Multiple access communications over diverse access technologies

Multiple access communications on various access technologies

TECHNICAL FIELD OF THE INVENTION

The present invention relates to communications. More especially, it refers to multiple access communications 5 on various access technologies. Particularly it refers to technologies of multiple radio accesses and heterogeneous networks.

BACKGROUND AND DESCRIPTION OF RELATED TECHNIQUE

For communications there are a variety of access technologies and more access technologies are being developed to meet the growing demand for capacity and requirements for maximum response times,

10 time fluctuation, etc. In particular, different radio technologies are known for radio communications such as GPRS (General Package Radio Services), UMTS (Universal Telecommunications Systems) and WLAN (Wireless Local Area Network) to transmit data packets over one of a plurality of networks available.

A network that operates according to only one access technology will be called a homogeneous network. A network that includes different access technologies will be called a heterogeneous network.

fifteen XG Wang, J. Mellor and K. Al-Begain, 'Towards the Provision of QoS for Integrated Cellular Networks and WLAN', Postgraduate Network Conference (PGNet2003), Liverpool, United Kingdom, June 2003, describes the interconnection of a WLAN radio access network with a 3G 6 2G cellular network as an efficient way to improve the service of the network operator. The publication describes two different methods for mixing or combining WLAN and cellular networks, with loose coupling

or wide and narrow coupling. There are two access networks for broadband and cellular networks WLAN

twenty separated, with main networks connected. For tight coupling they suggest that WLAN be used as a new radio access technology within the cellular system. Regardless of the access technology, for tight coupling there would be only one common cellular main network. According to the QoS model structure of the prior art, a CAC (Connection Admission Control) module supports the number of flows that can be served and allocates a bandwidth to the flows through the signaling of all nodes network along the

25 traffic path You also need to maintain the QoS requirements of existing connections. CAC uses some reservation protocols, for example, RSVP, to register the actual resource for user flow. The publication suggests a transfer triggered or triggered by the user when roaming from cellular networks to the WLAN and a normal transfer when roaming from WLAN to cellular networks.

XG Wang, G. Ming, J. Mellor, K. Al-Begain, L. Guan, 'An adaptable QoS management scheme to work between

30 cellular networks and WLAN ', 7th Conference of the Simulation Society of the United Kingdom (UKSim2004), Oxford, United Kingdom, March 29-31, 2004, pags. 145-150, studies different challenges generated by designing an integrated WLAN and 3G network and presents simulation experiments and results related to the use of resources, probability of blocking calls and probability of eliminating the transfer.

Ken Murray, Dirk Pesch: 'State of the Art: Admission Control and Mobility Management in Wireless Networks

35 Heterogeneas', TSSG, Waterford Institute of Technology Cork Rd, Waterford, Ireland, May 2003, describes roaming between seamless systems through heterogeneous networks. The motivation for heterogeneous networks is raised by the fact that no technology or service can provide continuous ubiquitous coverage and levels of QoS (Quality of Service) across multiple spaces. It will therefore be necessary for a mobile terminal to use different junction points to maintain connectivity to a corresponding node at any time. Both the services of

40 Switched circuit packets can be mixed freely, with variable bandwidth and delivered simultaneously to the same user with specific quality level. Satellite networks promise global coverage and total ubiquitous calculation but with lower QoS restrictions than their cellular opponents, while WLAN provides high-speed data service (up to 11 Mb / s with 802.11b and 54 Mb / s with 802.11a / g) over a geographically small area. The technologies differ in bandwidth, latency, energy consumption and cost. The control strategies of

Four. Five admission and mobility management facilitate load balancing between access networks. Users can be forced to transfer to another network to give way to users with more bandwidth demand requirements and users can thus be prioritized. It may be possible to use an admission control algorithm to admit a user to multiple networks simultaneously and use multiple connections to deliver services to the user and thus achieve a QoS greater than that offered from a single network. If there are multiple networks available to a user at any time, choose then

fifty The most optimal network for a particular service delivery and choosing the right time to execute a vertical transfer to improve QoS for all users are important factors. The publication describes concepts of confusing logic for transfer initiation, network selection and transfer execution. The document concludes that admission control schemes through heterogeneous networks based on radio channel characteristics, resource availability, QoS restrictions and user policies remain an open question.

CA Mantilla, JL March, 'A QoS Framework for Wireless Heterogeneous Networks using a Multiple Agents System', European Wireless 2004, Fifth European Wireless Conference on Mobile and Wireless Systems beyond 3G, February, 2004, describes QoS on the network Wireless heterogeneous, multiple agent systems and a QoS Framework in wireless heterogeneous networks that use a multiple agent system. The document proposes a system of multiple agents, where each access point in each technology or network has a group of agents with different missions, cooperating or competing. The global functions of the MAS (Multiple Agents System) include call admission control to accept or reject an incoming flame, call log with security policies, QoS parameters for assigning resources that correspond to a new network and transfer execution. A radio resource management agent is responsible for the state of the access point, the resources available and the execution of the horizontal transfer, or transfer within a technology, and the vertical transfer, or transfer between access technologies.

E. Mohyeldin, M. Dilinger, E. Schulz and J. Luo, 'Connection admission control and planning algorithm in tightly coupled heterogeneous networks', 6th WWRF meeting in London, England, June 2002, presents Admission Control two stages and Resource Programming for strongly coupled subnets (UMTS and WLAN). A radio network controller, RNC, owns and controls the radio resources of all subnets in its domain, where inter-subnet internal work primarily goes through the RNC. The incoming traffic within the systems is divided into different types of traffic after a first stage of Connection Session Admission Control, JOSAC. A second stage of Session Admission Control, SAC, selects the mode of physical transmission of support service or abandons the application in case the network cannot provide the requested service. Based on the static service chosen and the network profile in the first stage, the first stage of the admission control assigns a certain range for the weights defined for the types of service based on the network, terminal and user profiles, which are offered to the second stage. The traffic stream strongly coupled on two RATs (Radio Access Technologies) is programmed by JOSCH (Programming of Radio Connection Resources), working between the first and second stage. The traffic division after JOSCH is sent to individual SACs in each defined RAT subnet with delay limits. The SAC matches the divided traffic, with control information offered from JOSCH, with the type of conventional traffic with a specific priority weight. The QoS class dimension of the programming allocates resources for different QoS classes. The connection admission control assigns a radio resource to the corresponding amount of traffic in each subnet according to the subnet load, the expected traffic model and the possibility of dividing the traffic.

J. Luo, E. Mohyeldin, N. Motte, M. Dilinger, 'ARMH Performance Research in a Reconfigurable Environment', SCOUT Workshop, September, 2003, describes the ARMH (Adaptive Multihome Radio) concept for radio access technologies strongly coupled, RAT, and investigates simultaneous connections in individual radio networks with the support of multiple radio addresses belonging to terminals. For connection admission control, traffic cannot be divided; the session / messages cannot be divided over different networks, but they can be admitted alternately to a different one for packet switched communications. JOSAC can only give a profit due to the routing of traffic, or alternatively, the diversion of traffic to a different system. JOSCH offers the detailed traffic division.

In the event that a mobile terminal has simultaneous connections supported by reconfigurable terminals, data flows and control orders can be routed through different air interfaces, which has different delay characteristics in terms of medium delay and delay variance (variation fast). The traffic division is motivated by a reduced load on individual networks, thereby providing higher link gain as seen by the management of radio resources, RRM, and QoS better as seen by a user if the traffic division It is designed according to the profile and user requests, and the network architecture.

The document mentions an example, a terminal that requests a scalable video service from a remote server through tightly coupled subnets (UMTS and WLAN). Both networks are assumed to be controlled by a common RNC. In order to establish simultaneous subcurrents belonging to the same video context, the RNC first receives an application or a request from a mobile terminal with multiple radio accesses / addresses. The RNC applies or urges a remote server to divide the traffic, indicating the average rate in each sublink. The traffic is divided and sent to the RNC, which receives the divided traffic and makes it correspond to the strongly coupled subnets. The divided traffic comprises packages labeled (for each subnet) and indexed in time. A synchronization mechanism in RNC remedies the delays generated by radio subnets.

International Patent Application WO03088686 discloses a method of multi-service assignment in multiple access systems. Users of a given service in a wireless communication system that includes a plurality of multiple service subsystems are assigned to one of the subsystems according to a combined capacity region of the wireless communication system. The combined capacity region is determined based on the capacity regions of each of the plurality of multiple service subsystems, whose capacity regions are determined using a relative decrease in users of a first service as a function of an increase in users of a second service.

None of the documents cited above describe the admission control for access to multiple technologies, the admission control serving one or more sessions, each received by a multiple technology access system in a data stream, over more than one technology access at the same time by dividing a session on available access technologies, the division being made within the access system, or dividing individual data streams over more than one access technology. In addition, none of the documents cited reveals the data flow selection of access technology based on data security, or user or terminal preferences.

SUMMARY OF THE INVENTION

Control of admission of access to multiple technologies is an important part, as demonstrated in the prior art. The main purpose of the control of admission of access to multiple technologies is to protect QoS agreements already established with the access system of multiple technologies. The invention proposes a method and control system for admission of access to multiple technologies that satisfies this purpose while simultaneously improving the capacity of the system and the spectral efficiency of the complete system of access to multiple technologies.

A general problem of multiple technology access systems is to satisfy different session requirements with respect to, for example, QoS, security or specific terminal requirements when data is transferred. Another problem is how to incorporate such requirements when the traffic is assigned to the different technologies of a heterogeneous system.

The state of the art of MTA technologies increases the increased requirements on service providers or increases the risk of rejecting sessions and unnecessarily requiring high margins for reasonable abandonment rates of admitted sessions. In addition, user requirements or terminal requirements for example on security are not guaranteed.

Accordingly, there is a need to provide access control division sessions of access to multiple technologies in a plurality of data streams that do not impose increased requirements on different data service providers and that guarantee different specifications by not reserving more than minimum resources for resource margins, while providing sufficiently low dropout rates for supported sessions.

It is therefore an object of the present invention to achieve access admission control to multiple technologies that can provide the division of one or more communication sessions into a plurality of data streams for distribution over different access technologies.

Another object is to obtain an admission control of attempts that incorporates all the admitted data streams of the respective access technologies when a communication session is admitted.

It is also an object to achieve a method and system that provides selection of access technology and admission control of multiple access technology that incorporates security requirements or preferences of a user, terminal or service that initiates a particular session.

Another object is to provide multi-technology access admission control that includes predicting service efficiency or resource needs for different session split data flows.

Finally, it is an object to increase the reliability of the session in terms of probability of dropping out of admitted sessions or, equivalently, by reducing the required resource margins of one or more of the different access technologies, or their admission control, involved in the distribution distribution.

These objects are satisfied by a method and control system for admission of access to multiple tentative technologies.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 illustrates the admission control of MTA according to the invention.

Fig. 2 schematically illustrates the preferred MTA admission control that performs three identified tasks, in accordance with the invention.

Fig. 3 illustrates a simplified flow chart for selection of access technology for a communication session division according to the invention.

Fig. 4 illustrates how resources requested for a communication session requesting the amount of D resources are rejected for admission control in accordance with the prior art.

Fig. 5 mainly illustrates a tentative MTA admission control in accordance with the invention by admitting a communication session requesting the amount of resources of D.

DESCRIPTION OF PREFERRED EMBODIMENTS

In the access of multiple technologies, MTA, admission control is an important part, as demonstrated in the prior art. The main purpose of the MTA admission control, MTAC, is to protect the QoS agreements already established with the MTA system. The invention proposes a MTAC method and system that satisfies this purpose while simultaneously improving the system capacity and spectral efficiency of the total MTA system.

Fig. 1 illustrates the admission control of MTA according to the invention. The MTA system «MTA sys» coordinates several heterogeneous access technologies, ATs «ATA», «ATB», «ATC». The MTA system can route traffic over more than one "ATA", "ATB", "ATC" access technology for individual "session" communication sessions, either by assigning data streams from different "session" sessions to different "ATA" ATs »,« ATB »,« ATC »or by dividing individual data streams over more than one access technology« ATA »,« ATB »,« ATC ».

The individual access technologies "ATA", "ATB", "ATC" may be aware that the MTA system "MTA sys" as indicated in fig. 1 by a dotted line that encloses the admission control MTA «MTAC» and the integrated access technology «ATA», or not being aware that the MTA system «MTA sys» as for two exemplary access technologies «ATB», « ATC »indicated in the figure by the dotted line that does not contain the two exemplary access technologies not integrated« ATB »,« ATC ». The integrated access technology «ATA» is, for example, an access technology designed to take advantage of all the capabilities of the MTA system «MTA sys», while the non-integrated access technologies «ATB», «ATC» are, for example, legacy access technologies, originally designed to operate on their own.

Exemplary non-integrated access technologies, "ATB", "ATC" each comprise a homogeneous network admission control "ATB AC", "ATC AC" in accordance with the prior art. Also, the integrated exemplary access technology may comprise "ATA AC" homogeneous admission control in accordance with the prior art. Preferably, however, the respective admission control "ATA AC" of integrated access technologies is integrated with the admission control of MTA "MTAC".

The MTA admission control "MTAC" determines whether a communication session should be admitted to the MTA system "MTA sys" or not. The admission control entity of "MTAC" preferably requests information about the capabilities of the individual access technologies "ATA", "ATB", "ATC", or as a less preferred alternative, the key of the respective access technologies interrupts and pushes the information to the MTA admission control entity "MTAC" of the MTAsys MTA system.

The preferred MTA admission control performs three identified tasks, described in relation to fig. 2 as three operations or stages «T1», «T2», «T3». The first task «T1» is forming a set of attempts at access technology. This is done in two sub-operations.

<dl><dt>-</dt><dd>Form a preliminary set τ including access technologies that </dd></dl>

<dl><dt>• </dt><dd>are available and provide the required quality, and </dd></dl>

<dl><dt>• </dt><dd>they meet the minimum, non-divisible requirements for the communication session; </dd></dl>

and

<dl><dt>-</dt><dd>Verify that the preliminary set τ * can achieve the minimum divisible requirements for the communication session. </dd></dl>

An example of a minimum non-divisible requirement is a delay session requirement. Another example of a non-divisible minimum requirement is the need for secured / encrypted communication. A minimum non-divisible requirement is characterized in that it needs to be satisfied by at least one access technology involved when an inconvenience of an access technology cannot be compensated by a superiority of another access technology, so that the combined contributions satisfy the requirement. Consequently, non-divisible requirements cannot be satisfied by the additional division of data flows over more access technologies.

An example of a minimum divisible requirement is a minimum transmission rate requirement. The minimum exemplary requirement would be satisfied if the sum of the transmission rate capabilities of the access technologies in the preliminary set τ * is greater than or equal to the minimum transmission rate requirement. Another example of a minimum divisible requirement is reliability when different data flows can be combined with diversity.

If the preliminary set τ * in the first sub-operation is empty or if the minimum divisible requirement of the second sub-operation is not verified, the tentative set is empty, the MTAC entity rejects the communication session and the admission process of the session stops. The tentative set T is set identical to the preliminary set τ *, when verified.

The second task «T2» is to evaluate the allocation alternatives of a tentative set T not empty since the first operation «T1». The purpose of the second operation "T2" in the admission control of MTA, MTAC, is to first generate a prioritized list of allocation alternatives from the tentative set and evaluate the possibility of admission and the potential impact on resources, for example channel resources, of access technologies for the different alternatives. The cardinality of the set τ is indicated 1τ1.

If 1τ1 = 1, there is only one allocation alternative.

If 1τ1 = 2, there are at least three different alternatives, where three is the number of alternatives to select at least one in two.

For the general case, if 1τ1 = C, where C is an integer greater than zero, the number of allocation alternatives is equal to or greater than the number of alternatives to select at least one of C.

In practice, the number of access technologies considered is limited and consequently, the maximum cardinality Cmax is also limited.

There may be different objectives and aspects, possibly conflicting to consider when forming the prioritized list of allocation alternatives among the set of possible alternatives. An important aspect is that QoS agreements already established for existing users in the MTA system should be protected. This means that it is necessary to estimate the allocation of current resources and the increase in allocation for the different allocation alternatives.

Another aspect considered is that certain assignments may be less advantageous to provide some services than others. The fact that some services are only supported by some access technologies is already captured by the first task «T1», where inappropriate technologies are not included in τ. The evaluation of allocation alternatives preferably prioritizes the different allocation alternatives. Preferably also the entry from the congestion control and the use of resources of the different access technologies is considered in the prioritization process.

Allocation alternatives that minimize the consumption of channel resources in a communications system that comprises the MTA system, or that minimize the energy consumption for a wireless terminal, typically a portable terminal, or (virtually equivalently) minimize the number of access technologies involved for an admitted communication session are included in the prioritization process according to a mode of the invention.

In another mode of the invention, sub-requirements are defined for (sub-) respective flows of a communication session, where (sub-) flows would be assigned on the access technologies selected from the tentative set. In some exemplary assignments this results in another division of data flows from a subflow communication session.

When all allocation alternatives for consideration have been evaluated, an orderly prioritized list of allocation alternatives is available. For admission, alternatives are considered from higher to lower priorities, and the process is then stopped preferably at the first admissible allocation alternative identified.

Table 1 below illustrates an example of a prioritized sorted list, the alternatives being numbered from the highest priority to the lowest.

<dl><dt>Priority </dt><dd>Session Flow Tie ATB ATC </dd></dl>

<dl><dt>1 </dt><dd>Flow 1 100% 0% 0% </dd></dl>

<dl><dt>Flow 2 </dt><dd> 0% 100% 0% </dd></dl>

<dl><dt>2 </dt><dd>Flow 1 0% 0% 100% </dd></dl>

<dl><dt>Flow 2 </dt><dd> 0% 0% 100% </dd></dl>

<dl><dt>3 </dt><dd>Flow 1 fifty% fifty% 0% </dd></dl>

<dl><dt>Flow 2 </dt><dd> 0% 0% 100% </dd></dl>

Table 1

If the prioritized sorted list is empty, the communication session is not supported and the assignment process stops.

The third task "T3" is to select the allocation alternative from the prioritized sorted list. Since the session flows can be divided into sub-flows so that the sub-flows meet the divisible requirements so that the sub-flows can be assigned to different access technologies, the selection of alternative allocation is preferably attempt on all assignments under the MTAC. The selection process in the selection operation "T3" is illustrated in fig. 3.

The assignment is started by initializing "A1" a counter i to count the prioritized alternatives that preferably start with the highest priority alternative. Also initialized "A1" is an integer j representing the number of alternatives " alt. »In the prioritized ordered list. The resources for each flow according to the alternative considered "i" are reserved for each data flow or sub-flow, tentatively for each access technology "A2" sending requests to each admission control of individual access technology "ATAAC" , "ATBAC", "ATC AC" (see fig. 1) considered for assignment according to the prioritized alternative.

If the resources can be reserved for all flows, "A3" is reserved accordingly and the session "A4" is admitted. The selection operation «T3» of fig. 2 is therefore completed.

If the resources cannot be reserved for all flows of the instant alternative of the ordered list, the following alternative "A5" of the prioritized ordered list is investigated as described above, unless the instant alternative was the last in the Priority sorted list, in which case the sessions are rejected «A6». When the session is either "A4" or rejected "A6", the selection operation "T3" of fig. 2 is completed.

Figs. 4 and 5 illustrate how a session can be allowed according to the invention. In fig. 4 resources are requested for a "session" communication session that requires the amount of resources of D. For the non-tentative MTA admission control of fig. 4, the "session" communication session cannot be divided into multiple data streams but requires that the requested resource, D, completely from an "ATA", "ATB" access technology be admitted. The respective admission control of the access technologies "ATA AC", "ATB AC" investigates whether the requested resource "D" can be allowed by comparing the request with unoccupied resources "RA", "RB". Each access technology has a total amount of communication resources, for example channel bandwidth, equal to OA RA and OB RB, respectively, where OA and OB are busy resources, and RA and RB are unoccupied resources for access technologies A «ATA» and B «ATB» respectively. However, not all unoccupied resources can be allocated, but there is a minimum required margin of resources required MA, MB of access technologies "ATA", "ATB". The resource margin "MA", "MB" is a margin to allow sessions already admitted to increase your resource requirement. By introducing a “MA”, “MB” margin that is shared between users, access technology can support more users, because different users do not increase or statistically decrease their resource requirements simultaneously. The higher the number of users, the smaller the resource margin may be relatively in relation to the total unoccupied resources, for a specified probability that the full resource margin will be required. As the system of fig. 4 cannot split the session into separate flows that are to be distributed by the different access technologies "ATA", "ATB" the complete resource request "D" is compared with the respective resources available for assignment to new RA -MA sessions and RB -MB. Consequently, a requirement to admit the session to the multiple non-tentative access system of fig. 4 is that at least one of the inequalities

DRA -MA, and

D RB -MB

be satisfied The respective admission control "ATA AC", "ATB AC" of the access technologies "ATA", "ATB" investigates at least this requirement. For the example illustrated in fig. 4 the full session is rejected, since none of the “ATA”, “ATB” access technologies have, in their possession, resources available greater than the resource request.

Fig. 5 illustrates an admission control of tentative MTA "tentative MTAC" according to the invention. Similarly to fig. 4, there is a request for resources of quantity D for a session of communication "session". In contrast to fig. 4, the MTA admission control "tentative MTAC" can divide the communication session into two separate data streams "session flow 1", "session flow 2", which can be distributed over the different "ATA access technologies" »,« ATB ». In the illustrated example, the occupied resources "OA", "OB" and the unoccupied resources "RA", "RB" are identical to those in fig. 4. To simplify the presentation and focus on one problem at a time, it is initially assumed that the resource margins «MA», «MB» are identical to those in fig. 4. The admission control of MTA "Tentative MTAC" investigates whether the respective flows require fewer resources than are available. In the illustrated example, the communication session is divided into two data streams "session flow 1", "session flow 2" that require the same amount of communication resources, 0.5D. The invention, however, is not restricted to symmetric divisions of sessions. The admission control "ATA AC", "ATB AC" of the access technologies "ATA", "ATB" compare the resource requirement with the available resources and as both

0.5D RA -MA, and

0.5D RB -MB

turn out to be satisfied by the exemplary situation, both data streams "session flow 1", "session flow 2" can be admitted and, like all session requirements described in relation to figs. 2 and 3 turn out to be satisfied, the

Full session with resource requirement D is admitted by the admission control of MTA "Tentative MTAC" according to the invention.

As regards resource margins, it was initially assumed, for reasons of simplicity, that the "MA", "MB" margins were established identical for the non-tentative and tentative MTA admission controls in Figs. 4 and 5, respectively. However, due to the fact that the traffic of more users can be distributed on each access technology "ATA", "ATB" of fig. 5 that of fig. 4, the resource margins "MA", "MB" may be set lower with a tentative MTA admission control "tentative MTAC" according to the invention and schematically illustrated in fig. 5, without increasing the probability that the total resource margins «MA», «MB» will be required for the communication sessions and the allowed data flows. This is the case for both integrated and non-integrated access technologies.

Particular difficulties and the scarce nature of an exemplary wireless medium highlight the importance of not requiring greater margins of resources than necessary.

A preferred feature of the tentative MTA admission control in fig. 5, is the "tentative MTAC" admission control that does not support resource allocation if there are not enough resources available for all session flows. For the exemplary streams "session flow 1", "session flow 2", preferably none of the data streams "session flow 1", "session flow 2" is admitted if the other flow rates cannot also be admitted data "session flow 1", "session flow 2".

Another preferred feature of the invention is the access technology selected for each flow that is based not only on the general loading conditions of each of the access technologies considered but also on a prediction of service efficiency or resources necessary for the flow of specific data in the immediate future. This is achieved at a statistical level by determining a total service efficiency for each access technology or making measurements for one or more terminals considered, without excluding a combination thereof.

The invention is not restricted to pure QoS requirements, such as data rate, average delay and delay variance (rapid variation). Another feature of the invention is that sessions, in whole or in part, can be controlled for distribution over one or more access technologies, which provide the level of security required. As an example, the above WLANs may not provide the required level of security, while both UMTS and GSM GPRS may provide the required level of security. The admission control of MTA, MTAC, according to the invention then divides the session as needed and distributes one or more security sensitive session flows over UMTS or GSM GPRS, while less sensitive information can be distributed over the WLAN implementation less secure. The security requirement is preferably included as a divisible or non-divisible requirement, mutatis mutandis, as described in relation to fig. two.

The preferred embodiment of the invention consequently assigns the most efficient access technology in resources also considering the particular requirements / parameters such as user / terminal preferences, QoS parameters or security level, supported by some perone by all access technologies.

The invention applies to both wired and wireless access technologies, where traffic can be divided over a plurality of access technologies. Of particular interest, however, is access to multiple technologies including wireless access technologies due to the greater difficulties of the wireless environment and the application of different technologies that have evolved and continue to evolve in order to meet the different difficulties of different environments and different uses.

In a preferred embodiment of the invention, it is applied to radio communications, that is, access technologies that are radio access technologies, RAT. When applied to a radio communications system, the MTA admission control is preferably located in the same situation as a radio network controller of the radio communications system. The admission control of the various individual access technologies is preferably located in a radio network controller or an access point of the radio communication system.

The invention also applies to other wireless communications than radio communications, for example infrared communications and ultrasonic communications, provided there is a plurality of access technologies of communication interest.

It is not intended that the invention be limited only to the embodiments described in detail above. Changes and modifications can be made without leaving the invention. It covers all modifications within the framework of the following claims.