SE521606C2 - Method and circuit-switched, frame-based communication system for bandwidth-adapted use of communication link - Google Patents

Abstract

The present invention relates to methods for bandwidth adapted utilisation of a bandwidth restricted communication link between a first and a second node (11, 12) in a communication system, wherein a communication link (CL) has a total bandwidth Btot which cannot be exceeded. The invented method comprises inserting a determined bandwidth indicator for a specific sublink (SLk). All sublinks which are connected to the communication link (CL) have their specific bandwidth indicator. The sublinks are combined (41) within said total bandwidth Btot into a data stream, and the data stream including the sublink bandwidth indicator (BIk) in a certain fixed position in each sublink is transmitted (42) over said communication link (CL) to the second node (12). The bandwidth indicators (BIk) are received (43) and read (44) at said second node and the data stream is split (45) into the different sublinks according to the respective sublink data and the bandwidth indicator (BIk). The invention is also a circuit switched, frame based communication system (10) for bandwidth adapted utilisation of a bandwidth restricted communication link (CL) between a first and a second node (11, 12) in the system in accordance with the methods.

Description

20 25 30 U7 RJ ... A Ö \ CD O \ 2 to one of said two nodes. A first node comprises a multiplexer unit which multiplexes the data of the sublink according to a multiplexing algorithm for sequential transmission to the second node via a communication link to which the sublinks are connected. Each sublink addresses one of a group of sublink recipients. This node includes a demultiplexer unit which receives the sublink link data stream, divides it and distributes it to the correct sublink receiver in the same order as those multiplexed. For this reason, a distribution protocol for the transmission of data via the communication link must be designed.

However, different users and user groups have different needs for data transfer capacity_ Users can choose between different data services. A data service often generates data with a different data rate. data rates are used by different services. The ratio of two data rates can be two or three times or more. In some user groups the amount of services is with high data rates and in some such large user groups there are no users. Some user groups would therefore need high capacity sub-links only some need sub-links. and user groups low-capacity- However, as mentioned above, the protocol is designed the same bandwidth for all sub-links relationship for a given relationship: and user groups. This results in two main options, either low data rate, which can lead to a risk of congestion or high data rate for all sub-links, which means high costs.

Thus, there is a problem in a communication system in which the sub-links are dimensioned for services with the highest data rate. Sub-links that carry data generated by user groups with low data rate operation will thus, in order to carry a lot of padding information (dummy information), fill the unused space. In a commercial network, customers rent communication links on a transmission link and the customer has to pay for unused transmission capacity. The alternative with low-capacity sub-links has the effect that user groups can be excluded.

It is already known, see WO96 / 21999, that in a mobile radio system which transmits messages in a single interface, to provide a discrimination parameter which. can be used to discriminate between the frames belonging to different radio interfaces and signaling protocols, however, not to discriminate between different bandwidth requirements.

Disclosure of the Invention The present invention relates to a solution to the above-described cost and capacity problems.

An object of the invention is to provide flexible and lightweight. methods of adaptation. the bandwidth in a user group to the required bandwidth if the individual users in the user group need more or less sublink bandwidth for a longer period.

The above problems are solved by providing each of the sub-links with a bandwidth indicator and the communication system is provided with means for using the information from the respective bandwidth indicator.

According to one embodiment, the invention relates to a method for bandwidth-adapted use of a bandwidth-limited communication link between a first and a second node in a communication system. The system comprises means for transmitting and receiving sub-links, of digital information on the communication link. has a total bandwidth Bum that can not be exceeded. The invention comprises a step of allocating and combining said sub-links within the total bandwidth Bwt to a data stream, a subsequent step comprising a sub-link bandwidth indicator at a certain fixed position in each sub-link over said communication link to the second node and a step of reading the sublink bandwidth indicators at said second node and dividing the data stream on the various sublinks according to the indicators.

According to a second embodiment of the system, the invention is a circuit-switched, frame-based communication system which comprises means for bandwidth-adapted use of a bandwidth-limited communication link between a first and a second node in the system. The communication system includes means for allocation and. combination. of 'sub-links ~ inonl said total. bandwidth. BUM to a data stream, means for transmitting said data stream comprising a "sublink bandwidth indicator" at a certain fixed position in each sublink via said communication link to it and at this node means for the second node reading the sublink bandwidth indicators and dividing the data stream according to the various sublinkers. .

Advantages of this that the described invention is above the capacity problem can be solved. The sublink bandwidth is adapted to the needs of the user group to which it belongs. A further advantage is that the invention provides a flexible and easy method for adapting it. necessary. the bandwidth of a user group if said user group needs more or less sublink bandwidth for a longer period of time.

A further advantage is that the invention provides "a more cost and transmission efficient communication system. Brief Description of the Drawings For a better understanding of the present invention, reference is made here to the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. Fig. 1 shows a block diagram of two nodes and connected terminals in a communication system illustrating the method according to the invention; Fig. 2 shows a flow chart of an embodiment according to the present invention; Fig. 3 shows two different frame structures for transmission in the system according to Fig. 1 and i Fig. 4 shows a diagram illustrating the bandwidth requirements for three different sub-links in the system according to Fig. 1 and in which the method according to the invention is used.

Description of embodiments The invention will now be described in more detail with reference to Fig. 1 and Fig. 2.

The invention relates to a method and a device for traffic-adapted use of a bandwidth-limited communication link between a first and a second node in a communication system, which comprises means for transmitting and receiving digital information on sub-links, said communication link having the total bandwidth Bum. Each sublink carries data associated with a number of users. Fig. 1 shows a block diagram of a communication system 10 which has two nodes - a first node 11 and a second node 12 - and a communication link CL between them. The first node is considered as a main node comprising a control unit 13 for controlling the means and functions of the node 11. In addition to the control unit 13, the first node 11 comprises inputs 16 for a corresponding number of sub-links, a communication source unit 14, monitoring means 21, packing means 23, transmitting means 24 and allocating means 22.

To node 11 a number of generating units 15 and to node 12 a number of measuring units 31 are connected. A generator unit 15 communicates data information on a frame base via the communication link CL to a target unit 31. The nodes and units are separated by the dashed lines 18 and 32 and the communication link CL.

The first node 11, also called the main node, comprises at least two, but usually several, input ports 16. Each input port 16 is connected to a sublink generator 15. Each sublink generator 15 generates digital information and transmits the information on a sublink according to a sublink protocol.

The first node 11 comprises a source communication unit 14 with means for transmitting and receiving digital signals via an interface, which is shown by the dashed line 18 between the sublink generators 15 and the first node 11. Said means is selected depending on different parameters such as medium (e.g. air , line, etc.), coding, modulation, etc. The source communication unit 14 makes it possible to receive sub-links defined by means of different protocols.

According to the present invention, BI2, a bandwidth indicator BI1, .., BIk is assigned to each sublink to indicate the necessary bandwidth for the digital information transmitted via the sublink. The BIs can be allocated by means of the allocating means 22. In the present embodiment according to Fig. 1, however, the BIs are incorporated in the frame structure for each sublink already and from the beginning of the communication and sublink generator 15 as will be described in more detail according to Fig. 3. A plurality of sublink generators 15 belonging to the system 10 generate digital information soul transmitted on a plurality of sublinks SL which are transmitted to the various inputs 16 on the first node 11. The inserted bandwidth indicator BIk for a particular sublink thus provides information about the necessary bandwidth for reception in the receiving node 12. This necessary bandwidth is then less than if the bandwidth indicator had not been used, whereby a reduction of the bandwidth on the communication link CL can be obtained.

From the source communication unit 14, the sub-links are sent to means 21 for monitoring the bandwidth of each sub-link. average 21 sublink.

Said bandwidth indicator belonging to all monitors reads each It is preferred that sub-links must include a correct bandwidth indicator.

The various inputs 16 are connected to Data Information in a sublink SLk to the source communication unit 14. the means 21 are transmitted from the source communication unit 14 and then the packing means 23. The means 23 constitute means for packing the data of the sub-links in a continuous data stream. The means for monitoring 21 and the means for packing 24 are connected to and allocating are controlled by those means 22.

The packing agents Im4ltiplexar ~ the sub-links to one. data stream transmitted by the transmitting means 24 via the communication link CL to the second node 12.

The means for inserting the applicable bandwidth indicator BIk into the respective sublink SLk can be provided by a protocol converter 19, the means 21. connected to the monitoring protocol converter 19 has a memory unit 20, in which protocol data regarding the various inputs 16 is stored.

Protocol data indicates whether an input 16 nwttar a sublink carrying an indicator or a sublink lacking an indicator. The protocol converter 19 automatically introduces bandwidth indicator bits in a sublink that lacks an indicator, e.g. in the sublink's start label. If the bandwidth of a sublink changes, the value of the indicator is changed by the protocol converter 19.

The protocol converter 19 compares the saved indicator value of a sublink with the corresponding received indicator value. When the saved indicator value differs from the received value, the protocol converter will change the incorrect value to the saved value. The protocol converter 19 provides the system 10 with the ability to change the bandwidth indicator without changing the protocol. However, the protocol converter 19 and the associated memory 20 can be excluded if the appropriate bandwidth indicator is downlinked into the data stream already in the generators 15.

The bandwidth information is read by the allocating means 22 in the first node 11, which will use this information to control the means for packing each sublink into a serial (or parallel) data stream. The allocating means 22 are programmed to combine the received sublink in a data stream with the total bandwidth Bwt.

The second node 12 in the system 10 is considered a slave node and comprises a control unit 17, which can receive control data and control signals from the control unit 13 in the first node 11.

The second node 12 also comprises receiving means 25 for receiving the transmitted data stream from the first node 11, means 26 for reading data from the data stream, means 28 for dividing the data stream into different sub-links and means 27 for controlling the dividing means 28. Finally, the node 12 also comprises means for distributing the data information in each of the sub-links to the various outputs 30, respectively.

The communication link (HJ is connected to the receiving pins 25, which receive the data stream and forwards the data stream to the reading means 26. These reading means 26 are connected to both the dividing control means 27 and the dividing means 28. The digital information and path width indicators which are arranged in the sublink generator 15 or introduced by the protocol converter 19, sonx described above, now appears on the second node 12 as a data stream, preferably divided by the bandwidth indicators B1.

The bandwidth indicators BIk are detected in the serial data stream and read by the reading means 26 and this information is transmitted to the dividing control means 27. The dividing control means 27 send control signals to the dividing means 28, which, based on the read bandwidth indicators B1, divide the received data stream the connected reading means 26 in data information belonging to each of its sub-links according to the value. on the respective indicators and. distributes' denx via the subsequent distributing unit 29 to the correct outputs 30. Thus, for a certain bandwidth indicator BIk read by the reading means 26, an information signal is sent to the dividing control means 27, which give a control signal to the information indicating that dividing means 28, follows on the bandwidth indicator BIk the correct sublink SIk is transmitted. The dividing means 28 may be constituted by an ordinary switch, which may be controlled by the dividing means 27. The outputs 30 are connected to the destination units 31. Each and every one. one of units 31 comprises a sublink receiver (not shown), which reads the bandwidth indicator BIk belonging to the received information via sublink SLk. As mentioned above, this bandwidth is given by the inserted broadband indicator for the specific sublink about the necessary bandwidth for proper reception in the destination unit 31.

As an example, the system can use three sub-links SL1, SL2 and SL3 where each has a maximum bit rate of 64 kbit / s. To transmit this information at these bit rates, a transfer medium would require 3x64 = 192 kbit / s equal to the maximum If the sub-doctors bit rate for these three transmissions.

SL1-SL3 in the case of a special transfer would require only, eg bl = 32; b2 = 32 and b3 = 64 kbit / s, a 3x64 kbit / s transmission medium would still be used. In the present method, the bandwidth indicators would indicate that the transmission medium will only require 32 + 32 + 64 = 128 kbits / s.

Since it is rare that all sub-links use the available transmission medium to the maximum and at the same time and each with its maximum speed, it will be a waste if the communication link CL is dimensioned for this case.

The data stream is transmitted via the transmitting means 24 via the communication link CL to the receiving means 25 of the second node 25. The receivers constitute only an interface unit between the communication link CL and the function modules of the second node 12. The receiving means 25 sends the data stream to the reading means 26 which read the bandwidth indicators of the sublinks. This information is used by the dividing means 28, the various bandwidth indicators for the information to the dividing control means 27 which divide the data stream in those sub-links according to said reading indicators. was the following sublink and. its associated BIk can be found.

After the division. of the data stream ', the sub-links are forwarded to a distributing unit 29 with several outputs 30. Each. of the inputs are connected to the destination unit 31. The distributing unit 29 forms an interface between the outputs and the operating modules of the node 12. and one of and the other Var units 31 includes a sublink receiver 32 which detects the bandwidth indicator of the received sublink. The indicator is used as information to control and adjust the destination unit 31 to the correct sublink bandwidth.

Fig. 2 'shows a flow chart illustrating the steps in the case of the sublink generator. invented the method in the bandwidth indicator provided by the bandwidth indicator value BOB: determined on. basis of 'it. requested the bandwidth of a sublink SLk and is provided by a sublink generator 15 in Fig. 1 together with the data to be transmitted via that sublink. In a first step, step 40, the sublink link data is received predetermined path width indicator BIk from including it thus together with data and bandwidth indicators other sublinks in the system.

In the next step, step 41, packing of said sublink takes place next to one of the immediately preceding or subsequent ones to build up a continuous data stream within the total bandwidth Btot - The last step, in the first node, is to transmit step 42, the sublink via said data stream via said communication link CL to the second node. The first step in the second node, step 43, is to receive the data stream via a communication link, eg CL in Fig. 1. The next step, step 44, is to read each sublink indicator BIk when they arrives and passes these to the allocating means to control the next step, step 45, a division of the data stream into the original sub-links. The previous and final step 46 is to distribute each sublink to the correct sublink indicator.

In another case, the required bandwidth is monitored by checking a sublink in the first node, the value BI of the bandwidth indicator is determined in the first node (in the protocol converter 19), indicating the required bandwidth of that sublink.

Fig. 3 shows a frame structure for a transmission between nodes 11, 12 in the communication system according to Fig. 1. The frame structure comprises a number of fields F1, F2, now Fn, each of which contains control data and data information to be transmitted via the communication link CL for each sublink. . sublink SLk Thus, one exhibits its own frame structure depending on the required bandwidth indicated by bandwidth indicator BIk in accordance with the present invention. However, two (or more) sub-links may have the same frame structure if they have the same bandwidth requirements.

Field F1 usually has a frame label, which indicates the beginning of the frame (not shown). One this field can link. and BI2, unused space in used for the bandwidth indicator BI for resp. In Fig. 3, two bandwidth indicators B11 are each indicated, occupying two bits as shown. Indicator BI1 belongs to the data information transmitted via sublink SL1, while indicator BI2 belongs to data information transmitted at sublink SL2. In this example, the sublink SL1 requires greater bandwidth than the sublink SL2 and therefore BI1> BI2. 10 15 20 25 30 53 "! .'21 l (-; \\ 'Ill (_) \ 13 The second field F2 contains frame synchronization patterns (not shown) for synchronizing the receiver when the frame is to be received, for example in the destination unit 31.

The remaining fields F3, m., Fn are to be used and may contain the data information being transmitted, leftover bits and bits of protection. Since these parts of the frame structure have nothing to do with the inventive concept, they have not been discussed in detail here. the bandwidth indicator According to the invention, BIk for the sublink SLk is inserted in the unused space in the field F1, marked by the respective bandwidth indicators. in Fig. 3. Soul mentioned above, the bandwidth indicator value can be entered already in the transmitting sublink generators 15 on the first node 11 or added by the allocating means 22 on the transmitter side.

The SLk frames of the other sublinks have been organized in the same way, either. with the same. protocol or -med. a bandwidth indicator BIk. This can be done at the beginning of the frame shown in Fig. 3 or in the middle of the frame.

Fig. 4 shows three optional sublink frames FRX, Frx + 1, FRx + 2, which for each sublink SL1, SL2 and SL3 arrive at the packing means 23 to be multiplexed to form a serial bitstream which is transmitted via the medium CL. Each frame FRX, Frx + 1, FRx + 2 transmits data and bandwidth indicators BI1, SL1, SL2 and SL3.

BI2 and. BI3 for the three sub-links Each frame has a number of bits and all the bits in a frame form a block as previously shown in Fig. 3.

It is assumed that SL1 requires more bandwidth than the sublink SL2 and that the sublink SL3 needs more bandwidth. than each one! the other sublinks SL1, SL2. 10 15 E BJ 1 606 14 B2. The bandwidth indicator BI3 ooh the consecutive frames FRX and FRx + 1. FRx + 2 is displayed.

The sloping area of the remaining bandwidth up to the total available bandwidth Bwt for the communication link CL in Fig. 2 is intended to represent the bandwidth which would have been required without applying the method of the present invention.

The invention is not limited to the embodiments shown in Fig. 1 and Fig. 2. It can also be used for transmission from the node 12 to the node 11, i.e. in the opposite direction in the case that the destination units 31 may consist of sub-link generators and and the sub-length generators 15. Destination units thus constitute used for full duplex transmission.

Claims (10)

10 15 20 25 30 35 5231 686 15 Patent claims A method for bandwidth-adapted use of a bandwidth-limited communication link (CL) (l1, l2) in between a first and a second node a circuit-switched, frame-based communication system in which digital information from a number of generator units (15) communicating with the first the node (II) is transmitted via a number of sub-links to the respective destination terminals (31), which communicate with the second node (12) via a corresponding number of sub-links (SLk), said communication link (CL) having a determined total bandwidth (Bum), comprising the following steps: determining a bandwidth indicator (B1, B12, etc.) for at least one of said sub-links (SLk), the indicator indicating the minimum necessary bandwidth for transmitting said digital information via the respective sub-link; providing (40) said bandwidth indicators (15) (Blk) in a determined generator unit which communicates with the first node (II); combining (41) said sub-links (SLk) within the total bandwidth (Bum) into a data stream; transmitting (42) said data stream including the bandwidth indicator via the communication link (CL) to the second node. A method according to claim J. comprising the following further Steps: receiving (12): (43) the transmitted data stream in the second node reading (44) of the bandwidth indicator into a number of sub-links (SLk, SLk + 1, W) subdivision (45) ) of the sub-links in accordance with the read bandwidth indicators and distribution (46) of the sub-links thus read individually to their respective destination unit (31). 10 15 20 25 30 35 16 A method according to claim IL, wherein the bandwidth indicator (BIk) is transmitted in a determined fixed position in each sublink according to a special protocol associated with that transmission. 4. Method for bandwidth-adapted use of a bandwidth-limited communication link (CL) between a first and (l1, l2, a second node respectively) in a circuit-switched, frame-based communication system 'in transmitting and receiving digital sub-links said bandwidth information via a number (SLk ), the communication link (CL) having a determined total (Bum), comprising the steps of: monitoring (21) the required bandwidth for each sublink; bandwidth indicator (sLk), inserting (19) one (BI1, BI2, m.) into at least one of said sub-links, the indicator indicating the least necessary bandwidth for transmitting said digital information via the respective sub-link (SLk); allocating (22) and combining (23) said sub-links (SLk) within the total bandwidth (Bum) to a data stream; transmitting (24) said data stream comprising the bandwidth indicator at a certain fixed position in each sublink according to a certain protocol via the communication link (CL) to the other node. The method of claim 4, further comprising the steps of: receiving (25) the data stream at the second node; reading (26) each of the bandwidth indicators; and division (28) of the 'data stream' into the various sub-links. according to (BI1, (29) the indicators BI2, m.), and the distribution of the data information on each sublink to the respective destination unit (31). A circuit-switched, frame-based communication system which comprises means for bandwidth-adapted use of a bandwidth-limited communication link (CL) between a first node 10 15 20 25 30 5,921 Gí fl ëâ 17 A circuit-switched, frame-based communication system which includes means for bandwidth-adapted. use of a bandwidth limited communication link (CL) between a first node and a second node in the system and comprising a number of generator units (15) which communicate with the first node (ll) via a number of sub-links, where digital information is transmitted to the respective destination terminals which. communicates (12) (31) with. the second node via a corresponding number of sub-links (SLk), comprising: means for arranging bandwidth indicators (BIk) in a certain generator unit (15) belonging to the first node (II), the indicators having a value indicating the minimum bandwidth (Bk) which is needed for transmitting data associated with this generator to a destination unit (31) belonging to the second node (12) via a certain sublink (SLk), means (22,23) for allocating and combining sub-links within the total bandwidth Bwt to a data stream , means (24) for transmitting the data stream comprising sublink bandwidth indicator (SLk) (BIk) in a determined fixed position in each sublink via the communication link (CL) to the other node. Systenx according to claim 6, comprising the further means (25) for receiving the data stream in said second node (12), (25) sub-links (SLk, SLk + 1, ..), means for reading the bandwidth indicator in a number means (28) for dividing the sub-links in accordance with the read bandwidth indicators and means (29) for distributing the thus-read sub-links individually to the respective destination unit (31). Circuit-switched, frame-based communication system, comprising means for path-width-adapted use of a limited communication link between a first and a second node in E21. 6136 18 system and comprising an anal generator units (15) which communicate with the first node (II) via a number of sub-links, where digital information is transmitted to the respective destination terminals (31), which communicate with the second node (12) via a corresponding number of sub-links (SLk), a fixed sublink which requires a certain minimum bandwidth (Bk) comprising means (22,23) for allocating and combining sublinks within the total bandwidth Bu fl to a data stream, means (24) for transmitting the data stream comprising a bandwidth indicator (BIk ) in a certain position in each sublink via the communication link to the other node, means (25,26,28) at this node for reading the sublink bandwidth indicators and dividing the data stream into the different sublinks according to the indicators. A system according to claim 8 comprising further means (21) in the first node for monitoring the required bandwidth for each sublink (SLk) and means (19,20) belonging to the monitoring means (21) for inserting the bandwidth indicator (BIk) in respective sublink (SLk) corresponding to the requested bandwidth (Bk). The system of claim 8, wherein said means (19,20) for insertion is a protocol conversion means (19) and memory means (20). (20) (BIk). wherein the memory means stores a number of possible values on the bandwidth indicators