C as needed
Turn on RC. And CPS (Common Par)
t Sublayer), it is divided into 45 octets and a header H of 3 octets is added.
The header H of 3 octets is similarly created for the fraction.

Here, the buffer section 10 has a plurality of buffers 10a, 10b, 10c ... Having different capacities. The CPS packet 13 is stored in the buffers 10a, 10b, ... According to the respective delay characteristics. The buffers 10a, 10b, ... Are shown as logically separate in FIG. 5, but of course they may be physically shared memories.
Input / output is performed according to the FIFO rule in each of the buffers 10a, 10b, .... Then, the buffers 10a, 10
In accordance with the transmission priority from b, ...
Data is read from 0b, ..., Mapped to ATM cells, and sent to the ATM interface unit 11.

There is a problem of where to define the allowable staying time of each transmission data. The end is the buffer 10a,
It can be said that the transmission data is read from 10b, ... And mapped to the ATM cell. On the other hand, the start time of the dwell time is, for example, a method that starts when each radio frame is received in a certain cycle and an information packet is constructed from the frame, a method that starts when an AAL packet is constructed, There is also a method of starting when the first AAL packet is put into the buffers 10a, 10b ,. In this example, AAL type 2 CPS
After packetization is completed, the first packet is buffered 10
a, 10b, ... is the start time when starting to input,
However, it can be realized with almost no change in other cases.

In the following, the operation of input to the buffers 10a, 10b, ... And output of the buffers 10a, 10b ,.

Assuming some applications in the long term, for each application,
It is necessary to define the above residence allowable time. For example, application A has q [1], application B has
Is q [2], and so on. If there are m types of applications now, there will be m types of q [x], including those with the same value.

As the output policy, it is necessary to put out the one with the shortest residence time first, so put it in a separate queue for each q [x], and output from the one with the smallest q [x] value. Will be done. Therefore, the buffers 10a, 10
.. are marked, the arrived data are input to the buffers 10a, 10b, ... With the corresponding marks, and the sending order between the buffers is controlled by comparing the marks of the buffers 10a, 10b. To use.

Regarding the method of marking, it is easiest to make it coincident with the value of the allowable residence time, so that will be used. That is, the arrived transmission data is stored in the buffers 10a, 1 in which the retention time q [x] of the user is written.
0b, ... will be input.

However, the value of q [x] is often much larger than the arrival period p of the radio frame. For example, as shown in FIG. 6, assuming that the allowable retention time of the transmission data A arriving at a certain time is 20 ms, and the allowable retention times of the transmission data B and C arriving 10 ms later are 5 ms and 15 ms, respectively, Although the data B arrives later, the data B must be output to the ATM line first, and the transmission data C has the allowable staying time shorter than the transmission data A, but the transmission data A
Will be output later than.

In order to enable the flexibility of the sending order with respect to such an arrival order, each buffer 10
It is necessary to change the value of the allowable residence time described in a, 10b, ... at any time. That is, the transmission data having the residence time of q [x] at a certain time is written in each of the buffers 10a, 10b, ... Taking advantage of the fact that the permitted time gradually decreases as time passes. Decrease the value of allowable residence time by a fixed value.

In the case of the present embodiment, new transmission data arrives only every fixed period p, so the allowable stay time can be updated every p.

A concrete example is shown in FIG. Here, for simplification, only two types of applications A and B are assumed, and it is assumed that the application A has a staying allowable time of 5 ms and B has a staying allowable time of 50 ms. Further, the cycle p of arrival of the radio frame is 1
It shall be 0 ms.

It is assumed that the transmission data A1 of the application A and the transmission data B1 of the application B arrive at a certain time. Allowable residence time for A1 is 5ms, so 5ms
Is input to the buffer 701 having the display. On the other hand, B
Since the residence allowable time of 1 is 50 ms, it is input to the buffer 702 indicated by 50 ms.

It is assumed that the transmission data A2 of the application A and the transmission data B2 of the application B arrive when the period p, that is, 10 ms has elapsed. Since the allowable residence time of A1 is shorter than the period p, A1 has already been output to the ATM line. As a result, the buffer 701 is empty and the display of 5 ms is displayed.
2 is input to the buffer 701. On the other hand, the buffer 70
2 may still have B1 remaining, and since the allowable residence time is obviously shorter than the next incoming B2,
For the purpose of distinction, the display is changed to 50 ms, which is a certain allowable residence time, and 40 ms obtained by subtracting 10 ms from the period p. Then, a buffer 703 having a display of the staying allowable time of 50 ms is newly prepared, and B
2 is entered there.

Further, in the next cycle, the transmission data A3 of the application A and the transmission data B3 of the application B are transmitted.
Suppose that arrived. Since A2 has already been output and is empty in the buffer 701, the problem of order control does not occur. Therefore, A3 is input to the buffer 701. The buffer 702 rewrites the value from 40 ms to 30 ms, and the buffer 703 rewrites the value from 50 ms to 40 ms. Then, a new buffer 70 having a value of 50 ms
Prepare 4 and put B3 there.

When expanded in this way, in addition to the buffer 701 having a value of 5 ms, 10 ms, 20 ms, 30
It can be seen that buffers having respective values of ms, 40 ms, and 50 ms are required. The 10ms buffer is
In the next cycle, the contents will definitely be empty, so it will be 50m again.
It can be reused by rewriting it as s.

Therefore, in this example, as shown in FIG.
Buffer 701 having a value of 5 ms, 50 ms with a maximum value of 50 ms → 40 ms → 30 ms → 20 ms → 10 ms →
5 kinds of buffers whose value changes to 50 ms and the value changes to cyclic, and the values are different at the same timing.
It can be seen that 6 types of buffers of 02 to 706 are required.

Generalizing the above, the arrival period of the wireless frame 5 which is the unit of data transmission from the wireless terminal 1 is p,
The allowable residence time of the transmission data from the wireless terminal 1 in the wireless base station 2 is q [x] (X
= 1,2,3, ..., m), q [x] for each q [x]
And all positive values obtained by subtracting p from q [x] one or more times, with the exception of overlapping ones, t [y] (y
= 1,2,3, ..., N), and n buffers having each t [y] as the value of the allowable residence time are created.

The transmission data from the wireless terminal 1 is put in the buffer 10 having the same t [y] value as the staying allowable value, and t
The data is sent to the network side in order from the buffer 10 having the smallest value of [y].

The value of t [y] in the buffer 10 is updated every period p at which the next data from the wireless terminal 1 arrives.

Buffer 1 having a value of t [y] larger than p
0 is replaced by the value of t [y] −p, and t [y] below p
The buffer 10 having the value of has the same value as the retention allowable value of the application among t [y] and t [y] to which p is added one or more times, and the maximum value of t [y] Will be replaced by the value.

For data transmission, the buffer 10 having the replaced value is t [1], t [2], ...
When it is turned on, buffer 10 with the value of t [1]
It is realized that the contents are sequentially output to the ATM line 4.

Next, the buffer capacity required from the output line capacity will be described.

The ATM line 4 is generally 155 Mbps or the like, but when AAL type 2 is used, a line with a relatively narrow band, for example, 6 Mbps or 1.5 Mbps is often used. Here, it is assumed that 1.5 Mbps is used.

A 1.5 Mbps line is exactly 1.53
6 Mbps, one for each 125 μs frame
It contains 93 bits. Since 1 bit among them is F bit, the ATM cell can accommodate 192 bits (24 octets).

As an example, as shown in FIG. 9, the allowable residence time is 5
Assuming there are only two buffers of 10 ms each, for 5 ms there are 40 times 24 octets available for 960 octets. An ATM cell is inserted in the ATM cell. The ATM cell has a header of 5 octets of 53 octets, and 1 octet of the payload is used for accommodating an AAL type 2 CPS packet. About Octets 47
Can be used for each octet. Then, in 960 octets, 53 octets are 18 and the remainder is 6 octets. Therefore, the number of octets that can be used in 5 ms is 846 octets or more and 852 octets or less. Here, 846 octets are given to a buffer having a value of 5 ms, assuming that 846 octets is a band that can be used by the user as a constant value. That is, as shown in FIG. 9A, the buffer 901 having a value of 5 ms is always 84
If up to 6 octets are available and there are currently 500 octets in the buffer, 846-50
At 0, 346 octets become a free area.

On the other hand, in the case of 10 ms, the free area changes depending on the state of 5 ms. 1920 octets can be used for 10 ms, and considering the overhead due to the ATM cell similar to the above, in the maximum case, the capacity of the buffer 902 having a value of 10 ms is 1 as shown in FIG. 9B.
It will be 698 octets. However, as for the free capacity, if 700 octets are used in the buffer 902, 500 octets from 1698 octets to 700 octets and 5 ms are used.
Both octets are subtracted, leaving 498 octets free. As described above, the size of the free area is affected by the presence / absence of a buffer having a residence allowance time smaller than that of the buffer.

If this is generalized, the values of the allowable residence time added to the buffer are t [1], t [2],
..., t [n], the buffer with the value of t [1] is
It has a value obtained by subtracting the amount of data currently stored in the buffer from the amount of data that can be transmitted during the period t [1] as free space, and has a value of t [y] (y = 2 to n). The buffer is t [z] from the amount of data that can be sent during the period t [y].
A value obtained by subtracting the total amount of data stored in the buffer having a value of (z = 1,2,3, ..., y) is provided as the free buffer capacity.

(Second Embodiment) FIG. 10 is a diagram showing the structure of the exchange 3. As shown in the figure, the exchange 3 has a switch 14 for exchange, a packetization unit 15 that assembles the transmission data distributed by the switch 14 into packets of a predetermined format, temporarily stores the assembled packets, and
It has a buffer section 16 to be placed on the M cells and an ATM interface section 17 for sending out the ATM cells output from the buffer section 16 to the ATM line 4.

FIG. 11 is a diagram showing the operation of the packetizing section 15.

Here, unlike the first embodiment, the transmission data from the network does not arrive regularly. Therefore, as shown in FIG. 11, the information packet output from the switch unit 14 is F
The data is put in the IFO-like buffer 18 and sequentially extracted from there.

The extracted information packet 19 is processed by AAL type 2 CPS by the same procedure as in the first embodiment.
It is in the form of a packet 20.

Here, the buffer section 16 has a plurality of buffers 16a, 16b, 16c ... Having different capacities. Then, the CPS packet 20 is stored in the buffers 16a, 16b, ... According to the respective delay characteristics. At this time,
The difference from the first embodiment is that the AAL type 2 packet 20 generated from the same information packet may be put in different buffers 16a, 16b, .... In the following, the principle here and the buffers 16a, 16
The values of b, ... Will be described.

In the second embodiment, the arrival of the information packet 19 can be considered at all timings. Therefore, each time each information packet 19 arrives, the buffers 16a, 16
Buffering must be performed while changing the value of the allowable residence time given to b, ... In principle. It is impossible to update every cycle p as in the first embodiment. However, it is difficult to implement it strictly, so some rounding error is allowed.

The residence time allowed at the interface indicated by the application from the exchange to the radio base station is q [x] (X = 1, 2,
3, ..., M), a unit t [1] is determined from this value. The best way to determine t [1] is to take the greatest common divisor of m q [x]. For example, the period p is 10
If it is ms, it is desirable in calculation that it is also a divisor thereof. That is, generally, it is settled at a place such as 1 ms or 2 ms. Here, consider the case where t [1] is 1 ms.

It is necessary to change the value of each buffer every time t [1]. Therefore, let qma be the largest of q [x].
Let x be all buffers with multiples of t [1] up to qmax. Therefore, the number of buffers is qmax /
It becomes t [1].

Each buffer changes from t [y] to t [y-1] every time t [1]. Here, t [y] corresponds to y * t [1]. However, since the contents of the buffer having the value of t [1] will be empty, change it to qmax. That is, as shown in FIG. 12, the maximum value is qmax, and the threshold value is changed to t [1] by t [1] every t [1], and at the same timing, the values are different qmax / t [1]. It turns out that this requires buffers.

Next, the buffer capacity required from the output line capacity will be described. ATM line is 155Mbps
However, when using AAL type 2, a line with a relatively narrow band, for example, 6 Mbps or 1.5 Mbps is often used. Here, it is assumed that 1.5 Mbps is used.

A 1.5 Mbps line is exactly 1.53
6 Mbps, one for each 125 μs frame
It contains 93 bits. Since 1 bit among them is F bit, the ATM cell can accommodate 192 bits (24 octets).

Assuming that there are only two buffers having a residence time limit of 1 ms and 2 ms, 192 octets can be used in 1 ms, which is eight times 24 octets. An ATM cell is inserted in the ATM cell. The ATM cell has a header of 5 octets of 53 octets, and 1 octet of the payload is used for accommodating an AAL type 2 CPS packet. About 47 octets can be used for each octet. Then, in 192 octets, 53 octets are 3 and the remainder is 33 octets. Therefore, the number of octets that can be used in 1 ms is 168 octets or more 17
It is 4 octets or less. Here, as a constant value, 16
Assuming 8 octets is the bandwidth that the user can use,
A buffer with a value of 1 ms gives 168 octets. That is, as shown in FIG. 13A, the buffer 1301 having a value of 1 ms is always usable up to 174 octets, and if 100 octets are currently stored in the buffer 1301, 74 octets are free in 174-100. Becomes

On the other hand, in the case of 2 ms, the free area changes depending on the state of 1 ms. 384 octets can be used in 2 ms, and in consideration of the overhead due to the ATM cell similar to the above, in the maximum case, the capacity of the buffer having a value of 2 ms is 336 octets. However, FIG.
As shown in (b), if 200 octets are used in the buffer 1302 as the free space of the buffer 1302, the buffer 1302 has 20 bytes from 336 octets.
By subtracting both 0 octet and 100 octet used in the buffer having a value of 1 ms, 36 octet becomes an empty area. As described above, the size of the free area is affected by the presence / absence of a buffer having a residence allowance time smaller than that of the buffer.

Generalizing this, the values of the allowable residence time added to the buffer are t [1], t [2],
..., t [n], the buffer with the value of t [1] is
It has a value obtained by subtracting the amount of data currently stored in the buffer from the amount of data that can be transmitted during the period t [1] as free space, and has a value of t [y] (y = 2 to n). The buffer is t [z] from the amount of data that can be sent during the period t [y].
A value obtained by subtracting the total amount of data stored in the buffer having a value of (z = 1,2,3, ..., y) is provided as the free buffer capacity.

As described above, since the information packet input in FIG. 11 is passing through the network such as the public network, delay fluctuation occurs. In addition, a wired terminal may output a large information packet regardless of the structure of the wireless frame of the wireless terminal 1.

If no measures are taken with respect to these fluctuations and the size of the information packet, the radio base station 2 on the receiving side will have an excessive amount of buffer retention. In the wireless base station 2, the wireless terminal 1
On the other hand, since it has a characteristic that communication is performed through the wireless section 7 whose maximum value is determined every fixed period p, burst traffic in the wired section cannot be absorbed. In addition, causing such retention means, on the contrary, that there is transmission data that cannot be passed by that amount, and the unbalanced state eventually leads to a decrease in the throughput of the entire system. It can happen.

Therefore, at the output side of the exchange 3, it is necessary to consider a queuing method to a buffer that alleviates the burstiness of the transmission data sent to the radio base station 2. However, there is an assumption that the allowable residence time in this part must be observed.

The principle is as shown in FIG.

That is, when the transmission data of a certain connection arrives (step 1401), it is checked whether or not the staying allowable time q is longer than the cycle p (step 1).
402). If q is less than or equal to p, it is put in a buffer having q as its value (step 1403). If q is larger than p, the buffer in which the connection is queued last is searched (step 1404).

If there is such a buffer and the difference between the value of the residence time limit q'of that buffer and the value of the residence time limit q of the transmission data is less than p (step 140)
5) All the transmission data that have arrived this time are unconditionally put in a buffer having a value of q (step 1403).

If the difference between the value of q'and q is greater than or equal to p, first, the transmission data of the connection queued in the buffer having the value in the section of (q'-p, q '). The sum s of the quantities is obtained (step 1406).
Then, the minimum value of the value a obtained by subtracting the total amount from the amount of transmission data passing through the wireless section of the connection and the free area in the buffer is compared, and the smaller one is set to b (step 1407). ). Next, within the range not exceeding b,
The arriving transmission data is sequentially input to the buffer for each CPS packet (step 1408). However, (numeral 1, numeral 2) means that it is greater than numeral 1 and less than numeral 2.

Next, the difference between the value of q'and q is k * p (k>
If 1) or more (step 1409), the transmitted transmission data arrives for each CPS packet within a range that does not exceed the free area in the buffer having the value of q '+ (k-1) p in order from the smallest value of k. Input to the buffer in order (step 1410).

If all of the arrived transmission data are completed in the process of inputting to those buffers (step 1411), this work is finished at that point, and vice versa. If there are remaining transmission data that arrive as a result of the attempt, they are all input to the buffer having the value of q (step 1403).

On the other hand, when there is no buffer in which the connection is queued (step 1404), and q is p or less (step 1412), all the transmission data that have arrived this time unconditionally take the value of q. It is put into the buffer it has (step 1403).

If the value of q is greater than or equal to k * p (k> 1) (step 1413), the free area in the buffer having the value of (k-1) p is exceeded in order from the smallest value of k. Within the range that does not exist, the transmission data that has arrived is sequentially input to the buffer for each CPS packet (step 141).
4).

Then, if all of the arrived transmission data are completed in the process of inputting to those buffers (step 1411), this work is finished at that point, and vice versa. If there are remaining transmission data that arrive as a result of the attempt, they are all input to the buffer having the value of q (step 1403).

In such a buffer input method, a kind of shaping is performed so that the transmission capacity in the wireless section is not exceeded for the period p when viewed in a certain section. In addition, queuing is performed as fairly as possible within that range, and transmission data that arrives late can be input to a buffer that is output first.

By doing so, it is possible to suppress an increase in the buffer in the radio base station due to the inability to output in the radio section. Further, when the arrival arrives with a delay, it is possible to increase the transmission efficiency by reducing the number of transmissions in the radio section with no space as it is. Furthermore, by making effective use of the wireless section, it is possible to eliminate abnormal retention for each connection, suppress delay, and suppress packet discard.

(Third Embodiment) As a third embodiment, call admission control for successfully performing the delay control in the first and second embodiments will be described.

In the case of an ATM network, call admission control is essentially Q. It is common to use a signaling protocol such as 2931. However, A
In AL type 2, not one VC level but one V
Since it is necessary to take into consideration the case where a plurality of users are multiplexed in C, a method called ANP is used in consideration of the existing signaling method. However, since ANP corresponds to signaling at the AAL level, a simple procedure is desirable. Here, a relatively simple method is described.

In the first and second embodiments, in the case where data overflows from the buffer,
I didn't say anything. When a buffer overflow occurs, the transmission data is discarded, but it is important to devise a call acceptance method so as to avoid it.

Therefore, first, the case of the first embodiment will be verified. As an example, the arrival period p of the radio frame is 10 ms,
The allowable residence time is 30 ms for application A, 20 ms for application B, and 10 ms for application C. When the transmission data of applications A, B, and C arrive at a certain time, 30
At first glance, they appear to be irrelevant because they are input to different buffers with dwell delay time values of ms, 20 ms, 10 ms.

However, it is assumed that the transmission data of the applications A, B and C arrive in the next cycle. The transmission data of the application B is written in a buffer having a residence time of 20 ms, and this buffer contains the transmission data of the application A that arrived last time. This is because the buffer whose residence time was 30 ms at the previous time has one cycle, and therefore has a value for that cycle, that is, a value of 20 ms obtained by subtracting 10 ms.

Similarly, in the next cycle, this time, 10 m
The transmission data of the application C that has arrived this time and the application B that has arrived last time are stored in the buffer having the value of s.
Transmission data and application A that arrived the last time
Will be transmitted. It is not known whether a buffer overflow will occur unless the state of the buffer immediately before being sent out is taken into consideration.

Further, as another argument, the free capacity of each buffer is variable depending on how much transmission data is buffered in the buffer having a residence time allowed to be smaller than that buffer. Specifically, as described above, the free capacity of the buffer having the value of t [1] is t
[1] The amount of data that can be sent during the period minus the amount of data that is currently buffered. The free space of the buffer having the value of t [y] (y = 2,3, ..., n) is t
From the amount of data that can be sent in the [y] period, the current t [z] (z = 1,
2,3, ..., y-1) is the total amount of data in the buffer. Therefore, it is necessary to consider not only the capacity of the buffer that is in the same buffer but also the free capacity of the buffer that has a smaller allowable residence time than the buffer.

Based on the above, when a new call arrives, let us consider a method of judging the admission of the call.

Now, as existing connections: -Connections A, B, and C: The transmission data amount in one frame is 80 octets, and the allowable retention time is 5 ms.-Connections D, E: The transmission data amount in one frame is 180 octets. The permissible time is 5 ms.-The transmission data amount in one frame of connection F is 25 ms and the transmission data amount in one frame is 25 ms.-The transmission data amount in one frame of connection G is 480 octets.

As described above, in call admission control, the judgment must be made by using a buffer shorter than the cycle p.
This is because the buffer having the value of 20 ms has the largest buffer capacity when it is rewritten to the value of 10 ms, and it is good if there is no buffer overflow at that time. If the period p is 10 ms in the above example, the first
There are two buffers with values of 5ms and 10ms as shown in the embodiment of. Therefore, it is assumed that a buffer having these two values is used for call admission control, and when a new call is admitted, the call is admitted if these buffers do not overflow, and the admission is rejected if an overflow occurs.

As described above, assuming a line of 1.5 Mbps, the maximum size of a buffer having a value of 5 ms is 846 octets. Also, a buffer having a value of 10 ms has a maximum of 1698 octets.

Now, it is assumed that the transmission data of the above connection is stored in these buffers. A to E
Up to is counted in a buffer with a value of 5 ms. On the other hand, since F and G are values larger than the period p, that is, 10 ms, they are all counted in the buffer having a value of 10 ms. As in the first embodiment,
The application F is actually input to the buffer having a value of 25 ms, and the value is rewritten to 5 ms after two cycles to enter the buffer having the allowable residence time of 5 ms, but this is a different count in call admission control. . This state is shown in FIG.

The AAL type 2 adds a 3-octet header every 45 octets. Application A,
In B and C, the transmission data is 80 octets, but a header for 6 octets is added to make it 86 octets in the buffer. Further, the applications D and E have an overhead of 12 octets and become 192 octets each. As a result, the buffer with a value of 5 ms is 84
The octet number of the AAL2 packet of each application is subtracted from 6 octets to obtain a free area of 204 octets.

The application F has 192 octets with a CPS header of 12 octets as in the case of D and E, and the application G has 11 CPS packets and thus has an overhead of 33 octets and becomes 513 octets. As a result, in the buffer having a value of 10 ms, a free area of 351 octets is obtained by subtracting the number of octets of all CPS packets of applications A, B, C, D, E, F, and G from 1698 octets.

From this, the following call admission determination is made.

(1) When the call has an allowable residence time of 5 ms In this case, the call is accepted if the transmission data of one radio frame is equal to or less than 204 octets, which is the free area of the buffer having a value of 5 ms, and rejected if it is larger than that. Will be done.

(2) When the call has a dwell time of 10 ms or more, the call is accepted if the transmission data of one radio frame is 351 octets or less, which is the free space of the buffer having a value of 10 ms, and rejected if it is larger than that. To do.

Here, it is assumed that a call of which transmission data of one radio frame is 300 octets has originated, for example, with a residence time of 25 ms. As mentioned above, this call actually goes into a buffer with a value of 5ms, so from that point of view, the 5ms buffer only has 204 octets to spare, so the acceptance is rejected. However, since this call has a dwell time of 25 ms, it is completely acceptable to change this to 20 ms on the network side. If so, 10m in 20ms
Since it enters the buffer having the value of s, in this case, there is a margin of 351 octets, so it will be accepted.

Therefore, regardless of the problem of buffering in the first embodiment, if the call admission determination is made assuming that a device having a residence time of more than 10 ms enters the buffer of 10 ms, more calls will be output. I know that I can accept. According to the first embodiment when received in this way, 5 m in each cycle.
Since there is still room after outputting all the data from the buffer with the value of s and the buffer with the value of 10 ms, 1
A maximum of 351 octets of data can be read from the buffer having a value of 5 ms. By reading the buffer having the value exceeding the cycle p first, the buffer having the value of 15 ms becomes 5 m in the next cycle.
When changed to the buffer with the value of s, the remaining 5m
This means that the amount of data can be output during s.

The generalization of this result is as follows.

The transmission and arrival cycle of a radio frame, which is a unit of data transmission between the radio terminal and the radio base station, is p, and the retention of transmission data from the radio terminal in the radio base station for each of m types of applications is permitted. Let q [x] (X = 1,2,3, ..., m) be the time, and let q be the allowable stay time of the transmission data from the wireless terminal in the wireless base station when a new call arrives.

When q is p or more, the call is accepted when the sum of the line output rates of all m types of applications and new calls is less than or equal to the output line rate,
If it is higher than the line rate, the call is rejected.

On the other hand, when q is smaller than p, the total line output rate of all new applications and all of the m types of applications whose residence time is q or less is calculated, and output in the period of q at that rate. Call admission control is performed in which the call is admitted if the amount of data desired to be transmitted is equal to or less than the amount of data that can actually be output to the ATM line during the same period, or rejected otherwise.

By such call admission control, the radio base station can perform buffering without fear of buffer overflow. Since this method is relatively simple, it can be sufficiently used as an ANP method.

Also in the case of going from the exchange to the radio base station as in the second embodiment, as long as the call admission control is performed by the above-described method, the buffer overflow does not occur unless there is delay variation. Further, since the traffic with a large delay is devised so that it can be transmitted after being smoothed in each cycle by the method as in the second embodiment, the probability of buffer overflow can be suppressed sufficiently small.

However, this does not hold when the traffic from the exchange to the radio base station is larger than the traffic in the reverse direction, such as broadcast type traffic or asymmetrical traffic. When such an asymmetrical connection is included, it is solved by using the larger transmission band as the parameter of the above-mentioned call admission control.

[0105]

As described above, according to the present invention as set forth in claims 1 and 2 , the residence time of an appropriate value for the traffic arriving in bursts in the form of radio frames at regular intervals A buffer having the following is prepared, each transmission data is buffered according to the parameter of the allowable stay time, the allowable stay time of the buffer is appropriately replaced at regular intervals, and then the buffer with the shorter allowable stay time is sequentially transferred to the exchange. By outputting to the ATM side, it is possible to perform the ATM type 2 priority control considering the delay time for each application.

Further, according to the present invention as set forth in claims 3 to 5 , the fluctuation of the traffic to one wireless terminal within the range in which the residence time allowed in the exchange is held, and the characteristics of the wireless line which is the last hop are taken into consideration. By suppressing, it is possible to realize relatively fair transmission control for each connection, and as a result, it is possible to suppress the residence time in the part from the wireless base station to the wireless terminal and also to reduce the buffer amount in the wireless base station. it can.

Further, in the present invention as defined in claim 6, the admission allowable time of the received connection in the radio base station is controlled by performing the call admission control so that the buffer overflow does not occur by utilizing the characteristics of the present invention. Can be suppressed to the specified parameter, and
This also works for the second smoothed traffic,
It is possible to suppress an increase in residence time allowed in the exchange.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a communication system according to an embodiment of the present invention.

FIG. 2 is a diagram showing a state of a wireless frame from a wireless terminal to a wireless base station.

FIG. 3 is a diagram showing a state of a wireless frame from a wireless base station to a wireless terminal.

FIG. 4 is a diagram showing a configuration of a radio base station shown in FIG.

5 is a diagram showing an operation of the packetization unit shown in FIG.

6 is a diagram showing a state of retention of transmission data in a buffer unit shown in FIG.

FIG. 7 is a diagram showing updating of an allowable residence time in the buffer unit shown in FIG.

FIG. 8 is a diagram showing updating of an allowable residence time in the buffer unit shown in FIG.

FIG. 9 is a diagram for explaining a buffer capacity required from an output line capacity.

10 is a diagram showing a configuration of the exchange shown in FIG.

11 is a diagram showing an operation of the packetizing unit shown in FIG.

FIG. 12 is a diagram showing updating of an allowable residence time in the buffer unit shown in FIG.

FIG. 13 is a diagram for explaining a buffer capacity required from an output line capacity.

FIG. 14 is a flowchart showing a queuing method for buffering to mitigate the burstiness of transmission data sent to a wireless base station on the output side of an exchange.

FIG. 15 is a diagram for explaining a buffer capacity calculation for call admission determination.

[Explanation of symbols]

1 wireless terminal 2 wireless base stations 3 exchanges 4 ATM line 7 wireless sections

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI H04Q 7/26 7/30

Claims (6)

(57) [Claims] 1. Storage of transmission data from a wireless terminal,
A plurality of buffers corresponding to different residence allowable times and the buffer corresponding to the residence allowable times of the transmission data
In order from the means for accumulating the transmission data, and the corresponding buffer having a smaller residence allowable time,
Means for sending the accumulated transmission data to the network side
If, the corresponding <br/> residence time allowed in the buffer in which to correspond to the large residence time allowed than the period in which transmission data arrives from the radio terminal, and means for cyclically changed for each said cycle by the cycle minutes A communication device comprising: 2. The communication device according to claim 1, wherein the amount of data currently accumulated in the buffer is calculated from the amount of data that can be sent out of the free space of the buffer during the retention allowable time corresponding to the buffer. And more compatible than the buffer
That the residence time allowed communication apparatus characterized by a value obtained by subtracting the amount of data currently stored in a small buffer. 3. Storage of transmission data from the network
Corresponding to the allowable residence time that is an integral multiple of the predetermined time unit
A plurality of buffers, and the buffer corresponding to the retention time of the transmission data
In order from the means for accumulating the transmission data, and the corresponding buffer having a smaller residence allowable time,
And means for delivering the stored transmission data to the radio terminal, the corresponding <br/> residence time allowed in the buffer in which to correspond to the large residence time allowed than the period in which transmission data arrives from the radio terminal, the period communication apparatus characterized by comprising a means for cyclically changed by the periodic minutes each. 4. The communication device according to claim 3, wherein the transmission data for a wireless terminal having a residence time q is q
Corresponding to the value t [y] (where y = 1,2,3, ... n)
In the case where there is a buffer newly input to the buffer, and (a) there is a buffer containing data belonging to the same connection as the transmission data, in the buffer corresponding to the maximum value t [y] in the buffer,
When there exists a positive integer k such that kp ≦ (q−t [y]) <(k + 1) p, the positive integer k ′ is sequentially changed from 0 to k−1 (t [y] + (k′−1)). p, t [y] + k'p] section corresponding to the value of the section, the total value of the transmission data amount of the connection in the buffer is calculated. The value subtracted is a, and the value of t [y] + k'p is paired
Let b be the free space in the buffer that has been made to respond , and set the newly arrived transmission data to t without exceeding a and b.
Input to the buffer corresponding to the value of [y] + k'p. (b) On the other hand, when there is no buffer containing data belonging to the same connection as the transmission data,
When there is a positive integer k such that (k + 1) p ≦ q <(k + 2) p, the transmission rate at which the connection can be transmitted in the wireless section in the cycle p is a while changing the positive integer k ′ in order from 1 to k, and k 'The free space in the buffer corresponding to the value of p is set to b, and within the range not exceeding a and b,
A communication device, characterized in that newly arrived transmission data is input to a buffer corresponding to a value of k'p. 5. The communication device according to claim 3 , wherein the amount of data currently accumulated in the buffer is determined from the amount of data that can be transmitted from the free space of the buffer during the residence allowable time corresponding to the buffer. And more compatible than the buffer
That the residence time allowed communication apparatus characterized by a value obtained by subtracting the amount of data currently stored in a small buffer. 6. When the allowable retention time of transmission data from a wireless terminal for a new call is longer than the cycle of wireless frame exchange with the wireless terminal, the line output rate of an existing connection and a new call is If the total is less than or equal to the output line rate, the call is accepted, and if it is more than this, the call is rejected, and the allowable retention time of the transmission data from the wireless terminal for the new call is exchanged between the wireless terminal and the wireless frame. If the period is less than the cycle, the total line output rate of all connections and new calls for which the allowable stay time of the existing connections is less than the allowable stay time of the transmission data from the wireless terminal is calculated, and the allowable stay at that rate is calculated. If the amount of data to be output within the time is less than or equal to the amount of data that can be actually output to the line within the time, the call is accepted,
A communication device which performs call admission control for rejecting a call in the above case.