RU2375847C2 - METHOD FOR DYNAMIC ALLOCATION OF TIME INTERVALS IN Abis INTERFACE OF MOBILE COMMUNICATION SYSTEM - Google Patents

Abstract

FIELD: physics; communications.

SUBSTANCE: invention relates to mobile communication systems. Disclosed is a method for dynamic allocation of time intervals for transmission in an Abis interface of a mobile communication system, involving the following steps: establishing the minimum time interval as a basic element of a land channel for the Abis interface and the main time interval and a group of backup resources is established, where the time intervals of the group of backup resources are additional time intervals; priority levels are set for each service of the system, requesting additional time intervals; when any service of the system requires a large number of time intervals for the Abis interface, additional time intervals are requested and the said group of backup resources decides on allocating additional time intervals depending on the priority level of the service and the current state of the backup resource; occupied additional time intervals are freed up and are returned to the group of backup resources for the next use, if the services of the system no longer require excess number of time intervals for the Abis interface. Also disclosed is a device for realising the said method.

EFFECT: invention increases efficiency of utilising time intervals for the Abis interface and maximal satisfaction of demand for services.

10 cl, 5 dwg

Description

Technical field

The present invention relates to the field of mobile communications, in particular to a method for dynamically allocating transmission time slots of an Abis interface of a mobile communication system in accordance with various service rates.

State of the art

Communication systems play an ever-increasing role in public life. The growing demand for communication services is stimulating the rapid development of communication technologies, in particular the mobile communication system, which has rapidly evolved from the traditional Global GSM System for Mobile Communications (GSM) to the General Purpose Packet Radio Communication System (GPRS). In order to provide higher throughput to meet the requirements of various real-time packet services, the Advanced PRON System (GPRS) - UPRON (EGPRS) has also been developed: on the other hand, since the number of subscribers to the GSM system is is constantly growing, operators require an increasing number of voice services at Half Speed PVS (HR) to provide voice services to more subscribers without an excessive increase in investment. In particular, the system is required so that it can automatically convert full-speed PS (FR) channels to PVA (HR) channels at different time periods to provide more channels, or combine PVA (HR) channels into PS (FR) channels to provide more high quality transmission.

A typical GSM subsystem base station subsystem structure is shown in Figure 1. In Figure 1, the BSC (BSC) is the Base Station Controller, the BTS (BTS) is the Base Transceiver Station, and the CCU (CCU) is the Channel Coding Block. The BTS station (BTS) maps the air interface (Um) to the Abis interface of the terrestrial channel between the BTS station (BTS) and the BSC controller. In the GSM system, a channel time interval of 16 kbit / s is used as the minimum unit element on the Abis interface. Thus, since in the original GSM system, when transmitting voice and packet services over the Um channel, the service channel Um speed does not exceed 16 kbit / s, the Um channel and the 16 kbit / s time interval of the Abis interface are displayed one to one. However, in the UPRON system (EGPRS), in which the Um channels are used for packet services, different encoding and modulation methods are used, and the speeds also differ, as shown in Table 1. If the MCS-3 ~ MCS-9 encoding methods are used, it is necessary so that the Um channel corresponds to 2 to 5 time slots of the Abis interface.

Table 1 Coding and modulation scheme Maximum speed: [kbps] MCS-9 59.2 Mcs-8 59.2 MCS-7 44.8 Mcs-6 29.6 Mcs-5 22.4 Mcs-4 17.6 Mcs-3 14.8 Mcs-2 11,2 MCS-1 8.8

Currently, the following method is being used to solve this problem: first, a packet service channel Um is created that corresponds to the channel time interval of the Abis interface, at the same time, part of the time intervals of the Abis interface is allocated for use as a backup resource when the bandwidth required for the service channel exceeds one time interval of the Abis interface; in this case, again, one or more time slots from the backup resource are allocated for mapping to this packet service channel Um. For example, in Chinese Patent Application No. 01126612.0, “General Method for Transmitting a Wireless Packet Service Data Frame Signal,” the above solution is applied to CS-3 and CS-4 packet services in a PRON service (GPRS).

The disadvantage of this method is that the backup resource is used only for packet services, and its use for all services is not considered as a universal method. The Abis interface channel resource should be used not only for packet services, but, more importantly, for processing voice services. In the GSM system, the goal of operators is to provide subscribers with the maximum amount of services using limited resources. Therefore, a further increase in the degree of use of resources and an improvement in the quality of service delivery is possible only if the backup resource of the Abis interface is fully used, depending on the current needs of all system services.

In the case of the voice service of the PVA (HR), the primary service channel Um can be converted into two service channels supporting the PVA (HR). In fact, a bandwidth of 8 kbit / s is sufficient to provide one channel of the voice service of the PVA (HR). However, since the minimum channel time interval of the Abis interface is usually 16 kbps, the existing method for supporting PVA (HP) is as follows: when the primary service channel Um supporting the MS (FR) is converted into two service channels supporting PVA (HR), the Abis interface requires two time slots that can only be used by two voice services of the PVS (HR), which causes unproductive use of the resources of the Abis interface. Since at the same time a part of the Abis interface time interval resource is used as a backup resource for packet services, the Abis interface time interval resource is essentially insufficient, and the number of channels that can be converted into PVA channels (HR) is significantly limited.

It can be seen from the above description that, since the current state of the art, various services, for example voice and packet, are considered out of touch with each other, this leads to a disadvantage in terms of the low resource utilization of the Abis interface.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a method for sharing and dynamically allocating a backup resource of time slots of an Abis interface in such a way as to ensure full and efficient use of resources of the Abis interface.

To accomplish this task, the resources of the time intervals of the Abis interface in the present invention are divided into two parts: the main time interval and the group of backup resources, while the main time interval is a single time interval in which the primary service channel Um is mapped to the Abis interface, and by the group reserve resources are understood as all other time intervals of the Abis interface, while the time intervals in the reserve resource group are defined as additional time intervals. If a certain service of the system requires a larger number of time intervals, it contacts the group of backup resources, regardless of what kind of service it is. In this method, application priority levels of various services, for example voice services and packet services, are set so that the reserve resource group can satisfy the requirements of each type of service in accordance with their priority levels.

According to the above, on the one hand, the present invention provides a method for dynamically allocating transmission time slots for an Abis interface of a GSM system, consisting of the following steps:

Step 1, set the minimum time interval as a basic element of the Abis interface channel overhead, establish a correspondence between the service channel part Um and the time interval part of the Abis interface, and determine the time interval as the main time interval; define part or all of the free time slots of the Abis interface as a group of reserve resources, while the time intervals in the group of reserve resources are additional time intervals;

Step 2, request additional time intervals from the mentioned reserve resource group in the event that any of the system services needs more Abis interface time intervals, while the specified reserve resource group decides on the allocation of additional time intervals depending on the status of the reserve resources ; and

Step 3, release the occupied additional time slots and return them to the reserve resource group for later use if the system services no longer need the excessive number of time slots of the Abis interface.

In accordance with the method of the present invention, between Step 1 and Step 2, a step of establishing a priority level of each system service is introduced to request additional time slots; in the aforementioned Step 2, when the specified group of reserve resources makes a decision on the need for additional time intervals, it also determines the sequence for providing additional time intervals in accordance with the priority level of each service.

In accordance with the method of the present invention, in simplified processing, all priority levels of various services of said system for requesting the use of additional time slots are set to the same.

In accordance with the method of the present invention, if the system allocates an additional time interval from said reserve group for a certain type of service, this additional time interval assumes the status of “dedicated”, and the base transceiver station BTS (BTS) is informed about the correspondence between the channel Um and the additional time Abis interface interval.

According to the method of the present invention, if in step 3 the system returns the released additional time interval, this additional time interval assumes the status of “unallocated”, and the BTS (BTS) is informed that the service channel Um no longer corresponds to any additional time interval .

On the other hand, the invention provides a device for allocating a resource of time intervals for an Abis interface of a GSM system, consisting of a base station controller BSC (BSC), BTS (BTS) and an Abis interface connecting BSC (BSC) and BTS (BTS), this as a basic element of the Abis interface take the minimum time interval; the device also contains a module for determining the main time interval and a group of reserve resources, which is used to determine the time interval of the Abis interface corresponding to the service channel Um as the main time interval, and other free time intervals of this Abis interface as a group of reserve resources, time slots in said reserve resource group are additional time slots; an additional time interval request module, which is used to decide whether to allocate additional Abis interface time interval resources to a particular type of system service and request, if necessary, additional time intervals from a reserve resource group; a module for providing additional time intervals, which is used to decide on the provision of additional time intervals in accordance with the state of the reserve resource, when various services of the system request additional time intervals from the group of reserve resources; as well as a module for disposing of additional time intervals, which is used to utilize additional time intervals provided for services and return them to the reserve resource group for later use when system services no longer need excessive time intervals of the Abis interface.

The device in accordance with this invention includes, in addition, a module for setting priority levels, which serves to determine the priority level of each service provided by the system, to request additional time intervals; the above additional time slot providing module determines the sequence of providing additional time slots in accordance with the priority level of each service when additional time slots can be provided.

According to the apparatus of the present invention, in simplified processing, said priority setting module sets all priority levels of requesting additional time intervals for the various services provided by the system to the same.

In accordance with the device of the present invention, if the specified module for the provision of additional time intervals allocates an additional time interval from the mentioned group of reserve resources for a certain type of service, this additional time interval assumes the status of "allocated", and BTS (BTS) is informed about the correspondence between the channel Um and additional time interval of the Abis interface.

According to the apparatus of the present invention, if said additional time slot utilization module returns a released additional time interval, this additional time interval assumes an “unallocated” status, and the BTS is informed that the service channel Um no longer corresponds to any additional time interval .

Since a group of reserve resources is based on each ground channel of the Abis interface, each additional time interval from a group of reserve resources of one ground channel can be dynamically used in conjunction with the main time interval of a given ground channel.

Using the above scheme, the invention provides the following advantages:

1. a significant increase in the degree of use of ground resources and the maximum satisfaction of system requirements;

2. Increasing flexibility in the use of resources and better satisfying the needs of subscribers as a result of the sharing of Abis interface ground resources in accordance with service priority levels; as well as

3. ensuring the maximum possible number of voice services of the PVS (HR) based on existing hardware.

Description of figures

Figure 1 schematically shows the location of the Abis interface in a mobile communication system.

Figure 2 is a schematic diagram illustrating the dynamic use by different services of additional time slots in accordance with the method of the present invention using, as an example, voice and packet services.

Figure 3 is a schematic diagram of an algorithm for requesting additional time slots from a group of spare resources in accordance with a method for allocating a resource of time slots of an Abis interface in a mobile communication system in accordance with the present invention.

Figure 4 is a schematic diagram of an algorithm for returning additional time slots to a group of backup resources in accordance with a method for allocating a resource of time slots of an Abis interface in a mobile communication system in accordance with the present invention.

5 is a block diagram of an Abis interface slot allocation device in a mobile communication system in accordance with the present invention.

Preferred implementation of the invention

The following description of the present invention will be made taking into account the attached figures.

Figure 2 is a schematic diagram illustrating the dynamic use by different services of additional time slots in accordance with the method of the present invention using, as an example, voice and packet services. As shown in FIG. 2, the Abis interface time interval resource is divided into the main time interval and the backup resource group, while the Abis interface time interval to which the voice channels PS (FR) and PVS (HR) Um are displayed is the main time interval A and other time intervals are in the reserve resource group A ′ as additional time intervals. If a certain system service requires a larger number of time intervals, it contacts the reserve resource group A ′, regardless of what kind of service it is. Upon reaching a certain level of losses in the voice channel, it will be necessary to increase the capacity of the voice channel, i.e. one voice channel PS (FR) Um is converted into two voice channels PVA (HR). As an alternative to the packet service, if the wireless environment satisfies the condition of good enough transmission quality, and the system decides to transmit the wireless channel corresponding to point A with encoding of MCS-3 level or higher, additional time intervals will be requested from the reserve resource group; In this method, application priority levels for various services, such as voice and packet services, are set so that the reserve resource group can satisfy the requests of each type of service in a sequence corresponding to priority levels.

Figure 3 is a schematic diagram of an algorithm for requesting additional time slots from a group of spare resources in accordance with a method for allocating a resource of time slots of an Abis interface in a mobile communication system in accordance with the present invention. Figure 3 provides a detailed description of the procedure for extending the time slots of the Abis interface by the system, for example, when one channel should receive additional intervals of the Abis interface; The procedure includes the following steps:

Step S31: the system determines the point A of the Abis interface in advance as the main time interval, i.e. corresponding to the wireless channel, and defines other free time intervals as a group of reserve resources;

Step S32: a decision is made whether some kind of system service requires additional time slots of the Abis interface to provide more services when, for example, voice channel losses increase to a level requiring an increase in voice channel capacity, i.e. the conversion of one channel PS (FR) Um in two voice channels PVA (HR); or if, in the case of the packet service, the wireless medium satisfies the condition of good enough transmission quality, and the system decides to transmit the wireless channel corresponding to point A with encoding of MCS-3 level or higher, and, if so, performs step S33 ;

Step S33: a reserve resource group is requested to allocate one or more additional time intervals;

Step S34: the reserve resource group decides to allocate additional time intervals in accordance with the application priority level and the backup resource busy state; in the event of a failure, the allocation of intervals does not occur and the procedure ends; when the additional time interval A 'is allocated, a transition occurs to step S35;

Step S35: for this time interval, the status is “allocated” in order to avoid re-allocation of the time interval to other wireless channels; and

Step S36: correspondence information between the wireless channel and points A and A ′ is sent to the BTS, after which the whole procedure completes normally.

Figure 4 is a schematic diagram of an algorithm for returning additional time slots to a reserve resource group in accordance with a method for allocating a time slot resource of an Abis interface in a mobile communication system in accordance with the present invention. Figure 4 provides a detailed description of the procedure for returning additional time slots of the Abis interface by the system, for example, when the wireless channel no longer needs additional time slots of the Abis interface; The procedure includes the following steps:

Step S41: the system already uses the main time interval of point A and the additional time interval of point A 'of the Abis interface;

Step S42: the packet service starts using coding of the MCS-1 or MCS-2 level instead of the MCS-3 level or higher, and the reserve resource group is informed about resource utilization when some kind of system service no longer needs the extended resources of the Abis interface time slots, for example, as a result of a decrease in demand for voice services or a deterioration in the wireless environment;

Step S43: the reserve resource group recycles the additional time interval of point A ';

Step S44: for the disposable additional time interval of point A ′, the status is “unallocated” so that the time interval can again be allocated to other wireless channels; and

Step S45: The BTS is informed that the service channel Um does not correspond to the additional time interval of point A ', after which the whole procedure completes normally.

5 is a block diagram of a best implementation of an Abis interface slot allocation device in a mobile communication system in accordance with the present invention. In this figure, the Abis 520 interface is installed between the BSC (BSC) 510 and the BTS (BTS) 580 and is divided into many time intervals with a minimum time interval as a base element. As shown in the figure, the Abis interface time resource allocator in accordance with the present invention also includes: a main time interval module and a reserve resource group 530, which is used to determine an Abis 520 interface time interval corresponding to the service channel Um as the main time interval , and defining other free time slots of the Abis 520 interface as a reserve resource group, while the time slots in the reserve resource group are I have extra time intervals; module 540 setting the priority level, which is used to determine the priority level of each service provided by the system, to request additional time intervals, but with simplified processing, the priority levels of each service provided by the system to request additional time intervals can be set the same; module 550 request additional time intervals, which is used to decide on the need for additional resources for the time intervals of the Abis interface for a certain type of service of the system and access the group of backup resources for additional time intervals if necessary; module 560 provide additional time intervals, which is used to decide on the provision of additional time intervals in accordance with the state of the reserve resources when various services of the system contact the group of reserve resources for additional time intervals, as well as to determine the sequence of the provision of additional time intervals in accordance with priority levels of each service in case of decision on the provision of additional temporary ntervalov. If the module 560 provide additional time intervals allocates an additional time interval in the mentioned group of reserve resources for the type of service, this additional time interval receives the status of "allocated", while the BTS 580 is informed about the correspondence between the channel Um and the additional time interval of the Abis interface; module 570 utilization of additional time intervals, which is used to utilize the additional time intervals provided for the service, and return them to the reserve resource group for subsequent use when the system service no longer needs additional time intervals of the Abis interface, as well as determining the status of "unallocated" for the returned time intervals and informing the BTS 580 that the service channel Um no longer corresponds to any additional th time interval.

The following examples show the effect expected from the use of the method or device in accordance with the present invention.

As an example, consider voice and packet services at a standard S3 / 3/3 type station (i.e., three cells per station, three carriers per cell), with each cell typically configured to support eighteen voice channels of the MS (FR ) and four packet service channels, thus, three cells are allocated (18 + 4) · 3 = 66 channel time slots of the Abis interface (16 kbit / s). The number of time slots of the Abis interface used to control the signaling of a station of this type is at least 10. The total number of time slots provided by a pair of Abis E1 interfaces is 128, the number of time slots used for clock synchronization is 4, thus the final number of time slots intervals that can be used as a backup resource is: 128-66-10-4 = 48. Provided that half of these 48 time slots is fixed for the PVS voice service (HR) and half for packet services, the maximum number of supported voice channels is 18 · 3 + 24 = 78, and the maximum number of time slots used for packet services is 4 · 3 + 24 = 36. However, when using the present invention, all free time slots can be used to support voice or packet services, with the maximum total number of supported voice channels being 18 · 3 + 48 = 102, and the maximum total number of time slots used for packet services is 4 · 3 + 48 = 60.

table 2 Using the invention Maximum number of voice channels (PVA (HP) + PS (FR)) Maximum number of time slots for packet services Primary invention 78 36 The present invention 102 60 Productivity increase (%) 30.8 66.7

From table 2 it is seen that in the case of a limited resource of free channels of the Abis interface, the method of the present invention can further increase the degree of resource use in accordance with the practical needs of the services.

Practical applicability

The present invention is mainly used in a GSM mobile communications system. By dividing the Abis interface time interval resource into a main time interval and a reserve resource group, as well as sharing a group of system resources and allocating resources with full consideration of the current needs of all system services, this provides an additional increase in the use of Abis interface time interval resources and satisfaction of service requirements.

Claims (10)

1. A method for dynamically allocating transmission time slots in an Abis interface of a mobile communication system, comprising the following steps:
step 1 - set the minimum time interval as a basic element of the Abis interface channel overhead, establish a correspondence between part of the service channels Um and part of the time intervals of the Abis interface and define these time intervals as main time intervals: define parts or all free time intervals of the Abis interface as groups reserve resources, while the time intervals in the group of reserve resources are additional time intervals;
step 2 - use additional time intervals from the mentioned reserve resource group in the case when any system service needs more Abis interface time intervals, while the specified reserve resource group decides on the allocation of additional time intervals depending on the state of the backup resource: and step 3 — release the busy additional time slots and return them to the reserve resource group for later use if the system services are no longer spytyvayut need for excessive number of time slots Abis interface. 2. The method according to claim 1, in which between steps 1 and 2 enter the step of establishing the priority level of each system service to request additional time intervals; in said step 2, if the need for additional time intervals is determined, then the specified group of reserve resources additionally determines the sequence of providing additional time intervals in accordance with the priority level of each service. 3. The method according to claim 2, in which, during simplified processing, all priority levels of various services of the said system for requesting additional time intervals are set equal. 4. The method according to any one of claims 1, 2 or 3, in which, if the system allocates an additional time interval from the mentioned group of reserve resources for a certain type of service, this additional time interval takes on the status of "allocated", and the base transceiver is informed of compliance between the Um channel and the additional time interval of the Abis interface. 5. The method according to claim 4, in which, if at the said step 3 the system utilizes the released additional time interval, this additional time interval takes on the status of “unallocated”, and the base transceiver station is informed that the service channel Um no longer corresponds to any additional time interval. 6. A device for dynamically allocating transmission time slots in an Abis interface of a mobile communication system comprising a base station controller, a base transceiver station and an Abis interface connecting a base station controller and a base transceiver station, the minimum time interval being used as the base interface element of the specified Abis interface ; the device also includes: a module for determining the main time interval and a group of reserve resources, which serves to set the time intervals of the Abis interface corresponding to the service channels Um as main time intervals, and other free time intervals of the Abis interface as a group of reserve resources in which time intervals groups of reserve resources are additional time intervals;
a module for requesting additional time intervals, which serves to make a decision on the need to provide an additional resource for the time slots of the Abis interface for this type of service and contact the group of reserve resources for additional time intervals if necessary;
a module for providing additional time intervals, which serves to make a decision on the provision of additional time intervals in accordance with the state of the reserve resources when each service of the system contacts the group of reserve resources for additional time intervals; and
an additional time interval utilization module, which is used to utilize additional time intervals provided to the services and return them to the reserve resource group for later use if the system services no longer need the excessive number of time intervals of the Abis interface. 7. The device according to claim 6, which additionally contains a module for setting priority levels, which is used to determine the priority level of each service provided by the system, to request additional time intervals; moreover, the specified module for the provision of additional time intervals determines the sequence for the provision of additional time intervals in accordance with the priority level of each service, when additional time intervals can be provided. 8. The device according to claim 7, in which, when simplified processing, the specified priority setting module sets the priority levels of all types of services provided by the system to request additional time intervals. 9. The device according to claim 6, in which, if the specified module for the provision of additional time intervals allocates an additional time interval from the mentioned group of reserve resources for a certain type of service, this additional time interval takes on the status of "allocated", and the base transceiver station is informed about the correspondence between Um channel and additional time interval of the Abis interface. 10. The device according to claim 6, in which, if the specified module utilization of additional time intervals utilizes an additional time interval, this additional time interval takes the status of "unallocated", and the base transceiver station is informed that the service channel Um no longer corresponds to any additional time interval.

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