JP3486901B2 - Wireless access system and wireless access method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless access system and a wireless access method, and more particularly to MT-2.
Wireless access system and a wireless access method in which priority is positively given in the H.000 system.

[0002]

2. Description of the Related Art In an MT-2000 system, downlink code management is performed by a base station controller (Radio Network Controller:
RNC). The base station control device provides a priority service such as a best effort service. The priority service is a service that provides preferential handling to an outgoing call from a specific number (incoming call to a specific number) by selecting a communication path in the network. In general, there are two types of priority services: calling from a priority terminal that can be preferentially handled for all calls at any time and receiving a call to a specific emergency number (police station, fire station, etc.). . The best-effort service is a service in which the traffic throughput changes according to the number of users connected to the network.If the channel is vacant, the user can obtain a throughput close to the maximum speed, but when the channel is busy, the throughput is It is a declining service form and has an image similar to the Internet connection form.

Since the radio resource (scrambling code, channelization code) of the cell of the base station is limited, the radio resource becomes insufficient as the user traffic for communicating with the cell increases. In such a situation, when a priority call occurs, even if there are sufficient wired resources (ATM connection, accompanying hardware devices, etc.), the wireless resources are insufficient and the wireless access bearer cannot be established. . As a result, the call is lost even though it is a priority call, or the radio access bearer for the priority call is established after the low priority call is released.

It is required to be able to establish a radio access bearer that supports the information transfer rate required by the priority call without causing both the priority call and the low priority call to be lost.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to establish a radio access bearer that supports the information transfer rate required by a priority call without causing both priority calls and low priority calls to be lost. (EN) Provided are a wireless access system and a wireless access method. Another object of the present invention is to provide a radio access system and a radio access method that enable a radio access bearer service by preferentially assigning a channelization code to a priority call.

[0006]

Means for solving the problem Means for solving the problem are expressed as follows. The technical matters appearing in the expression are accompanied by parentheses (), and numbers, symbols and the like are added. The numbers, symbols and the like are technical matters constituting at least one embodiment or plural examples of the embodiments or plural examples of the present invention, particularly the embodiment or examples. It corresponds to the reference numbers, reference symbols, etc. attached to the technical matters expressed in the drawings corresponding to. Such reference numbers and reference symbols clarify correspondences and bridges between the technical matters described in the claims and the technical matters of the embodiments or examples. Such correspondence / bridge does not mean that the technical matters described in the claims are limited to the technical matters of the embodiment or the examples.

In the radio access method according to the present invention, when a call occurs, a first spreading coefficient satisfying an information transfer rate required for the call is calculated, and a first channelization code corresponding to the first spreading coefficient is calculated. Allocating to the call, storing the first spreading coefficient and the first channelization code at each allocation, and if a priority call occurs, assigning a second spreading coefficient corresponding to the information transfer rate of the priority call. Calculating and assigning a second channelization code corresponding to the second spreading factor to the priority call. Since the channelization code is preferentially assigned to the priority call, it is possible to give priority and high-speed transferability to the priority call, enable the call radio access bearer service, and establish the radio access bearer. it can.

If a second channelization code cannot be assigned to a priority call, a search for a low priority call using a third channelization code corresponding to the same spreading factor as the second spreading factor is performed, 2. If there are one or more low priority calls, then two or more fourth channelization codes corresponding to a spreading factor n (n is an integer greater than or equal to 2) times the second spreading factor of the low priority call. Allocating to the above low priority call and allocating the third channelization code used by the low priority call to the priority call are further added. Priority calls are given priority and fast transfer, and low priority calls are not lost.
After the end of the priority call, the two lower priority calls are returned to the original third
Channelization codes are reassigned. Low priority calls can receive best effort service.

The channelization code has a tree structure in which the numbers increase in the downward direction, and the tree structure is
It has a plurality of layers, and the channelization code of the m-th layer of the plurality of layers is 0, 1, 2, ..., N,
... 2m-1 2m codes are formed, and the channelization code of the (m + 1) th layer of the plurality of layers is n of the channelization code of the mth layer.
2n, 2n + 1 (3n, 3n + 1, 3n +
2, ...). The channelization code has a tree structure in which the numbers increase in the downward direction,
The tree structure has a plurality of layers, and the channelization code of the m-th layer among the plurality of layers is 0, 1,
2, ..., N, ..., 2m−1 of 2m codes are formed, and the channelization code of the m−1th layer of the plurality of layers is the channelization code of the mth layer. Corresponding to n in (n-1) / 2, or
It is n / 2. Such a channelization code numerically corresponds to the high-speed transfer rate, and the creation of the table when giving a priority high-speed transfer rate of 2, 3, 4, ... It can be surely executed, and tree structure multiplication is easily realized.

A radio access system according to the present invention comprises a mobile station (1), a plurality of base stations (2) wirelessly connected to the mobile station (1), and a base station (2) connected to the base station (2). ), A radio base station control device (3), an exchange (4) connected to the radio base station control device (3), and a telephone network (5) connected to the exchange (4), The radio base station control device (3) includes a call control unit (9) for establishing and releasing a radio access bearer, a call information management unit (8) bidirectionally connected to the call control unit (9), and a call control unit. A downlink code management section (11) bidirectionally connected to the section (9), and an SF calculation section (12) connected to the downlink code management section (11),
The call control unit (9) is connected to the SF calculation unit (12), the call information management unit (8) stores information about the call, and the downlink code management unit (11) manages the downlink channelization code. , The SF calculation unit (12) calculates a spreading factor (SF) that satisfies the information transfer rate required by the originating call, the downlink channelization code is formed by a tree structure, and the lower downlink channelization code is generated. Corresponding to the larger spreading factor of the call, the call control unit (9) assigns the higher downlink channelization code to the priority call of the generated call having higher priority.

The information management unit (8) stores a cell information table (1) for storing information on the cell (23) of the base station (2).
3), the cell information table (13) has a scrambling code (16) and a spreading coefficient (18) for each cell.
And the downlink channelization code (the portion of the tree structure formed by the downlink channelization code 19) are stored, and the first spread coefficient that satisfies the information transfer rate required for the outgoing call is calculated by the SF calculation unit (12). The first downlink channelization code corresponding to the first spreading factor is assigned to the generated call by the call control device (9) based on the cell information table (13). The first downlink channelization code is stored in the cell information table (13).

When a priority call occurs, the second spread coefficient corresponding to the information transfer rate of the priority call is calculated by the SF calculation unit (12), and the second downlink channelization code corresponding to the second spread coefficient is set to the call control unit. Assigned to a priority call by. If the second downlink channelization code cannot be assigned to the priority call, a search for a low priority call using the third downlink channelization code corresponding to the same spreading factor as the second spreading factor is performed and two Or 2 or more low priority calls, the second spreading factor of the low priority call is 2
The fourth downlink channelization code corresponding to the double spreading factor is assigned to the two low-priority calls, and the third downlink channelization code used by the low-priority call is assigned to the priority call. The downlink channelization code has the tree structure described above.

According to the present invention, even in such a situation in which the radio resources are insufficient, neither the priority call nor the low priority call is lost, and the radio access capable of supporting the information transfer rate required by the priority call is supported. It is possible to establish a bearer, and the base station controller in the IMT-2000 system gives priority to priority services such as priority calls and emergency calls over low priority services such as best effort services. Radio Access Bearer Service (RA) by dynamically assigning a channelization code.
B) can be provided.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Corresponding to the figures, an embodiment of a radio access system according to the present invention is a plurality of mobile stations (User Equipment: User Equipment) in a general mobile communication system.
UE) is located. As shown in FIG. 1, the mobile station 1 is individually connected to a plurality of radio base station devices (NodeB) 2 each having a cell structure. The mobile communication system constitutes the radio base station control device 3. The radio base station control device 3 controls the base station device 2. Mobile switching center of a mobile communication system (Core Network: C
N) 4 performs the switching operation of the mobile switching network. Mobile switching center 4
Is connected to the telephone network 5.

FIG. 2 shows details of the base station controller 3. The base station control device 3 includes a network 6 that connects the mobile exchanges of the mobile switching center 4 and a control device 7 that controls the mobile exchange. The control device 7 manages a call information management unit 8 that stores information about a call, a call control unit 9 that establishes and releases a radio access bearer for a call, and a downlink scrambling code and a downlink channelization code. And a spreading code (Spreading Factor) for a given information transfer rate.
: SF) is included in the SF calculation unit 12. The call control unit 9 is connected to the SF calculation unit 12, the SF calculation unit 12 is connected to the downlink code management unit 11, and the downlink code management unit 11 is bidirectionally connected to the call control unit 9. The call information management unit 8 is bidirectionally connected to the call control unit 9.

FIG. 3 shows the details of the call information management unit 8. The call information management unit 8 includes a cell information table 13 that stores information about cells. Cell information table 1
3 is composed of a primary list 14 and a secondary list 15. The secondary list 15 forms a table of attributes of a scrambling code 16, a spreading coefficient 18, a channelization code 19, a call number 21, and a call type 22 for each cell. In the call category 22, low priority calls are stored as 0 and calls other than low priority calls are stored as 1 such as best effort calls.

FIG. 4 shows a code numbering tree (Code numbering tree).
Numbering Tree) and downlink channelization codes that can be paid out, a numbering system of downlink scrambling code / channelization code is shown. A downlink code numbering tree is defined for each downlink scrambling code. The cell 23 shown in FIG. 1 can have a plurality of scrambling codes, and the maximum value of the scrambling code is represented by pmax. Here, a certain downlink channelization (code type = m, code number =) in a certain downlink scrambling code (code number = p)
In n), the code number is defined as follows between the “parent” downlink channelization code that exists above it and the code type of the “child” downlink channelization code that exists below it.

Code type of "parent" downlink channelization code: m-1 Code number: (n-1) / 2, if n is odd, n / 2, i
fn is even "Child" Downlink channelization code type: m + 1 Code number: 2n, 2n + 1

Further "parents" or more of the "parent" downstream channelization code are called "ancestor" downstream channelization codes, and further "child" or less of the "child" downstream channelization code are "descendants" downstream channelization. Called the code. If the downlink channelization code type = 0, then there is no "parent" downlink channelization code. When assigning the downlink channelization code, the payable downlink channelization code “X” (code type =
m, code number = n) is selectively defined as follows.

(1) Downlink channelization code X
Has not been paid out. (2) "Ancestor downstream channelization code (parent, parent's parent, ...)" of downlink channelization code X
However, neither is paid out. (3) The “descendant downstream channelization code (child, grandchild, ...)” of the downstream channelization code X is
None have been paid out.

When a call occurs, the mobile switching center 4 requests the base station controller 3 to establish a radio access bearer. The spreading factor is calculated by the SF calculator 12 so as to satisfy the information transfer rate required by the call.
The channelization code type can be uniquely obtained from the spreading coefficient, and the downlink code management unit 11 allocates four channelization codes that can be paid out. In the call information management unit 8, for each code allocation,
The scrambling code 16, the spreading coefficient 18, the channelization code 19, the call number 21, and the call type 22 assigned to the communicating cell are stored.

Similarly, when a priority call occurs, the SF calculation unit 12 calculates the spreading coefficient so as to satisfy the information transfer rate, and the downlink code management unit 11 can pay out the spreading coefficient. However, if the payable channelization code is not assigned, the call control unit 9 executes the algorithm shown in FIG.

It is determined whether a code can be assigned to the priority call (step S1). If a code can be assigned to a priority call, this algorithm immediately completes normally, but if a code cannot be assigned, a channel for the same spreading factor as that of the priority call is used. Whether there is a low priority call using the activation code is searched by the primary list 14 and the secondary list 15 of the cell information table 13 (step S2), and then there are two or more low priority calls. It is determined whether or not to do it (step S). If there are less than two low priority calls, the algorithm terminates and code allocation fails. When there are two or more low priority calls, the downlink channelization code used by the low priority calls is set to i, j (i <j) (step S4). A call using the i (whose call number is Ci) is reallocated to the channelization code 2i, and a call that uses that j (whose call number is Cj). , The channelization code 2i + 1 is reassigned (step S5), and j released by Cj is assigned to the priority call (step S6).

Example: FIGS. 6 and 7 show an example of this embodiment. Chip rate 4.096 Mcps
16 kbps (the symbol rate is 32 kbp) as the information transfer capability (bit rate) required for downlink transmission.
When a priority call requesting s) (call number 700) occurs, the SF calculation unit 12 calculates the spreading coefficient as 256. When the downlink code is not assigned to the spreading coefficient by the downlink code management unit 11, a low priority call using the downlink channelization code for the spreading coefficient 256 is stored in the cell information table 13 of the call information management unit 8. The search is done. As a result, the downlink code i = 4 (call number Ci = 211) and j = 7 (call number Cj = 314) are detected. FIG. 6 shows a downlink code numbering tree before the implementation of this algorithm.

In this algorithm, the downlink code 2 × i = 8 is reassigned to the call number Ci = 211 which is a low priority call, and the downlink code 2 × i + 1 = 9 is reassigned to the call number Cj = 314. , Assign code j = 7 to priority calls. FIG. 7 shows the downlink code numbering tree after the implementation of this algorithm. After the execution of this algorithm, the call information management unit 8 stores the relationship between the priority call and the low priority call number (Ci, Cj) for which the code is rearranged and the downlink code, and stores the priority call when the priority call is released. , The original downlink code is assigned to the low priority call.

As described above, in the base station control device, when a priority call occurs and a channelization code satisfying the information transfer rate cannot be assigned, a low priority call such as a best effort service is temporarily slowed down. By assigning the channelization code, it is possible to establish a radio access bearer capable of supporting the information transfer rate requesting the priority call without causing both the priority call and the low priority call to be lost.

[0027]

The radio access system according to the present invention comprises:
You can proactively apply priority. In particular, it is possible to establish a radio access bearer that supports the information transfer rate required by the priority call without causing both the priority call and the low priority call to be lost.

[Brief description of drawings]

FIG. 1 is a system block diagram showing an embodiment of a wireless access system according to the present invention.

FIG. 2 is a circuit block diagram showing details of a portion shown in FIG.

FIG. 3 is a table showing a cell information table.

FIG. 4 is a tree diagram showing a hierarchical structure of channelization codes.

FIG. 5 is an operation flow diagram showing an embodiment of a wireless access method according to the present invention.

FIG. 6 is a tree diagram showing an example of a tree structure.

FIG. 7 is a tree diagram showing changes in the tree structure.

[Explanation of symbols]

1 ... Mobile station 2 ... Base station 3 ... Radio base station controller 4 ... Exchange 5 ... Telephone network 8 ... Call information management unit 9 ... Call control unit 11 ... Downlink code management unit 12 ... SF calculator 13 ... Cell information table 16 ... Scrambling code 18 ... Diffusion coefficient 19 ... Channelization code 23 ... cell

Claims (10)

(57) [Claims] 1. When a call occurs, calculating a first spreading factor satisfying an information transfer rate required for the call; assigning a first channelization code corresponding to the first spreading factor to the call. Storing the first spreading factor and the first channelization code for each assignment; calculating a second spreading factor corresponding to the information transfer rate of the priority call if a priority call occurs. and to assign a second channelization code corresponding to the second diffusion coefficient in the priority call, assign the second channelization code in the priority call
If it cannot be assigned, it is the same as the second diffusion coefficient
Third channelization code corresponding to the spreading coefficient of
Search for a low priority call that is using, if there are two or more low priority calls, then the low priority call is used.
N of the second spreading coefficient of the previous call (n is 2 or an integer larger than 2)
Number 4) 4th channelization corresponding to diffusion coefficient
Assign a code to two or more low priority calls
, Said low priority call was using the third Chaneraizeshi
6. The wireless access method according to claim 1 , further comprising assigning an application code to the priority call . Wherein after said call priority call termination, further radio access method according to claim 1, comprising re-allocating the original of the two in the low priority call third channelization code. 3. The radio access method according to claim 1 , wherein the low-priority call is a best effort service call. 4. The channelization code has a tree structure in which the numbers increase in the downward direction, and the tree structure has a plurality of layers, and the m-th layer of the plurality of layers has a channelization code. Is 0, 1, 2, ..., N, ..., 2m−
2m number of codes of 1 is formed, and the channelization code of the (m + 1) th layer of the plurality of layers has 2n, 2n + 1 corresponding to the n of the channelization code of the mth layer. The wireless access method according to claim 1 . 5. The channelization code has a tree structure in which the numbers increase in the downward direction, the tree structure has a plurality of layers, and the m-th layer of the plurality of layers has a channelization code. Is 0, 1, 2, ..., N, ..., 2m−
2m number of codes of 1 is formed, and the channelization code of the m-1th layer of the plurality of layers corresponds to the n of the channelization code of the mth layer, and is (n-1 ) / 2, or, the radio access method according to claim 1 which is n / 2. 6. A mobile station, a plurality of base stations wirelessly connected to the mobile station, a radio base station controller for connecting to the base station to control the base station, and a radio base station controller. A switching center to be connected, and a telephone network connected to the switching center, wherein the radio base station control device is a call control unit for establishing and releasing a radio access bearer, and is bidirectionally connected to the call control unit. A call information management unit, a downlink code management unit bidirectionally connected to the call control unit, and an SF calculation unit connected to the downlink code management unit, wherein the call control unit is connected to the SF calculation unit. However, the call information management unit stores information about a call, the downlink code management unit manages a downlink channelization code, and the SF calculation unit is a spreading coefficient that satisfies an information transfer rate required by an originating call. And calculate The downlink channelization code is formed by a tree structure, the lower downlink channelization code corresponds to a larger spreading factor of the generated call, and the call control unit is configured to give priority to the generated call with a higher priority. the downlink channelization code of the higher equivalent to Ri split <br/> by the information management unit, serial information about cells of the base station
A cell information table 1 to be stored is provided, and the cell information table is used for scrambling
Code, spreading factor, downlink channelization code
And a first extension which stores the information transfer rate and satisfies the information transfer rate required for the originating call.
A dispersion coefficient is calculated by the SF calculation unit, and a first downlink channelization corresponding to the first spreading coefficient is performed.
Code is generated based on the cell information table.
Allocation to a call is performed by the call control device , and the first spreading factor and the first downlink are allocated for each allocation.
The channelization code is the cell information table
Wireless access system stored in . 7. When a priority call occurs, a second spreading coefficient corresponding to the information transfer rate of the priority call is calculated by the SF calculation unit, and a second downlink channelization code corresponding to the second spreading coefficient is calculated. 7. The radio access system according to claim 6 , wherein the call control unit assigns the priority call. 8. A low priority call using a third downlink channelization code corresponding to the same spreading factor as the second spreading factor if a second downlink channelization code cannot be assigned to the priority call. If a search is performed and there are two or more low-priority calls, a fourth downlink channelization code corresponding to a spreading factor twice the second spreading factor of the low-priority calls is the two of the low-priority codes. assigned to the call, claim wherein the low priority call was using third downlink channelization code is allocated to the priority call 7
Wireless access system. 9. The downlink channelization code has a tree structure whose number increases in the downlink direction, the tree structure has a plurality of layers, and the m-th layer of the plurality of layers has a downlink channel structure. The activation code is 0, 1, 2, ..., N, ..., 2
2m number of m-1 codes are formed, and the downlink channelization code of the (m + 1) th layer of the plurality of layers corresponds to the n of the channelization codes of the mth layer of 2n, 2n + 1.
The wireless access system according to claim 8 , further comprising: 10. The channelization code has a tree structure in which the numbers increase in the downlink direction, the tree structure has a plurality of layers, and the m-th layer of the plurality of layers has a channelization code. Is 0, 1, 2, ..., N, ..., 2m−
2m number of codes of 1 is formed, and the channelization code of the m-1th layer of the plurality of layers corresponds to the n of the channelization code of the mth layer, and is (n-1 ) / 2, or a wireless access system of claim 8 which is n / 2.