Title of Invention

ADAPTIVE PHYSICAL TRANSMISSION MODE SELECTION

Abstract

A data transmission network comprises two groups of nodes (1; 2, 3, 4), a radio interface associated to each group and connected to the nodes (1) of the group and a radio path (5) between the two radio interfaces (9), in which several groups (1412, 1413, 1414) of virtual paths (15) of warranted bandwidth are transmitted between one node (1) of the first group and one node (2, 3, 4) of the second group. The sum of the bandwidths warranted to the groups (1412, 1413, 1414) of virtual paths does not exceed the total bandwidth of the radio path (5) when operated in a transmission mode referred to as basic mode. The radio interfaces (9) support several physical transmission modes of different bandwidths and are adapted to detect the transmission quality of the radio path (5) and to operate, the transmission quality of the radio path (5) permitting, the radio path (5) in a transmission mode of higher bandwidth than that of the basic mode and to use the bandwidth difference between the used mode and the basic mode for bandwidth need of the groups of virtual paths in excess of the warranted bandwidth.

Full Text

FORM 2 THE PATENTS ACT, 1970 (39 of 1970) & The Patents Rules, 2003 COMPLETE SPECIFICATION (See section 10, rule 13) "ADAPTIVE PHYSICAL TRANSMISSION MODE SELECTION" MARCONI COMMUNICATIONS GMBH of Gerberstrasse 33, 71520 Backnang, Germany. The following specification particularly describes the invention and the manner in which it is to be performed. y^j^SK 7*/"" WO 2005/057836 2 PCT/EP2004/053359 ADAPTIVE PHYSICAL TRANSMISSIOW MODE SELECTION The present invention relates to a method for transmitting data in a network and a network in which such a method is applicable. Modern telecommunication networks must support a plurality of different services, which differ in their quality requirements, e. g. concerning their bandwidth needs, admissible signal transmission delays, variability of the data rate etc. New telecommunication standards such as ATM (Asynchronous Transfer Mode) take account of this need in that they allow so-called virtual paths to be defined, in a unitary transmission infrastructure, in which data from many individual communications between terminals connected to the network which have the same quality requirements may be transmitted between nodes of the network. Since the abolition of the telecommunication monopoly, a large number of private providers of telecommunications services have appeared on the market, which, at least in part, share an existing telecommunication infrastructure, e. g. by permanently hiring a certain portion of die bandwidth of an existing transmission line in order to provide it to their clients for their terminal-to-terminal communications. The degree of capacity utilisation that can be reached on such a transmission line is not improved by dividing it between different providers. As long as the transmission line is under the control of a single provider, he may allow additional terminal-to-terminal connections to be established via the transmission line, until its total capacity is no longer sufficient to accommodate therein a further connection. However, if the transmission line is hired to various providers, each one of them can only allow terminal-to-terminal connections WO 2005/057836 3 PCT/EP2004/053359 within the bandwidth hired by him; new connections that would cause the hired capacity to be exceeded cannot be allowed, even if a bandwidth portion hired by another provider is partially idle. In US 6,097,722 it is suggested to allow providers, which use several groups of virtual paths in an ATM transmission line, to temporarily exceed the bandwidth hired by them by “lending" them bandwidth, which belongs to another provider but is presently not used by him. It must be possible to return this lent bandwidth to its "proprietor" at any time, if he claims it, so that the lender must not use it for high-value services which require continuously available bandwidth or short signal transmission delays. The object of the present invention is to provide a method for data transmission in a network and a network appropriate for carrying out the method, where a transmission line is simultaneously used by several users, each of whom has been warranted part of the total bandwidth of the transmission fine for his exclusive use at any time. The method and network permit allocation to a user of bandwidth beyond the warranted extent with an increased availability and which will eventually enable use of this additionally provided bandwidth for high-value services. The invention is based on the use of a radio path as the transmission path and on the fact that the transmission quality on a radio path depends on conditions that vary with time, such as the climatic conditions reigning around it, interferences of several propagation paths or jammers at a same frequency. In order to ensure a required high availability of the radio path of 100%-e (i.e. the radio path must be available with a specified WO 2005/057836 4 PCT/EP2004/053359 bandwidth during a portion of 100%-e of the operating time of the network, e being much smaller than 1 %), a physical transmission mode, i.e. a combination of modulation and coding, must be used on the radio path which is operable even under very unfavourable climatic conditions. Only during a portion e of the operating time of the radio path, the climatic conditions may be so bad mat they cause a disturbance of the transmission on the radio path. The higher the availability requirements are, the more robust must the physical transmission mode be chosen, and the greater is the bandwidth difference between this transmission mode, referred to as basic mode, and a less robust but faster mode, which might be used under favourable climatic conditions. According to the invention, by monitoring the transmission quality of the radio path and, transmission quality of the radio path permitting operating it under a transmission mode having a higher bandwidth man the basic mode, at least temporarily additional bandwidth is obtained winch may be used for temporary bandwidth needs of a provider which exceed the portion of the total bandwidth of the radio path in basic mode which has been hired by him and warranted to him. The higher the required availability is, i.e. the smaller e is, the higher is the probability that at an arbitrarily chosen instant additional bandwidth may be generated by using a faster mode than the basic mode. According to a first simple embodiment of the method, the radio path is permanently operated under the physical transmission mode, which has the highest bandwidth among the transmission modes that are compatible with the detected transmission quality of the radio path. This method requires a continuous adaptation of the transmission mode to the climatic conditions, but if a provider needs bandwidth in excess of the portion hired WO 2005/057836 5 PCT/EP2004/053359 by him, the highest bandwidth achievable under die given conditions is available at all nines. According to an alternative second embodiment of the method, among the transmission modes compatible with a detected transmission quality of the radio path, the used one is the most robust one, the bandwidth of which satisfies the total bandwidth need, which is formed of the bandwidth hired by the individual providers and the bandwidth used by them in excess of the hired portion. Changes due to varying climatic conditions are less frequent here than in the first embodiment; here, the most frequent cause for changes of die transmission mode are fluctuations of die bandwidth need of die providers. An advantage of this method is mat me radio path may always be operated at the lowest possible transmission power, so mat jamming of other radio paths using a same frequency range is avoided. A possible compromise is mat if the total bandwidth need of the various providers is less than the bandwidth of die broadest one of die transmission modes compatible with die detected transmission quality of the radio path, me used transmission mode is the most robust one of die compatible transmission modes, die bandwidth of which covers die total bandwidth need plus a safety margin. The existence of the safety margin allows to satisfy from it bandwidth needs of the providers exceeding the hired portion for short times without before having to change die transmission mode. A particularly advantageous possibility for adapting to small changes of die bandwidth need without having to change die transmission mode is an adaptation of the WO 2005/057836 6 PCT/EP2004/053359 transmission power. In this way, if a switchover to a faster mode has been found to be necessary, as a preparation for this switchover the transmission power in the old mode may be increased for a short time in order to decrease the bit error rate and to decrease die number of cells which must be retransmitted due to a transmission error. If various services are transmitted on the radio path, not all of which have a constant bit rate, is difficult to estimate the total bandwidth need from the service qualities mat have been agreed for individual terminal-to-terminal connections. A simple possibility for estimating a discrepancy between the bandwidth of the presently used transmission mode and the total bandwidth need of the providers is the use of a buffer at the transmitter-side radio interlace of the radio path in which data to be transmitted is buffered, wherein it is found that the presently used transmission mode does not satisfy the total bandwidth need if the filling level of the buffer exceeds a predefined limit. Since die dwell nine of the buffered data in die buffer cannot be easily specified, buffered data should only be that which belongs to virtual path having an unspecified bit rate. An admission control (call admission control, CAC) in which it is decided whether a new terminal-to-terminal connection is to be admitted or not is carried out for each group of virtual channels independently from the other groups. Further features and embodiments of the invention become apparent from the subsequent description of embodiments referring to the appended drawings: WO 2005/057836 7 PCT/EP2004/053359 Fig. 1 is a schematic block diagram of a first embodiment of a network according the invention; and Fig. 2 is a block diagram of a second embodiment of a network. As a highly simplified example of a network according to the invention, in Fig. 1 a network is shown having four nodes 1,2, 3,4 which are daisy-chained to each other by radio paths 5,6,7, in winch data is transmitted packed into ATM cells. Each node 1 to 4 may be regarded as formed essentially of two components: a radio interface 9 and a terminal interface 10. The interfaces 9 and 10 are both bi-directional, but in the following, for the sake of simplicity, only one transmission direction is considered, i.e. the node 1 is described only in its function as a transmitter node, and me nodes 2 to 4 as receiver nodes. A symbolic enlarged detail illustrates the data traffic on radio path 5 from node 1 to node 4. The data traffic on this radio path 5 is formed of three groups 1412,1413, 1414 of virtual paths 15. The virtual paths 15 of each group extend between the same nodes 1,2 or 1, 3 or 1, 4 and differ from each other in the agreed service quality of the communications transmitted in them between terminals connected to the nodes. Since only one transmission direction is considered, the terminals connected to a transmitter node 1 will also be referred to as sources, and the terminals connected to the receiver nodes 2,3 or 4 as drains. WO 2005/057836 8 PCT/EP2004/053359 The part of the bandwidth of the radio path 5 which belongs to each individual group 14 is defined by agreement between an operator of the network and the telecommunication service provider who uses die concerned group 14, and the sum of these portions is not more man the total bandwidth of the radio path 5, when a combination of modulation and coding referred to as basic mode is used on the radio path 5. Each pair of nodes 1+2, 1+3 and 1+4, respectively, may use the portion of the bandwidth, of radio path 5 assigned to it freely and without coordination with the needs of the other node pairs. It must only be ensured before establishing a new communication between terminals of a pair of nodes mat the requirement of this communication concerning the transmission quality may still be satisfied within the portion of the bandwidth of radio path 5 winch is assigned to the concerned node pair. Methods to ensure this are known in the ATM field as Call Admission Control (CAC) and need not be explained hare in detail. In Fig. 1, a CAC processor 12 is shown in the terminal interface of node 1 for each group 14 of virtual paths to which die node 1 is connected, but it is understood mat these processors need not be present as multiple circuits but may be formed of a single circuit which carries out the CAC processing for the individual groups 14 in time multiplex. If the CAC processing indicates that a new communication between terminals of nodes 1 and 2 cannot be established, because in die portion of the bandwidth of the basic mode which belongs to die group 1412, there is no more capacity available, this communication is not rejected by the terminal interface 10 of the invention, but instead WO 2005/057836 9 PCT/EP2004/053359 the terminal interface 10 sends a request to a control unit 13 of the radio interface 9 of node 1 in order to find out if additional transmission capacity between nodes 1 and 2 can be provided. The radio interfaces of the nodes 1 to 4 support a plurality of physical transmission modes, i.e.. of combinations of modulation and coding, which vary in robustness and bandwidth, and are capable of establishing, besides the virtual paths 15 of the individual groups 1412, 1413, 1414, an additional virtual path 16 for traffic with variable or unspecified bit rate, which is not assigned to any other groups. Further, they comprise means for monitoring the transmission quality on the radio paths 5,6,7. According to a first embodiment, the control unit 13 of node 1 selects, according to the transmission quality detected e. g. by measuring the signal-noise-ratio, the one among the supported transmission modes which has me highest bandwidth compatible with the detected quality of radio path 5 and uses it on radio path 5. i.e.., although the bandwidth of the basic mode is only e. g. 15 Mb/s, at an instant when the control unit 13 receives the request of the terminal interface 10 for more transmission capacity for the group 1412, me transmission capacity of the radio path 5 may be e. g. 30 or 60 Mbit/s, because the transmission conditions are good and a less robust transmission mode with a high bandwidth is used. In this case, the control unit 13 responds positively to the request from the terminal interface 10. Since the virtual path 16 does not have the availability 100 %-e specified for the basic mode of the radio path 5, die required capacity cannot be permanently warranted to the WO 2005/057836 10 PCT/EP2004/053359 terminal interface 10. It cannot therefore use the capacity of the virtual path 16 for communications at constant bit rate (CBR), but for those of variable bit rate (VBR) or unspecified bit rate (UBR), so that the requested communication may eventually still be admitted. If the communication to be established is UBR or VBR traffic, it may be conveyed on the virtual path 16; if it is CBR traffic, the terminal interface increases die portion of die bandwidth of group 1412 belonging to the virtual CBR path at the expense of the UBR or VBR paths of this group, and thus displaced UBR or VBR traffic is conveyed on the virtual path 16. According to a second embodiment, the control unit 13 monitors the transmission quality so that it is able at any time able to decide which presently possible combination of modulation and code has the highest transmission capacity, but it always uses the most robust one among die presently possible combinations, which is still sufficient to cope with the present data traffic. In this way the transmission power may be kept low in average, and the jamming of adjacent transmitters is kept small. To this effect, it comprises a transmission buffer in which data of the virtual UBR paths of the groups 1412, 1413, 1414 may be buffered before being transmitted, and means for monitoring a filling level of the transmission buffer. This transmission buffer enables the radio interface 9 to satisfy immediately a request of a terminal interface for more transmission capacity, even if the bandwidth of the transmission mode presently in use would probably not be sufficient to cope with the additional communication, by buffering in the transmission buffer the increase in data traffic caused by establishing die communication until the switchover to a faster transmission mode has been carried out Herein, the filling level of me buffer is taken as a criterion for necessity of switching to WO 2005/057836 11 PCT/EP2004/053359 another transmission mode; if it rises above a first critical limit, it is necessary to switch to a faster transmission mode in order to avoid an overflow; if it drops below a second, lower critical limit, the presently used mode is faster man necessary, and a more robust mode at lower transmission power can be used in its place. According to an advanced embodiment, the control unit 13 also controls the transmission power on the radio path based on the bandwidth need. Short-term peaks of bandwidth need may be absorbed by increasing the transmission power above a set value, so as to decrease the bit error rate on the radio path 5 and to decrease the number of cells which must be retransmitted due to a transmission error. A criterion for this increase of transmission power is that, as described above, the filling level of the buffer exceeds a limit value. In order not to jam adjacent radio paths, me duration of the transmission power increase should be kept as small as possible. The control unit therefore switches to a foster transmission mode as soon as possible and reduces the transmission power to the set value again. If the control unit 13 receives a request for additional transmission capacity e. g. for the group 1412, and the conditions for radio transmission are bad, so that no capacity in excess of the 14 Mbit/s of the basic mode is available on the radio path 5, the request must not yet necessarily be refused. Instead, in such a case the control unit 13 obtains the load level of the other groups 1413,1414 of virtual paths from the CAC processors assigned to them in terminal interface 10, and if it is found that one of the other groups would still be capable of conveying the expected data rate of the additional communication, the control unit 13 permits the requesting terminal interface 10 to WO 2005/057836 12 PCT/EP2004/053359 exceed its assigned portion of the bandwidth of the radio path, so that it can grant the communication request Fig. 2 is a schematic block diagram of a portion of a second embodiment of a network according to the invention. Two physical nodes 20, 21 are shown, which communicate with each other by a radio path 5. The physical nodes 20, 21 are divided by software means into a plurality of virtual nodes 1a, 1b, 1c and 2a, 2b, 2c, respectively, which are used by different providers a, b and c, respectively. Each virtual node is connected to terminals of clients of the respective provider and/or to other real or virtual nodes, not shown, of this provider's network. In view of the data transmission on radio path 5, the virtual nodes 1a, 1b, 1c correspond to a transmitter node 1 of Fig. 1, and the virtual nodes 2a, 2b, 2c correspond to the receiver nodes 2,3,4. Radio interfaces 9 of nodes 20,21 are identical to those of Fig. 1, and also the division of the bandwidth of the radio path 5 into several groups 14a, 14b, 14c of virtual paths 15, of which each group corresponds to the data traffic between a virtual transmitter node 1a, 1b, 1c and the radio interface 9 of the physical node 20 and between the radio interface 9 of the physical node 21 and one of the virtual receiver nodes 2a, 2b, 2c, respectively, and path 16 not assigned to any group is the same as in case of Fig. 1. Virtual nodes such as 1a, 2a of provider a communicate by an associated group 14a of virtual paths. WO 2005/057836 13 PCT/EP2004/053359 If a pair of virtual nodes such as 1a, 2a requires more transmission bandwidth man what corresponds to its associated group 14a of virtual paths, the handling is exactly the same as in case of the network described referring to Fig. 1. WO 2005/057836 14 PCT/EP2004/053359 CLAIMS 1. A method for data transmission on a radio path (5) between two radio interfaces (9), which support a plurality of physical transmission modes at different bandwidths, comprising the steps of: a) establishing a plurality of groups (1412,1413,1414; 14a, 14b, 14c) of virtual paths (15) on the radio path (5), each having a warranted bandwidth, so that the sum of the bandwidth warranted to the groups does not exceed the total bandwidth of the radio path operating in a transmission mode referred to as basic mode, b) detecting the transmission quality of the radio path (5), and, the transmission quality of the radio path permitting, c) operating the radio para (5) in a transmission mode of higher bandwidth than mat of the basic mode and using the bandwidth difference between me used mode and the basic mode for bandwidth need of the groups (1412,1413, 1414; 14a, 14b, 14c) of virtual paths (15) in excess of the warranted bandwidth. 2. The method in claim 1, characterised in that the radio path (5) is operated in the transmission mode having the highest bandwidth compatible with the detected transmission quality of the radio path (5). 3. The method of claim 1, characterised in that if the total bandwidth need of the groups (1412,1413, 1414; 14a, 14b, 14c) of virtual paths (15) is less than the bandwidth of the broadest one of the transmission modes compatible with the detected transmission WO 2005/057836 15 PCT/EP2004/053359 quality of the radio path (5), the most robust one of these compatible transmission modes is used, the bandwidth of which satisfies the total bandwidth need. 4. The method of claim 3, characterised in that small changes of the bandwidth need are satisfied by adapting the transmission power of the radio path (5). 5. The method of claim 3 or 4, characterised in that at least part of the data to be transmitted in a group (1412,1413, 1414; 14a, 14b, 14c) of virtual paths is buffered at the transmitter-side radio interface (9), and mat the presently used transmission mode is found not to satisfy the total bandwidth need if die filling level of the buffer exceeds a limit value. 6. The method of claim 5,characterised in that the buffered data of at least one virtual path of unspecified bit rate. 7. The method according to any one of the preceding claims, characterised in that in each virtual group, the admission of a new communication is decided by a CAC method. 8. A data transmission network comprising a first group of nodes (1; 1a, 1b, 1c), a first radio interface (9) connected to the nodes (1; 1a, 1b, 1c) of the first group, a second group of nodes (2,3,4; 2a, 2b, 2c), a second radio interface (9) connected to the nodes of the second group, and a radio path (5) between the two radio interfaces (9), in which several groups (1412,1413,1414 14a, 14b, 14c) of virtual paths (15) of warranted WO 2005/057836 16 PCT/EP2004/053359 bandwidth are transmitted between one node (1; 1a, 1b, 1c) of the first group and one node (2,3,4; 2a, 2b, 2c) of the second group, wherein the sum of die bandwidth warranted to die groups (1412,1413, 1414; 14a, 14b, 14c) of virtual paths does not exceed die total bandwidth of die radio path (5) when operated in a transmission mode referred to as basic mode, characterised in that the radio interfaces (9) support several physical transmission modes of different bandwidth and are adapted to detect me transmission quality of the radio path (5) and, die transmission quality of die radio path (5) permitting, to operate die radio path (5) in a transmission mode having a higher bandwidth than that of the basic mode, and to use die bandwidth difference between die used mode and the basic mode for bandwidth need of die groups of virtual paths in excess of the warranted bandwidth. 9. A method for data transmission on a radio path (5) between two radio interfaces (9) substantially as herein described with reference to the accompanying drawing. 10. A data transmission network substantially as herein described with reference to die accompanying drawing. Dated this 25th day of May, 2006. OMANA RAMAKRISHNAN OF K & S PARTNERS AGENT FOR THE APPLICANTS 17 ABSTRACT ADAPTIVE PHYSICAL TRANSMISSION MODE SELECTION A data transmission network comprises two groups of nodes (1; 2, 3, 4), a radio interface associated to each group and connected to the nodes (1) of the group and a radio path (5) between the two radio interfaces (9), in which several groups (1412, 1413, 1414) of virtual paths (15) of warranted bandwidth are transmitted between one node (1) of the first group and one node (2, 3, 4) of the second group. The sum of the bandwidths warranted to the groups (1412, 1413, 1414) of virtual paths does not exceed the total bandwidth of the radio path (5) when operated in a transmission mode referred to as basic mode. The radio interfaces (9) support several physical transmission modes of different bandwidths and are adapted to detect the transmission quality of the radio path (5) and to operate, the transmission quality of the radio path (5) permitting, the radio path (5) in a transmission mode of higher bandwidth than that of the basic mode and to use the bandwidth difference between the used mode and the basic mode for bandwidth need of the groups of virtual paths in excess of the warranted bandwidth.

Documents:

621-MUMNP-2006-ABSTRACT(11-1-2012).pdf

621-mumnp-2006-abstract.doc

621-mumnp-2006-abstract.pdf

621-mumnp-2006-assignment(27-3-2007).pdf

621-MUMNP-2006-CHINA DOCUMENT(11-1-2012).pdf

621-MUMNP-2006-CLAIMS(AMENDED)-(11-1-2012).pdf

621-MUMNP-2006-CLAIMS(MARKED COPY)-(11-1-2012).pdf

621-mumnp-2006-claims.doc

621-mumnp-2006-claims.pdf

621-mumnp-2006-correspondance-received.pdf

621-MUMNP-2006-CORRESPONDENCE(22-3-2012).pdf

621-mumnp-2006-correspondence(5-12-2007).pdf

621-mumnp-2006-description (complete).pdf

621-MUMNP-2006-DRAWING(11-1-2012).pdf

621-MUMNP-2006-EP DOCUMENT(11-1-2012).pdf

621-MUMNP-2006-FORM 1(11-1-2012).pdf

621-mumnp-2006-form 1(21-7-2006).pdf

621-mumnp-2006-form 1(27-3-2007).pdf

621-mumnp-2006-form 18(3-12-2007).pdf

621-MUMNP-2006-FORM 2(TITLE PAGE)-(11-1-2012).pdf

621-mumnp-2006-form 2(title page)-(29-5-2006).pdf

621-MUMNP-2006-FORM 26(21-6-2012).pdf

621-mumnp-2006-form 26(27-3-2007).pdf

621-MUMNP-2006-FORM 3(11-1-2012).pdf

621-mumnp-2006-form 3(29-5-2006).pdf

621-mumnp-2006-form 6(27-3-2007).pdf

621-mumnp-2006-form-1.pdf

621-mumnp-2006-form-2.doc

621-mumnp-2006-form-2.pdf

621-mumnp-2006-form-5.pdf

621-mumnp-2006-general power of attorney(21-7-2006).pdf

621-MUMNP-2006-JAPANESE DOCUMENT(11-1-2012).pdf

621-MUMNP-2006-PETITION UNDER RULE 137(11-1-2012).pdf

621-MUMNP-2006-REPLY TO EXAMINATION REPORT(11-1-2012).pdf

621-MUMNP-2006-REPLY TO HEARING(21-6-2012).pdf

621-mumnp-2006-specification(amended)-(27-3-2007).pdf

621-MUMNP-2006-US DOCUMENT(11-1-2012).pdf

621-mumnp-2006-wo international publication report(29-5-2006).pdf

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