KR100324127B1 - Method for assigning frequency in a mobile communication system - Google Patents

Abstract

The present invention relates to a frequency allocation method in a mobile communication system that allows a user to receive a high quality call service by allocating call resources at low load using substantial frequency allocation data. If requested, the type of call is searched. If the type of the search is not a basic call, B-Link resource / frame offset / frequency channel / walsh code is allocated, traffic gain (TC) is allocated, and the corresponding subcell is assigned. After updating the power bank, the number of calls allocated to the subcells is increased, a traffic channel is allocated, and when the type of the searched call is a basic call, a B-Link resource / frame offset is allocated and received. Check whether the number of calls allocated to the subcell of the originating / incoming call is larger than the call-block-threshold of the corresponding subcell. If the number of calls allocated to the vessel is smaller than the call-block-threshold, a frequency channel is allocated. In addition, if the number of calls allocated to the subcell is larger than the call-block-threshold, the frequency is allocated by distributing the load to other FAs owned by the base station for voice quality.

Description

Method for assigning frequency in a mobile communication system

The present invention relates to frequency allocation (FA) in CDMA mobile communication systems (PCS, DCS), and in particular, the user can allocate high-quality call resources to frequencies with less load by using actual frequency allocation data. The present invention relates to a frequency allocation method in a mobile communication system.

1 is a diagram illustrating a configuration of a general CDMA mobile communication system.

Mobile station 10 (MS) communicates data wirelessly with base station 20 (BTS), and base station 20 interfaces data wirelessly with mobile station 10 under control of control station 30 (BSC). do.

In the figure, reference numeral 40 denotes a control station manager (BSM), and reference numeral 50 denotes a mobile communication switch (MSC).

In the CDMA mobile communication system configured as described above, in a multi-FA base station having two or more frequency channel resources, a base station control processor (BCP) is a base station resource (blink, frequency channel, frame offset, Walsh code) when an incoming / outgoing signal is received. , Power, traffic channels, etc.).

In the conventional method for frequency allocation during such resource allocation, the mobile station determines the frequency channel information transmitted from the base station and the hash function result value of its own terminal number as the service frequency channel. To be randomly distributed.

The appointment between the base station and the mobile station is defined by the standard, and works well in a situation where the traffic allocation of the base station is distributed evenly over all frequency channels.

However, in a situation where traffic channels are concentrated at a specific frequency, traffic channels may be reassigned to a frequency channel that is heavily loaded due to a random frequency channel distribution method, which affects mutual interference between mobile stations, resulting in poor service quality. Can be dropped.

Therefore, at the time of newly assigning traffic channels, measures for distributing frequency channel allocations are required by allocating a frequency with less load based on actual frequency channel resource information.

Accordingly, the present invention has been proposed to solve various problems occurring in the conventional random frequency channel distribution scheme as described above.

An object of the present invention is to provide a frequency allocation method in a mobile communication system that allows a user to receive a high quality call service by allocating call resources with a low load frequency using substantial frequency allocation data.

The present invention for achieving the above object,

When a call attempt is made to a specific frequency channel of the mobile station, it is determined that the frequency channel distribution is not evenly distributed when compared to the preset Call Block Threshold, and the number of calls allocated to all FAs is searched. Allocate frequency channel resources to the FAs with the least load afterwards.

1 is a block diagram of a general CDMA mobile communication system,

2 is a flowchart illustrating a frequency allocation method in a mobile communication system according to the present invention.

<Explanation of symbols for the main parts of the drawings>

10: mobile station (MS)

20: base station (BTS)

30: control station (BSC)

40: control station management unit (BSM)

50: mobile communication switch (MSC)

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention according to the technical spirit as described above in detail.

To increase call capacity and provide good call quality, CDMA systems use forward and reverse power control. Through the transmission power control for all mobile stations, the system capacity can be maximized if the mobile station originating signal is received at the base station with a minimum required signal-to-interference ratio. If the signal from the mobile station is received too weak, the operating performance of the mobile station will be degraded. If the signal from the mobile station is strongly received, the mobile station's operating performance will be improved, but the interference with other mobile stations on the same channel will be increased, so as not to reduce the maximum capacity. The call quality of the subscriber is lowered below the level.

Therefore, the present invention determines the call block threshold in advance in order to guarantee a certain level of call quality in a base station that is a multi-FA using a frequency load distribution algorithm using a call block threshold, and if it is above this threshold, the RTD value is retrieved by searching for the RTD value. If the value is above the RTD threshold in the PLD, it is considered as the neighboring area of the base station, and if it is below the value of the RTD, it searches for the number of calls assigned to the unique FA and allocates the frequency channel resources to the least allocated FA to distribute the load Let's do it.

The call block threshold is currently defined as 14 (KTF requirement), and the value in the IS95B PLD (normal_call_blk_thr of st_subcell_data) will be used in the future.

Hereinafter, a preferred embodiment of the present invention will be described.

2 is a flowchart illustrating a frequency allocation method in a mobile communication system according to the present invention.

First, when the resource allocation request comes in step S1, the type of call is retrieved. Types of calls used in CDMA systems include outgoing / incoming calls, soft handoff calls, soft handoff calls, hard handoff calls, RF test calls, Markov calls, and loopback calls. , BRAX) should allocate resources that fit the characteristics of the call type.

In step S2, it is checked whether the type of the retrieved call is a basic call (outgoing / incoming call), and in the case of the basic call, in step S3, a B-Link resource for transmitting voice data with the control station BSC is allocated.

The frame offset is allocated in step S4, and it is checked whether the number of calls allocated to the subcells of the outgoing / incoming signal received in step S5 is larger than the call-block-threshold value of the corresponding subcell.

As a result of this check, if the number of calls allocated to the subcell is smaller than the call block threshold, resources are allocated to the FA received in step S8.

The Walsh code is allocated in step S9, the traffic gain TC is allocated in step S10, the power bank of the corresponding subcell is updated, and the number of calls allocated to the subcell is increased by '1'. In addition, the traffic channel is allocated in step S11.

On the other hand, if it is determined that the call type is not a basic call, in step S6, a B-Link resource for transmitting voice data is allocated to a control station (BSC), and a frame offset is allocated in step S7.

As is well known, the resource is allocated to the FA received in step S8.

In addition, the Walsh code is allocated in step S9, the traffic gain TC is allocated in step S10, the power bank of the corresponding subcell is updated, and the number of calls allocated to the subcell is increased by '1'. In addition, the traffic channel is allocated in step S11.

On the other hand, as a result of comparing the call number assigned to the subcell with the call-block-threshold, if the number of call allocated to the subcell is larger than the call-block-threshold, the other base station has a different FA for voice quality. Distribute the load.

That is, the resource is searched in consideration of the frequency characteristics of the FA by using the RTD value of the received call to generate less hard handoff in step S12. The RTD is a value for estimating the distance between the mobile station and the base station. Therefore, the RTD value of the received call is compared with the RTD threshold of the sector in the PLD. If the RTD value of the received call is larger than the RTD threshold, the common FA is searched in step S13, considering that it is in the handoff area.

Here, the common FA is a frequency commonly used with neighboring base stations, and soft handoff occurs when handoff occurs to another base station.

In step S14, it is checked whether there are fewer FAs allocated to the subcells than the call-block-threshold value. If there are any FAs, the process proceeds to step S8, which allocates frequency channels, and repeats the following steps.

On the other hand, if there are no FAs less than the call-block-threshold value assigned to the subcell, the unique FA is searched for in step S15. If it is determined in step S16 that the number of calls allocated to the subcell with the unique FA is less than the call-block-threshold value, the process moves to step S8 and assigns a frequency channel, and repeats the following steps. . On the contrary, if there are no FAs allocated to the subcell with the unique FA less than the call-block-threshold, the call setup is considered to be absent in step S17 and the call setup is stopped.

The unique FA is a frequency used only for a specific base station, and hard handoff occurs when a handoff occurs.

On the other hand, as a result of comparing the RTD of the received basic call with the RTD threshold, if the RTD of the received basic call is smaller than the RTD threshold, the unique FA is searched in step S18. If it is determined in step S19 that there are fewer FAs allocated to the subcell with the unique FA than the call-block-threshold, the process moves to step S8 and assigns a frequency channel, and repeats the following steps. . On the other hand, if there are no FAs allocated to the subcell with the unique FA less than the call block threshold, the common FA is searched for in step S20.

In step S21, it is determined whether the number of calls allocated to the subcell to which the common FA belongs is less than the call-block-threshold value. If so, the process moves to step S8, and allocates a frequency channel, and repeats the following steps. .

On the contrary, if there is no FA less than the call-block-threshold value assigned to the subcell, call setup is considered to be absent in step S17 and the call setup is stopped.

According to the present invention, the frequency allocation method in the mobile communication system as described above, by assigning a frequency channel using the actual frequency allocation data, it is possible to efficiently select a frequency channel in terms of signal to noise ratio between mobile stations within the same frequency. There is an advantage that can be dispersed.

Claims (3)

In the frequency allocation method of the mobile communication system, A first step of retrieving the type of call if resource allocation is requested; If the type of the searched call is not a basic call, a B-Link resource / frame offset / frequency channel / walsh code is allocated, a traffic gain (TC) is allocated, the power bank of the corresponding subcell is updated, and the subcell is Increasing the number of calls assigned to the network and allocating a traffic channel; If the searched call is a basic call, allocate a B-Link resource / frame offset, and is the number of calls allocated to a subcell of a received outgoing / incoming signal greater than the call-block-threshold of the corresponding subcell? Checking the third step; A fourth step of allocating a frequency channel when the number of calls allocated to the subcell is less than the call block threshold as a result of the checking; A fifth step of distributing the load by distributing the load to other FAs owned by the base station for voice quality when the number of calls allocated to the subcell is greater than the call block threshold as a result of the checking of the third step; Frequency allocation method in a mobile communication system, characterized in that made by. 2. The method of claim 1, wherein the fifth step comprises: comparing the RTD value of the received call with the RTD threshold of the sector in the PLD; and if the RTD value of the received call is greater than the RTD threshold, then the step is in the handoff region. Retrieving a common FA, considering whether there are FAs less than the call-block-threshold value, and assigning the aforementioned frequency channel, if the number of calls allocated to the subcells is call- If there are no FAs less than the block-threshold, searching for a unique FA and assigning a frequency channel if the number of calls allocated to the subcell with the unique FA is less than the call-block-threshold is determined. If the number of calls allocated to the subcell with the unique FA is less than the call-block-threshold, the call setup is assumed to be absent and the call setup is stopped. A frequency allocation method in a mobile communication system in which the burden is characterized. The method of claim 1 or 2, wherein the fifth step further comprises: searching for a unique FA if the RTD of the received basic call is smaller than the RTD threshold as a result of comparing the RTD of the received basic call with the RTD threshold. And if the number of calls allocated to the subcell with the unique FA is less than the call-block-threshold, the frequency channel is allocated, and the number of calls allocated to the subcell with the unique FA is the call- Searching for a common FA if there are no FAs less than the block-threshold, and checking if there are fewer FAs assigned to the subcell to which the common FA belongs, if there are fewer FAs than the call-block-threshold, And if there is no FA less than the call-block-threshold, the call setup is assumed to be absent and the call setup is stopped. A frequency allocation method in a mobile communication system.