KR100370058B1 - Fast data service method - Google Patents

Abstract

The present invention relates to a high speed data service method suitable for efficiently allocating an additional channel (SCH) for a high speed data service in a mobile communication system based on a code division multiple access (CDMA) scheme. The high speed data service method of the present invention comprises the steps of: calculating, by a base station (BTS), the number of idle channels that can be allocated to the requested additional channel in a given CDMA channel when an additional channel for data service is requested from a user side (UE); Comparing the calculated size of the idle channel with the number of additional channel allocation limit channels already set, and if the calculated number of idle channels is greater than the number of additional channel allocation limit channels already set, the base station (BTS) When the requested additional channel is allocated or the calculated idle channel number is smaller than the required additional channel number according to the comparison result, the base station BTS determines whether to allocate the requested additional channel under control of the base station controller BSC. By allocating channel resources to voice calls that are in demand more than high-speed data services, A communication service can be provided and the channel allocation time can be shortened by allocating a plurality of additional channels simultaneously for high-speed data service.

Description

Fast data service method

TECHNICAL FIELD The present invention relates to mobile communications, and in particular, to a high speed data service method that is suitable for efficiently allocating an additional channel (SCH) for a high speed data service in a mobile communication system based on a code division multiple access (CDMA) scheme. will be.

In general, current mobile communication systems using the EIA / TIA IS-95A standard provide voice or data services by allocating a radio channel having a data rate of 8kbps or 13kbps to a user.

However, in the IS-95B standard, which is currently being developed for the purpose of commercialization, in order to provide a high-speed data service having a data rate of 64 kbps, in addition to one radio channel allocated according to the IS-95A standard, another wireless channel is requested upon request. To allocate additionally. In this case, a radio channel allocated for the first time is called a fundamental channel (FCH), and when the amount of data to be transmitted other than the basic channel is increased and a fast transmission rate is required, an additional channel is allocated to the additional channel (Supplemental channel). , SCH).

Herein, the present invention focuses on the additional channel (SCH), and the additional channel (SCH) is dynamically allocated and released repeatedly while a call for providing high-speed data service is continued. Dogs may be assigned.

This section describes in detail the radio channel assignment procedure proposed by the EIA / TIA IS-95A or ANSI-STD-008 standard.

1 is a flowchart illustrating a radio channel allocation procedure of a mobile communication system according to the EIA / TIA IS-95A or ANSI-STD-008 standard.

Referring to FIG. 1, in the conventional radio channel allocation procedure, when a call is requested from a user side (UE), a base station (BTS) selects and assigns one CDMA channel among CDMA channels divided by frequency bands (S100); Allocating a frame offset for the assigned CDMA channel (S101), Allocating one traffic channel that is not being used among the allocated CDMA channels (S102), and Walsh code (Walsh) code) (S103), and the step (S104) of allocating the transmission power required for transmitting data to the radio section through the assigned call channel.

In the step S100, the allocation of the CDMA channel means the allocation of frequency resources. In the current system, one frequency resource is allocated among eight frequency resources of 1750 MHz to 1780 MHz in the uplink and 1840 MHz to 1870 MHz in the downlink.

Since the steps S101 to S104 after the CDMA channel assignment step S100 are radio assignment procedures of a general CDMA mobile communication system, description thereof is omitted.

FIG. 2A is a resource allocation diagram of available channels of the CDMA channel described with reference to FIG. 1, and FIG. 2B is a diagram illustrating radio channel resources managed for each CDMA channel managed by a conventional base station.

Referring to FIG. 2A, an available channel of a CDMA channel is divided into a normal call channel 200 that can be allocated to both a normal call and a handoff call, and a handoff call reservation channel 201 reserved for a handoff call only. .

Referring to FIG. 2B, in order to efficiently allocate and release each CDMA channel, the base station (BTS) may use the total number of available channels 202, the number of idle channels 203, the number of channels used 204, and the number of available channels 204 for each CDMA channel. The handoff call reservation channel number 205 and the handoff call allocation channel number 206 are managed separately.

Here, the total number of available channels 202 is the total number of channels held for each CDMA channel, the number of idle channels is the number of channels currently allocated from the total number of available channels 202, and the number of available channels 204 is the total number of available channels. This is the number of channels currently in use at 202. The number of handoff call reservation channels 205 is the number of channels reserved for the handoff call, and the number of handoff call assignment channels 206 indicates the number of channels currently allocated to the handoff call.

3 is a flowchart illustrating a detailed process of allocating a CDMA channel shown in FIG. 1.

Referring to FIG. 3, when a call is requested from a user side (UE), the base station (BTS) checks whether there is an idle channel that can be allocated in a CDMA channel currently being used, and if there is an idle channel, transfers one of the idle channels to the user side (UE). Assign (S300).

At this time, if the channel allocation for the requested call fails, the base station (BTS) selects the CDMA channel of the other frequency band with the largest number of idle channels and allocates one idle channel among the selected CDMA channels to the UE (S301, S303). If the channel allocation for the requested call fails again, the base station (BTS) does not allocate the radio channel for the requested call (S304, S305).

FIG. 4 is a flowchart illustrating a first embodiment of the process of allocating a CDMA channel shown in FIG. 3.

Referring to FIG. 4, the first embodiment describes a process of selecting and allocating an idle channel from a CDMA channel currently used by a base station (BTS) when a call is requested from a user side (UE).

First, the base station (BTS) checks whether there is an idle channel among the CDMA channels being used (S400).

If the idle channel does not exist according to the check result, the base station (BTS) fails to allocate the channel (S404). If the idle channel exists, the base station (BTS) checks whether the call requested from the user side (UE) is a normal call or a handoff call (S401). ).

Subsequently, if the call requested from the UE (UE) is a normal call according to the check result, the base station (BTS) compares the current handoff call allocation channel number with the handoff call reservation channel number (S402).

If the number of handoff call allocation channels is greater than or equal to the number of handoff call reservation channels, the base station BTS allocates one of the idle channels to the UE (S405 to S406).

However, if the number of handoff call allocation channels is less than the number of handoff call reservation channels, the base station (BTS) subtracts the number of handoff call allocation channels from the number of handoff call reservation channels and compares whether the result is greater than the number of idle channels. (S403).

As a result of the comparison, if the number of idle channels is large, the base station (BTS) allocates one of the idle channels except for the handoff call reservation channel to the UE (S405, S406). If the number of idle channels is small, the channel allocation fails (S404). ).

On the other hand, if the call requested from the user side (UE) in step S401 is a handoff call, the base station (BTS) reduces the number of idle channels by one and allocates one of the handoff call reservation channels to the user side (UE) (S407). S408).

FIG. 5 is a flowchart illustrating a second embodiment of the process of allocating a CDMA channel shown in FIG. 3.

Referring to FIG. 5, in a second embodiment, when a call is requested from a user side (UE), a base station (BTS) selects a CDMA channel having the most idle channels and selects and assigns an idle channel among the selected CDMA channels. Explain. This second embodiment applies when there is no idle channel among the CDMA channels currently used by the base station (BTS).

First, the base station (BTS) checks whether the call requested from the user side (UE) is a normal call or a handoff call (S500).

If the call requested from the UE (UE) is a normal call according to the result of the check, the base station (BTS) selects the CDMA channel having the largest idle channel among the CDMA channels of all the frequency bands in use (S501), and selects any of the selected CDMA channels. Select an idle channel and assign it to the user side (UE). If the selection of the CDMA channel with the most idle channels fails (S502), the base station (BTS) fails to allocate the CDMA channel (S505).

On the other hand, if the call requested from the user side (UE) in the step (S500) is a handoff call, the base station (BTS), like the normal call, selects the CDMA channel with the most idle channels among the CDMA channels of all frequency bands in use ( S506), an arbitrary idle channel is selected from the selected CDMA channel and assigned to the user side (UE).

However, if selection of the CDMA channel with the most idle channels fails (S507), the base station (BTS) selects another CDMA channel (S508), and allocates an idle channel among the selected CDMA channels to the user (S511). At this time, the number of idle channels decreases and the number of handoff allocated channels increases. If the selection of the CDMA channel having the most idle channels fails again, the base station (BTS) fails to allocate the CDMA channel (S505).

However, in consideration of the conventional radio channel allocation procedure applied in the IS-95A standard, the base station (BTS) is assigned to only one base channel (FCH) for a single call requested from the user side (UE) by high speed The following problem occurs when additionally assigning at least one additional channel (SCH) in addition to the basic channel (FCH) for the data service.

First, since the conventional CDMA channel allocation process and the frame offset allocation process operate on the basis of allocating one radio channel, if N additional channels (SCH) are required, the same channel allocation process is repeatedly performed N times. There is a problem that results in a time delay.

Second, since the radio channel that the base station (BTS) can provide to the user side (UE) is limited, when allocating the required additional channel (SCH) without restriction, system channel resources are insufficient to accommodate other voice calls. There is a problem.

In more detail, in the case of a voice call, in general, the voice call can be used at a variable rate of 1, 1/2, 1/4, 1/8, etc. according to the user's voice activity. As a result, the increase in additional channels is a major cause of the decrease in system channel capacity. Therefore, considering the service utilization rate of users, the voice call is required more statistically than the data call, but as the allocation of additional channel with fixed transmission rate increases, it is impossible to service other voice calls normally due to the lack of system channel resources. Problem occurs.

Third, if a handoff of an additional channel (SCH) allocated for high-speed data service is required in a situation where there is no channel resource for a normal call by allocating all required normal calls, a handoff call reservation channel is inevitably created. The allocation reduces the number of handoff call reservation channels. In this situation, when a handoff is required for an allocated voice call, the base station (BTS) cannot allocate a handoff call reservation channel for the voice call, thereby causing a problem that the quality of the voice call is degraded or dropped. .

Accordingly, an object of the present invention has been made in view of the above-mentioned problems of the prior art, and a high speed data service capable of efficiently allocating an additional channel (SCH) for a high speed data service according to a system channel resource allocation situation. It is to provide a method.

In the high-speed data service method according to an aspect of the present invention for achieving the above object, when an additional channel for data service is required from a user side (UE), a base station (BTS) is assigned to the requested additional channel in a given CDMA channel. Calculating the number of allocable idle channels; comparing the calculated number of idle channels with a preset number of additional channel allocation restriction channels; and the additional channels with the calculated number of idle channels already set according to the comparison result. If the base station (BTS) is larger than the allocation limit channel number, the base station (BTS) allocates the requested additional channel, or if the calculated idle channel number is less than the required additional channel number according to the comparison result, the base station controller (BSC) of Under the control, the base station (BTS) determines whether to allocate the requested additional channel.

Preferably, the step of calculating the number of idle channels is a first step of calculating a difference value by subtracting the additional channel allocation limit channel number already set from the total number of available channels for the given CDMA channel, and using among the given CDMA channels. And a second step of subtracting the difference value calculated in the first step from the pure idle channel.

1 is a flowchart illustrating a radio channel assignment procedure of a mobile communication system according to the EIA / TIA IS-95A or ANSI-STD-008 standard.

FIG. 2A is a resource allocation diagram for an available channel of the CDMA channel described in FIG.

2B is a diagram illustrating radio channel resources managed for each CDMA channel managed by a conventional base station.

3 is a flow chart showing in detail the allocation process of the CDMA channel shown in FIG.

FIG. 4 is a flowchart showing a first embodiment of the process of allocating a CDMA channel shown in FIG.

FIG. 5 is a flowchart showing a second embodiment of the process of allocating a CDMA channel shown in FIG.

6 is a resource allocation diagram for an available channel of a CDMA channel according to the present invention.

7 is a diagram illustrating radio channel resources managed by a base station for each CDMA channel according to the present invention.

8 is a diagram showing a first embodiment of an additional channel allocation method according to the present invention;

9 illustrates a second embodiment of an additional channel allocation method according to the present invention.

* Description of the symbols for the main parts of the drawings *

700: total number of available channels 701: number of idle channels

702: number of channels used 703: number of handoff call reservation channels

704: number of handoff call allocation channels 705: number of voice call priority allocation channels

Hereinafter, a configuration and an operation according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings.

The present invention proposes a high speed data service method for efficiently allocating an additional channel (SCH) for a high speed data service according to a system channel resource allocation situation.

To this end, a base station (BTS) according to the present invention sets a channel that can be allocated only to a call for other services except for a high-speed data service, and sets it as an additional channel limit threshold to add an additional channel according to a system channel allocation situation. Limit the allocation of channels.

6 is a resource allocation diagram for an available channel of a CDMA channel according to the present invention.

Referring to FIG. 6, each CDMA channel according to the present invention may be allocated to all channels regardless of the type of service requested by the user side (UE), and for other services except for the high-speed data service. The second channel 601 is allocated to the call and the third channel 602 reserved for the handoff call.

Here, the first channel 600 is a channel that can be allocated to all data calls, general voice calls, and handoff calls for high-speed data services, and the second channel 601 is an additional channel (SCH) for high-speed data services. Except for the normal call of other services, the channel can be assigned preferentially, and the third channel 602 is a channel that can be allocated when the UE requests a handoff call.

The reason for distinguishing the first channel 600 from the second channel 601 is to limit the allocation of the additional channel (SCH) that uses more system capacity than the voice call according to the system channel resource situation.

That is, in the additional channel allocation method according to the present invention, the additional channel (SCH) for the high speed data service is allocated only when the number of currently allocated and used channels is smaller than the number of the first channels 600. Therefore, if the currently allocated channel being used exceeds the number of the first channel 600, the additional channel SCH is not allocated.

As a result, the number of first channels 600 or the number of second channels 601 is regarded as an additional channel allocation limit threshold that limits the allocation of additional channels.

7 illustrates radio channel resources managed by a base station for each CDMA channel according to the present invention.

Referring to FIG. 7, the CDMA channel managed by the base station (BTS) according to the present invention includes the total number of available channels 700, the number of idle channels 701, the number of used channels 702, and the handoff call reservation channel. The number 703, the handoff call allocation channel number 704, and the additional channel allocation restriction channel number 705 are divided.

Here, the total number of available channels 700 is all channels available in the CDMA channel, the number of idle channels 701 is a channel that is currently available, the number of used channels 702 is the channel currently being used, and handoff call reservation Channel number 703 means a channel reserved for a handoff call, and handoff call assignment channel number 704 means a channel currently assigned to a handoff call. The additional channel allocation limit channel number 705 denotes a channel that can be preferentially allocated to other services, particularly voice calls, except for data calls for high-speed data services.

The additional channel allocation restriction channel is a channel added according to the present invention, and the base station (BTS) allocates the additional channel (SCH) requested by the UE (UE) up to the number of additional channel allocation restriction channels 705 among all available channels. This means that the additional channel (SCH) that can be allocated by the base station (BTS) is limited.

8 is a diagram showing a first embodiment of an additional channel allocation method according to the present invention, and FIG. 9 is a diagram showing a second embodiment of the additional channel allocation method according to the present invention.

Referring to FIG. 8, a radio channel for high speed data service is divided into a basic channel (FCH) and an additional channel (SCH). Here, the basic channel (FCH) is a channel allocated by default when initial call setup when a user requests high-speed data service, and the additional channel (SCH) adjusts the data rate required after the allocation of the basic channel (FCH). Is an additional channel. Accordingly, a process of allocating a basic channel (FCH) and an additional channel (SCH) is required for a high speed data service.

The process of allocating a basic channel (FCH) for a high speed data service is the same as in the prior art, and the process of allocating an additional channel (SCH) is according to the present invention.

The additional channel allocation method according to the present invention is as follows.

First, it is assumed that the UE (UE) has requested a high speed data service and the base station (BTS) has already allocated a basic channel (FCH) for the requested high speed data service.

In this state, when an additional additional channel (SCH) is required for the allocated base channel (FCH), the base station (BTS) first allocates the additional channel (SCH) in the corresponding CDMA channel to which the base channel (FCH) is assigned. It is checked whether an idle channel can exist (S800).

At this time, the base station (BTS) calculates whether there is an idle channel to which the additional channel (SCH) can be allocated as in the following equation.

Idle Channels = Pure Idle Channels-(Total Available Channels-Additional Channel Allocation Limit Channels)

In Equation 1, the pure idle channel number is the number of idle channels available in the CDMA channel to which the basic channel (FCH) is currently allocated, and the additional channel allocation restriction channel number is the number of channels to which no additional channel can be allocated as described above. Therefore, the result value of Equation 1 indicates whether the CDMA channel currently in use exceeds the number of additional channel allocation limit channels.

That is, when the result value of Equation 1 is greater than '0', it means that as many additional channels (SCH) as the result value can be allocated. On the other hand, when the result value of less than or equal to '0', additional channel (SCH) is assigned. It means that no channel resource can be allocated.

Therefore, the base station (BTS) checks the result value of Equation 1 and determines whether the calculated number of idle channels is greater than '0' (S801).

When the number of idle channels calculated according to the determination result is less than or equal to '0', the base station BTS determines that the additional channel SCH cannot be allocated and fails to allocate the additional channel (S807). However, when the calculated idle channel number is greater than '0' according to the determination result, it is checked whether the calculated idle channel number is larger than the additional channel number requested by the user (S802).

When the number of idle channels calculated according to the check result is larger than the required number of additional channels, the base station BTS allocates all of the requested additional channels (S806). However, if the calculated number of idle channels is less than the required number of additional channels, the base station receives the control signal from the base station controller BSC (S803) and uses the two additional channels (SCH) in two ways according to the received control signals. Assign.

The first is a method of allocating the calculated idle channels to the additional channel (S804), and the second is a method of not allocating the additional channel (SCH) as shown in FIG. 9 (S904). At this time, the base station controller (BSC) determines whether to allocate the additional channel according to the channel allocation situation and the hand-off processing situation of the neighboring base station. That is, the base station controller (BSC) to the candidate base stations determined that the additional channel can be allocated In addition to requesting the allocation of additional channels, the base station determines the additional channel allocation status of the candidate base stations in two ways. One of them is a method of allocating the required additional channels by reflecting the number of additional channels allocated by the base station, and the other is a method of not allocating the required additional channels. After the base station controller (BSC) makes the above determination, the base station controller (BSC) delivers the determined processing method together with the requested number of additional channels to the candidate base stations. The base station processes according to this standard. The base station controller (BSC), when there are a plurality of candidate base stations, makes an additional channel allocation request to each candidate base station, compares the number of additional channels allocated by each base station, and finally allocates the largest number of additional channels to the base station. To approve the assignment. The remaining candidate base stations make a release request for the allocated additional channel. In summary, the amount of additional channels allocated to the required number of additional channels is insufficient (if the calculated number of idle channels is less than the required number of additional channels, the difference between the calculated number of idle channels and the required number of additional channels). A base station controller (BSC) applies a control signal of allocation acceptance or cancellation of an additional channel to the base station.

After allocating the additional channel (SCH) according to the above process, the base station (BTS) decreases the number of idle channels by the allocated number of additional channels (S805).

Meanwhile, the method of allocating the additional channel described above is equally applied to both the normal call and the hand hop call in order to use the hand hop call reservation channel efficiently. Therefore, if the allocation of the additional channel is requested by the handoff call, after the additional channel is allocated, the number of handoff allocation channels is also updated along with the update of the effective channel number.

As described above, the high speed data service method according to the present invention has the following effects.

First, the allocation of additional channels for high-speed data service is partially restricted according to the system channel situation, so that the additional system channel resources can be allocated to voice calls with more demand than high-speed data service, thereby providing a communication service of a certain quality. have.

Second, since the additional channel allocation method according to the present invention can be applied to the normal call and the handoff call in the same way, the system can be easily applied and the voice call capable of handling the handoff can be increased.

Third, the system can be easily constructed by maintaining the compatibility with the conventional call allocation method for the non-high speed data service by processing the basic channel allocation process and the additional channel allocation process for the high speed data service.

Fourth, the channel allocation time can be shortened by allocating multiple additional channels for high-speed data service simultaneously.

Claims (5)

Calculating, by the base station (BTS), the number of idle channels that can be allocated to the requested additional channel in a given CDMA channel when an additional channel for data service is required from the user side (UE); Comparing the size of the calculated idle channels with the number of additional channel allocation restriction channels already set; If the calculated idle channel number is greater than the additional channel allocation limit channel number already set according to the comparison result, the base station (BTS) allocates the requested additional channel, or When the calculated number of idle channels is smaller than the required number of additional channels according to the comparison result, the base station BTS determines whether to allocate the requested additional channels under control of a base station controller BSC. High speed data service method, characterized in that. The method of claim 1, wherein the calculating of the number of idle channels comprises: A first step of calculating a difference value by subtracting the additional channel allocation limit channel number already set from the total number of available channels for the given CDMA channel; And a second step of subtracting the difference value calculated in the first step from a pure idle channel not in use in the given CDMA channel. The method of claim 1, wherein the allocation of the additional channel, Comparing the calculated size of the idle channel and the requested number of additional channels with each other; And if the calculated number of idle channels is larger than the requested number of additional channels according to the comparison result, the base station (BTS) allocating all of the requested additional channels. The method of claim 1, wherein the base station controller (BSC), if the calculated number of idle channels is less than the requested number of additional channels, the calculated number of idle channels and the required number of additional channels compared to the requested number of additional channels And controlling the base station to determine whether to allocate the requested additional channel with respect to the size difference between the base stations. 2. The method of claim 1, wherein the base station (BTS) is different from the first channel, except for the requested data service, to allocate the given CDMA channel to all calls regardless of the type of service requested from the user side (UE). And managing a second channel allocated to a call for service and a third channel reserved for a handoff call.