CN1581748A - Interference code allocation method for communication system switch - Google Patents

Abstract

The invention relates to a method for switching between different communication systems in the field of wireless communication, and discloses a method for allocating scrambling codes for switching from GSM to WCDMA, so that uplink scrambling code resources can be utilized to a greater extent, and the success rate of system switching is higher . This scrambling code allocation method for switching from GSM to WCDMA mainly includes the following steps: A radio network controller randomly selects an uplink scrambling code in the scrambling code resource table; B radio network controller judges whether the selected uplink scrambling code has previously Already occupied, if yes, then go to step C, if not, then go to step E; C wireless network controller judges whether the number of times of randomly selected uplink scrambling code exceeds the preset threshold value, if yes, go to step D , if not, go to step A; D. The radio network controller obtains the left uplink scrambling code from the scrambling code resource table; E. The radio network controller allocates the uplink scrambling code to the mobile station.

Description

Scrambling code allocation method for communication system handover

technical field

The present invention relates to a scrambling method for switching between different communication systems in the field of wireless communication, in particular to switching from Global System for mobile Communication (GSM for short) to Wideband Code Division Multiple Access (Wideband Code Division Multiple Access for short). "WCDMA") communication system scrambling code allocation method.

Background technique

In the existing wireless communication technology, when a mobile station such as a mobile phone or a personal digital assistant with mobile communication functions moves from a GSM coverage area to a WCDMA communication system coverage area, it can be completed through a predefined or default handover process switch.

In this case, the Universal Mobile Telecommunications System Terrestrial Radio Access Network (UMTS Terrestrial Radio Access Network, referred to as "UTRAN") is responsible for assigning uplink scrambling codes and other tasks. The current communication protocol stipulates that the scrambling codes from 0 to 8191 are fixedly reserved for this process. Since each mobile station switching from GSM to WCDMA communication system needs to correspond to an uplink scrambling code, therefore, GSM can simultaneously support The number of system switching depends largely on the utilization of uplink scrambling code resources. That is to say, the allocation technology of uplink scrambling code resources will affect the success rate of handover between GSM and WCDMA communication systems.

Among the currently commonly used uplink scrambling code allocation methods, one method is that the radio network controller at the UTRAN side randomly selects an uplink scrambling code from a scrambling code resource table and allocates it to the mobile station. If the uplink scrambling code assigned to the mobile station has already been occupied, the inter-system handover is rejected by the system due to failure in uplink scrambling code assignment.

Another method is based on the above scheme, when the uplink scrambling code assigned to the mobile station is already occupied, the radio network controller retries to assign the uplink scrambling code to the mobile station until the number of retries reaches a predetermined threshold value, In this case, the system handover is rejected by the system because the uplink scrambling code allocation fails.

In practical applications, the above schemes have the following problems: In the first scheme, when the scrambling code resources are tight, for example, a large number of mobile stations perform inter-system handover in a concentrated manner for a period of time, it is easy to fail in the allocation of uplink scrambling codes, thus handover The process rolls back and the system switching fails. In the second scheme, although a retry mechanism is added, multiple retries are allowed when the first allocation of uplink scrambling codes fails, and the switching process is rolled back when the number of retries reaches a predetermined threshold, and the system switching Failed, but this solution still cannot make full use of the limited uplink scrambling resources, resulting in a low success rate of system handover.

One of the main reasons for this situation is that the uplink scrambling code is randomly selected in the scrambling code resource table, and the uplink scrambling code that has been occupied is likely to be selected again, which leads to the failure of the uplink scrambling code allocation and affects the system switching .

Contents of the invention

The technical problem to be solved by the present invention is to provide a scrambling code allocation method for switching from GSM to WCDMA communication system, so that uplink scrambling code resources can be utilized to a greater extent, and the system switching power is higher.

In order to solve the above-mentioned technical problems, the scrambling code allocation method for switching from GSM to WCDMA communication system provided by this party includes the following steps:

A radio network controller randomly selects an uplink scrambling code in the scrambling code resource table as an uplink scrambling code resource allocated to the mobile station, and enters step B;

The B radio network controller judges whether the selected uplink scrambling code has been occupied before, if yes, then enter step C, if not, then enter step E;

The C radio network controller judges whether the number of times of randomly selected uplink scrambling codes exceeds a preset threshold value, if yes, proceeds to step D, and if not, proceeds to step A;

D. The radio network controller obtains the left uplink scrambling code from the scrambling code resource table as the uplink scrambling code resource allocated to the mobile station, and enters step E;

The E radio network controller allocates the uplink scrambling code resources to the mobile station, and updates the state of the corresponding uplink scrambling code resources in the scrambling code resource table to the allocated state.

Wherein, in described step A, also comprise the following steps:

The radio network controller adds 1 to the number of times for selecting the uplink scrambling code.

In said step C, also include the following steps:

The radio network controller adds 1 to the number of times for selecting the uplink scrambling code.

The scrambling code resource table is in the radio network controller.

In addition, the present invention also provides another scrambling code allocation method for switching from GSM to WCDMA communication system, comprising the following steps:

The radio network controller selects all remaining uplink scrambling code resources in the scrambling code resource table, arranges them randomly, and obtains an uplink scrambling code resource allocation sequence;

The radio network controller sequentially acquires the remaining uplink scrambling code resources from the uplink scrambling code resource allocation sequence, allocates them to the mobile station, and updates the state of the corresponding uplink scrambling code resources in the scrambling code resource table to the allocated state;

When the radio network controller acquires all the uplink scrambling code resources in the uplink scrambling code resource sequence, re-randomly sort the remaining uplink scrambling code resources in the said scrambling code resource table to generate a new uplink scrambling code resource Allocation sequence.

Through comparison, it can be found that the difference between the technical solution of the present invention and the prior art is that the radio network controller obtains the left uplink scrambling code from the scrambling code resource table and allocates it to the mobile station.

The difference in this technical solution has brought obvious beneficial effects, that is, since the uplink scrambling code is obtained from the legacy uplink scrambling code resources and allocated to the mobile station, it can avoid the Allocation to the mobile station leads to the failure of the allocation of the uplink scrambling code, which causes the phenomenon that the inter-system handover is rejected, so that the success rate of the system is greatly improved. In addition, due to the method of the present invention, the utilization rate of the legacy uplink scrambling code resource is improved.

Description of drawings

Fig. 1 is a flow chart of main steps of a method for allocating scrambling codes for switching from GSM to WCDMA communication system according to an embodiment of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings.

As shown in Figure 1, in one embodiment of the present invention, at first in step 100, the radio network controller randomly selects the uplink scrambling code in the scrambling code resource table as the uplink scrambling code resource allocated to the mobile station, and then enters the step 200. This step is actually the same as in the prior art. Wherein, the scrambling code resource table is in the radio network controller. The table contains scrambling code resources from 0 to 8191 specified in the communication protocol. Some scrambling code resources have been randomly selected and allocated in the previous scrambling code allocation, and are in the occupied state, while others have not been allocated. is in a legacy state.

In step 200, the radio network controller judges whether the selected uplink scrambling code is occupied, if yes, enter step 300, if no, enter step 500. It should be noted that, in the scrambling code resource table, each scrambling code resource includes a flag for representing the state of the uplink scrambling code resource, that is, whether it is a legacy scrambling code or an occupied scrambling code. The radio network controller judges the status of the selected uplink scrambling code according to this flag.

In step 300, since the radio network controller has determined that the selected uplink scrambling code is already occupied, the selected uplink scrambling code cannot be allocated to the mobile station for switching between systems. In this case, the radio network controller The device judges whether the number of times of randomly selecting uplink scrambling codes exceeds a preset threshold value, if yes, proceed to step 400, and if not, proceed to step 100. Wherein, the accumulation of times of random selection of uplink scrambling codes can be completed in step 100, or in step 300, that is, before the judgment. The threshold value in step 300 is artificially set in advance according to needs, for example, it may be 3 times, or 5 times and so on.

In step 400, when the radio network controller determines that the number of selected uplink scrambling codes exceeds a predetermined threshold, the radio network controller obtains the left uplink scrambling code from the scrambling code resource table as the uplink scrambling code allocated to the mobile station. scrambling resources, and then go to step 500. It should be pointed out here that since the scrambling code allocation in step 100 is random allocation, the legacy scrambling code resources are also randomly distributed, which will not affect the randomness of the uplink scrambling code allocation.

In step 500, the radio network controller allocates the uplink scrambling code resource to the mobile station, and updates the state of the corresponding uplink scrambling code resource in the scrambling code resource table to be occupied, that is, the scrambling code resource table is maintenance, and the whole scrambling code allocation process is over. Since the radio network controller updates the state of the uplink scrambling code resources in the scrambling code resource table in time, the scrambling code resource table can accurately reflect the current state of each uplink scrambling code resource in the table, which is an important factor for the good implementation of the present invention. Base.

In addition, after step 500, the mobile station performs system switching from GSM to WCDMA according to the uplink scrambling code resource allocated to it by the radio network controller. In the present invention, in order to make better use of the uplink scrambling code resources, once the mobile station switches successfully, it immediately re-applies for the uplink scrambling code resources of the WCDMA system, and releases the uplink scrambling code resources in the GSM system after the application is successful. The advantage of doing this is that the uplink scrambling code resource in the GSM system can be restored to the legacy state as soon as possible, so as to be utilized to the greatest extent. On the other hand, after the GSM uplink scrambling code resource is released, the scrambling code resource table in the radio network controller immediately updates the state of the uplink scrambling code resource to the legacy state.

According to the principles of the present invention, another method for allocating uplink scrambling codes is provided: the radio network controller selects all remaining uplink scrambling code resources in the scrambling code resource table, arranges them randomly, and obtains an uplink scrambling code resource allocation sequence. Then, according to the sequence in the sequence, the uplink scrambling codes are allocated to each mobile station in sequence until all the uplink scrambling codes in the sequence are allocated.

At this time, the uplink scrambling code previously allocated to the mobile station is released because the mobile station has applied for the uplink scrambling code of the WCDMA communication system. Therefore, the radio network controller randomly sorts the remaining uplink scrambling codes in the scrambling code resource table, generates a new uplink scrambling code resource allocation sequence, and continues to allocate the legacy uplink scrambling codes to the mobile station, repeating the cycle.

Although the present invention has been illustrated and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein, and without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (5)

1. a scrambling code distribution method that is used for switching to from global system for mobile communications Wideband Code Division Multiple Access (WCDMA) communication system is characterized in that, comprises following steps:

The A radio network controller is the picked at random uplink scrambling code in the scrambler resource table, and the uplink scrambling code resource as distributing to travelling carriage enters step B;

The B radio network controller judges whether the uplink scrambling code that is selected is occupied before this, if, then enter step C, if not, then enter step e;

The C radio network controller judges whether the number of times of picked at random uplink scrambling code surpasses predefined threshold value, if, then enter step D, if not, then enter steps A;

The D radio network controller obtains the uplink scrambling code resource that described travelling carriage is distributed in the uplink scrambling code conduct of leaving over from described scrambler resource table, enter step e;

The E radio network controller is given travelling carriage with described uplink scrambling code resource allocation, and corresponding uplink scrambling code resource status in the described scrambler resource table is updated to distribution state.

2. the scrambling code distribution method that is used for switching to from global system for mobile communications Wideband Code Division Multiple Access (WCDMA) communication system according to claim 1 is characterized in that, also comprises following steps in described steps A:

Radio network controller is that the number of times of choosing uplink scrambling code adds 1.

3. the scrambling code distribution method that is used for switching to from global system for mobile communications Wideband Code Division Multiple Access (WCDMA) communication system according to claim 1 is characterized in that, also comprises following steps in described step C:

Radio network controller is that the number of times of choosing uplink scrambling code adds 1.

4. the scrambling code distribution method that is used for switching to from global system for mobile communications Wideband Code Division Multiple Access (WCDMA) communication system according to claim 1 is characterized in that, described scrambler resource table is in radio network controller.

5. a scrambling code distribution method that is used for switching to from global system for mobile communications Wideband Code Division Multiple Access (WCDMA) communication system is characterized in that, comprises following steps:

Radio network controller is selected all uplink scrambling code resources of leaving in the scrambler resource table, carries out random alignment, obtains uplink scrambling code resource allocation sequence;

Radio network controller obtains the uplink scrambling code resource of leaving over successively from described uplink scrambling code resource allocation sequence, distribute to travelling carriage, and corresponding uplink scrambling code resource status in the described scrambler resource table is updated to distribution state;

When radio network controller has obtained whole uplink scrambling code resource in the described uplink scrambling code resource sequence, again the uplink scrambling code resource of leaving in the described scrambler resource table is carried out randomly orderedly, generate a new uplink scrambling code resource allocation sequence.

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