KR100860024B1 - Method for operating searcher in communication system - Google Patents

Abstract

The present invention relates to a searcher operating method, and more particularly, to a searcher operating method capable of supporting a plurality of channels with a plurality of searchers in an IS-95 base station system. Such a searcher operation method sets the number of channels of the highest priority channel search queue to the number of remaining channels, and if any searcher index is smaller than the full searcher index, whether the searcher has performed a full search for the channel to be searched. Determining and searching for all of the highest priority channels, and if the searcher has searched for all of the highest priority channels, then the searcher provides the next priority until the channel being searched for the next priority channel search queue is null. Performing a channel search, and when the search for the next priority channel is completed, the searcher performs a channel search until the channel search for the next priority channel search queue becomes null.

Explorer operation

Description

Method for operating searcher in communication system

1 is a block diagram of a searcher and a searcher peripheral block of a base station system for explaining a searcher operating method according to the present invention;

2A and 2B are flowcharts for explaining a search resource management subroutine in the searcher operating method according to the present invention.

3A and 3 are flowcharts illustrating a search completed subroutine in the searcher operating method according to the present invention.

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

10: interrupt control 20: system timer

30: searcher 40: central processing unit

The present invention relates to a searcher operating method, and more particularly, to a searcher operating method capable of supporting a plurality of channels with a plurality of searchers in an IS-95 base station system.                         

In general, a code-division multiple access (CDMA) wireless communication system includes a mobile station (MS) and a base station. The mobile communication signal modulated and transmitted from the mobile station is received by the base station, demodulated by the base station, and restored to the original signal. In this case, the mobile communication signal includes a pilot signal for time synchronization and power control. The pilot signal is a signal transmitted to the base station by spreading with a unique PN code for each terminal user. The base station can demodulate the received signal by finding the respective time delays, ie, PN offsets, of the multipath components of the pilot signal to search for the pilot signal. In order to find the PN offset, all the offsets of the received signal may be despread using the PN signal, the energy of the despread signal is calculated, an average value is calculated, and a specific threshold value among the plurality of energy values is obtained. Select the PN offset of the multipath signal with greater energy value. The device that performs this operation is called a "searcher."

In general, each dependent searcher exists for M channels.

If the data rate is the lowest (1200 or 1800 bps) due to the characteristics of the DBR (Data Burst Randomizer) of the reverse link of the IS-95-A / B, only two 1.25ms sections exist for 20ms and the other sections May not exist. However, the conventional technology is a structure in which each dependent searcher exists unconditionally for M channels, and since the searcher cannot be shared with other channels, unnecessary operation is performed even in a section where data of the corresponding channel is not present by the DBR. There was a problem with inefficient search operations.

The present invention has been made to solve the above-mentioned problems of the prior art, to provide a searcher operating method in a communication system that can support a plurality of channels than the number of searchers to a plurality of searchers in the IS-95 base station system. It is for.

In the present invention, the searcher operating method sets the number of channels of the highest priority channel search queue to the number of remaining channels, and if any searcher index is smaller than the total searcher index, the searcher searches for a channel to be searched by the searcher. determining whether a search has been performed and searching all of the highest priority channels, and if the searcher has searched all of the highest priority channels, the searcher until the channel being searched for the next priority channel search queue is null. Performing the next priority channel search, and if the search for the next priority channel is completed, the searcher performs a channel search until the channel search for the next priority channel search queue becomes null. Is made of.

Advantageously, said highest priority channel discovery queue is a queue assigned to an access preamble discovery mode, said second priority channel discovery queue is a queue assigned to a traffic preamble discovery mode, and said third priority channel discovery queue is a traffic multipath. Queue assigned to seek mode.                         

And if the search is not completed for the channel to be searched, the search command for the next sector or the next window of the search item is increased, and the index of the searcher is increased.

Hereinafter, a searcher operating method according to the present invention will be described with reference to the accompanying drawings.

1 is a block diagram of a searcher and a searcher peripheral block of a base station system for explaining a searcher operating method according to the present invention.

The present invention relates to a searcher operating method for supporting M channels with N searchers in a communication system, in particular an IS-95-A / B base station system. The environment for this purpose is to generate an interrupt in the system timer 20 and a central processing unit 40, which is a processor, which is arranged in a system reference time to inform current time information, and the central processing unit 40. Despread by using the PN signal all offsets that the received signal received by the base station under the control of the interrupt control unit 10 and the central processing unit 40 to control the interrupt so that the interrupt is cleared by And a searcher for calculating a mean value by calculating the energy of the despread signal, and then selecting a PN offset of the multipath signal having an energy value greater than a specific threshold value among the plurality of energy values. It consists of two search parts 30a, 30b ... 30n: 30.

In this case, two interrupts are used in the present invention, that is, a time tick interrupt and an offset time tick interrupt.

Here, the time tick interrupt is generated every 1.25 ms aligned to the system reference time, and performs a search resource management subroutine according to the time tick interrupt.

The offset time tick interrupt is generated every 1.25 ms with a constant offset from the system reference time. The offset time tick interrupt performs a search done subroutine according to the offset type tick interrupt.

Although not shown, each search unit 30 has a search parameter buffer and a search result buffer, and a search start command is a reference time of the search unit 30. run at the 1.25 ms boundary of the reference time). Here, the search unit 30 reference time is separated from the system reference time by the processing delay time of the search unit.

When an i-th searcher occupies a time slot to perform an offset-wise hyperthesis test for one search command, N searchers 30 and each search section 30, a rake width allocated by: between (rake width R _X), holds the R ₁ + R ₂ + ‥‥ relationship R _N ≤R.

That is, within the total rake width (R), the number of search units 30 and the rake width of each search unit 30a, 30b ... 30n: 30 may dynamically change to occupy time slots. In the present invention, a fixed number of search units 30 and a method of operating the search unit 30 by fixing the rake width of each search unit 30 are used.

The data burst randomizer (DBR) is a technology applied to RC1 and RC2, which are reverse link radio configurations of IS-95-A / B.

When a 20ms frame is divided into 16 1.25ms power control groups (PCGs), and each of PCG0, PCG1, ..., and PCG15, each PCG is turned on and off according to a data burst randomizer (DBR) pattern. Each PCG has 1,536 long codes, among which the last 14 long code values of PCG14 determine the DBR pattern of the next 20ms frame.

The long code is determined by a long code state common to all channels and a long code mask having a unique value for each channel.

In addition, a frame boundary is determined by a frame offset assigned to each channel.

When the 14 long codes described above are designated as b0, b1, ..., b13 in the order of occurrence, the PCG (PCG0, PCG1, ..., PCG15) turned on by the DBR pattern according to the data rate is as follows. Is determined as follows. In this case, PCG is omitted for convenience.

When the data rate is 9,600 or 14,400 bps,

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15.

When the data rate is 4,800 or 7,200 bps

b0, 2 + b1, 4 + b2, 6 + b3, 8 + b4, 10 + b5, 12 + b6, 14 + b7.                     

When the data rate is 2,400 or 3,600 bps

b0 if b8 = 0, or 2 + b1 if b8 = 1;

4 + b2 if b9 = 0, or 6 + b3 if b9 = 1;

8 + b4 if b10 = 0, or 10 + b5 if b10 = 1;

12 + b6 if b11 = 0, or 14 + b7 if b11 = 1.

When the data rate is 1,200 or 1,800 bps

b0 if (b8, b12) = (0,0), or

2 + b1 if (b8, b12) = (1,0), or

4 + b2 if (b9, b12) = (0,1), or

6 + b3 if (b9, b12) = (1,1);

8 + b4 if (b10, b13) = (0,0), or

10 + b5 if (b10, b13) = (1,0), or

12 + b6 if (b11, b13) = (0,1), or

14 + b7 if (b11, b13) = (1,1).

Here, PCGx, which is on when the data rate is low, is always on when the data rate is higher than that.

There are three search modes for the channels of the IS-95-A / B.

That is, access preamble search mode (hereinafter abbreviated as ACH), traffic preamble search mode (hereinafter referred to as PAM), and traffic multipath search mode (hereinafter referred to as PAM). MUL abbreviation).

An access preamble search (ACH) is a search mode having the highest priority and needs to search for an access preamble section for each access slot. DBR is not applied in ACH mode.

Traffic preamble search (PAM) is a mode having a medium priority, and no DBR is applied.

Traffic multipath search (MUL) is a mode with the lowest priority and DBR is applied.

In the present invention, the method of operating a search unit (hereinafter referred to as a searcher) assigns searchers in order of higher priority by giving priority to each channel to be searched, and if the priority is the same, the search order is the oldest channel order. Is to allocate an explorer.

In order to enable priority search, each search mode has an independent search queue and assigns it to the searcher from the items in the high priority queue. The search item operates the search queue in such a manner that the search order is determined by the order in which the queue is contained.

In the case of MUL (traffic multipath search) search, the search performance is improved by assigning the searcher only to the PCG section that is always on based on the DBR information of each channel.

Items common to all channels in the search information list required for each M channel are as follows.

ChannelType: Shows whether it is an access channel or a traffic channel.

Search Mode (SrchMode): Indicates whether it is ACH, PAM or MUL.

NumSrchSector: The number of sectors on which the search should be performed.

Search Sector List (SrchSectorList): Search sector list (search source (SearchSource (SearchSectorIdx and antenna)), search start offset, search window size (SearchStartOffset, SearchWindowSize)) as many as the number of sectors to be searched Let me know.

Current Sector Sector Index (CurrSrchSectorIdx): Indicates which sector of the sectors to search in SrchSectorList. index

Current Search Window (CurrSrchWin): Tells you how many partial searches you are searching for as long as the search rake for a single search to search by SearchWindowSize.

The following is a list of discovery information required for an access channel.

Access preamble size: AccessPamSize.

Access slot size: AccessSlotSize.

Access Frame Index (AccessFrameIdx): Indicates the number of frames within the access slot of the current frame.

Access Channel Last Seek Complete Time (AchLastSrchDoneTime). Indicates the last time the access channel was whole browsed.

The following is a list of search information needed for the traffic channel.

Frame Offset: Indicate the frame offset of the channel.

First PCG: First PCG tells you the index of the first PCG that is on when the data rate is 1,200 or 1,800 bps.

Second PCG (SecondPCG): Based on DBR information, it informs the index of the second PCG that is on when the data rate is 1,200 or 1,800 bps.

The searcher operation method proposed in the present invention can be largely divided into seven subroutines.

The first is a subroutine in channel setup.

The second is the search subroutine on channel release.

The third is the search subroutine when changing the search mode of the channel.

The fourth is a subroutine when setting softer handoff mode.

Fifth is the subroutine on softer handoff mode release.

Sixth is the resource management subroutine.

Finally, the seventh is a done subroutine.

First, the search subroutine when setting an arbitrary i-th channel is as follows.                     

First of all, in the first step,

Whether an access channel or a traffic channel is specified is specified in a channel type (ChannelType) of the search information list of the i-th channel.

The discovery mode (SrchMode) is set to ACH when setting an access channel and PAM when setting a traffic channel.

In the case of traffic channels, the frame offset is set to a value assigned to each channel.

In the case of an access channel, an access preamble size (AccessPamSize) and an access slot size (AccessSlotSize) designated for each channel are set, and an access channel last search completion time (AchLastSrchDoneTime) is initialized to zero.

To the next step,

Search parameters such as the search source (start start offset) and search window size (window size) corresponding to the i-th channel are displayed in the first search sector list (SrchSectorList). ) And the number of search sectors (NumSearchSector) is set to one.

Then in the third step,

The i th channel is registered as a search item in the search queue according to the search mode SrchMode.

The search subroutine on the second arbitrary i-th channel release is as follows.

First of all,                     

The i-th channel search item is removed from the search queue according to the search mode (SrchMode) of the i-th channel.

To the next step,

The search sector list SrchSectorList of the i-th channel is flushed, and the number of search sectors NumSrchSector is zero.

When changing the search mode of the third arbitrary i-th channel, the subroutine is as follows.

In the case of the traffic channel, when switching to the multipath search mode after preamble acquisition, the search mode (SrchMode) is set to MUL in the search information list of the i-th channel.

When setting the softer handoff mode of the fourth arbitrary i-th channel, the subroutine is as follows.

Search Source, Search Window Size, and Search Start Offset information is searched for the sectors added from the search information list of the i-th channel. NumSrchSector The Sector Sector List (SrchSectorList). Is added to, and the search sector number NumSrchSector is increased by one.

The subroutine upon release of softer handoff mode of the fifth arbitrary i-th channel is as follows.

The number of search sectors NumSrchSector is reduced by one from the search information list of any i-th channel. The search source (SearchSource), the search start offset (SearchStartOffset), and the search window size (SearchWindowSize) related to the sector to be removed are completed by removing from the search sector list SrchSectorList.

Sixth, the discovery resource management subroutine will be described with reference to FIGS. 2A and 2B. Seventh, the discovery completion subroutine will be described with reference to FIGS. 3A and 3B.

2A and 2B are flowcharts illustrating a search resource management subroutine in the searcher operating method according to the present invention.

First, the number of items in an access channel search queue (hereinafter, abbreviated as ACH-Q) is set as the remaining access channel count (remainAchCnt). The pointer pointing to MUL-Q as a link type is set to pMul95Link, and an arbitrary searcher index (hereinafter abbreviated as sIdx) of a variable is initialized to 0 (S11).

Subsequently, it is determined whether the variable sIdx is smaller than the number N of all the searchers (S12).

However, if the result of the determination (S12) is small, it is determined whether the search item of the searcher is null (S13). In this case, the search item of the searcher may be a full search for the channel, or may be null after being searched in the DBR on of the traffic multipath search.

As a result of determination (S13), if it is not null, a search command for the next sector or the next window of the search item is issued (S14), and the variable sIdx is increased by one (S15).

Subsequently, if the remaining number of access channels is greater than zero (S16), the access channel item is separated from the ACH-Q and set as the current search item CurrSrchItem, and the number of items of the ACH-Q is reduced by one. (S17).

Then, the remaining access channel count (remainAchCnt) is decreased by one (S18).

Next, it is determined whether the current time is the time for access channel search (S19). Here, the time to search the access channel is possible when the current arbitrary access frame index (AccessFrameIdx) is smaller than the access preamble size (AccessPamSize), and the time when the access channel was last searched completely (AchLastSrchDoneTime) is before the start time of the current slot. Do.

As a result of determination (S19), if the current time is the time to search the access channel, an execution command is issued to search the current search item (S20) and sIdx is increased by one (S15).

However, if the current time is not the access channel search time (S19), the current search item CurrSrchItem is put at the end of the ACH-Q (access channel queue) and the number of items of the ACH-Q is increased by one (S21).

Then, the variable sIdx is decreased by one (S22).

However, if it is determined in S16 that the number of remaining access channels is not greater than zero, it is determined whether the number of items in the PAM-Q (traffic preamble queue) is greater than zero (S23). The first search item is separated and set as the current search item (CurrSrchItem), and the number of items of PAM-Q is reduced by one (S24).                     

Subsequently, an execution command is given to the sIdx-th searcher to search for the current search item (S25).

However, if it is not large (S23), it is determined whether the traffic multipath search link is null (S26), and if it is null, it is returned.

However, if the determination result (S26) is not null, the next item (item) of the traffic multipath search link is obtained and set as the current search item (CurrSrchItem) (S27).

Subsequently, it is determined whether the current search item is null (S28), and if it is null, it is returned. If it is not null, it is determined whether the DBR of the current search item (CurrSrchItem) is on (S29).

If the determination result S29 is on, the current search item CurSSItem is removed from the MUL-Q and the number of items of the MUL-Q is reduced by one (S31).

Subsequently, the state of the sIdx-th explorer is run, so that the sIdx-th explorer searches for the current search item (CurrSrchItem) (S32).

Next, the next channel of the traffic multipath search link is set as the current search item (S33).

However, if the determination result (S29) is not on, the next channel of the traffic multipath search link is set as the current discovery channel (S30) and the process goes back to step S26.

3A and 3B are flowcharts illustrating a search done subroutine in the searcher operating method according to the present invention.

The search completion subroutine first initializes the variable sIdx to 0 (S40). At this time, bStartPartialsearch and bLastPartialSearch are initialized to FALSE, respectively.

Next, it is determined whether the variable sIdx is smaller than the number N of searchers, and returns if it is not small (S41).

However, if the determination result (S41) is small, it is determined whether the searcher is search done (S42), and if it is not search done, sIdx is increased by one (S43).

However, if it is determined that the search is completed (S42), the item assigned to the sIdx-th searcher is set as the current search item (CurrSrchItem), the number of search sectors (NumSrchSector), the current search window (CurrSrchWin), and the search in the search sector list. Information about a sector (CurrSrchSectorIdx) of one of sectors to be set is set as the current search item (CurrSrchItem) (S44).

Subsequently, it is determined whether the current search sector index CurrSrchSectorIdx is 0 and the current search window CurSSWin is 0 in the search information list of the current search item CurSrchItem (S45).

If the current search sector index (CurrSrchSectorIdx) is 0 and the current search window (CurrSrchWin) is 0, the partial search start (bStartPartialSearch) is set to TRUE (S46), and the current search window (CurrSrchWin) is determined. Rake-Width is increased (S47).

However, if it is not the determination result (S45), the current search window (CurrSrchWin) is increased by the rake width (RAKE-Width) (S47).

Next, it is determined whether the current search window CurSrchWin is equal to or larger than the search window size SearchSearchSize for the sector of the current search sector index CurrSrchSectorIdx of the search sector list SrchSectorList (S48).

If the determination result (S48) is large or equal, the current search window size (CurrSrchWin) is set to 0, and the current search sector index (CurrSrchSectorIdx) is increased by one (S49).

Subsequently, the current search sector index (CurrSrchSectorIdx) is compared with the number of search sectors (NumSrchSector) to determine whether it is greater than or equal to (S50). Set to true (S51).

Subsequently, it is determined whether the partial search (bStartPartialSearch) is started (S52). If the partial search is started, the search result is copied to the buffer of the current search item (S53). If the partial search is not started, the search result is updated in the buffer ( update) (S54).

Next, the search mode is determined (S55).

If it is determined in S55 that the discovery mode SrchMode is ACH or PAM, it is determined whether the partial search is the last (S56). If the determination is the last (S56), the current search item is put at the end of the current discovery mode queue (S57). The search item of the searcher is set to null (S58).

However, if the determination result (S55) is MUL, it is determined whether it is the partial search (S59), and if it is the last time, the current search item (CurrSrchItem) is put at the end of the current search mode queue (S60), and the search item of the explorer is Set to null (S62).

However, if the result of the determination (S59) is not the last, the current search item is put at the front of the current search mode queue (S61), and the search item of the searcher is set to null (S62).

As described above, the present invention can share N searchers in M-channel time division during search operation in an IS-95-A / B base station system among communication systems, and by using DBR information of each channel, The effect is that you can run the explorer much more efficiently.

Claims (4)

If the number of channels of the highest priority channel search queue is set to the number of remaining channels, and if any searcher index is smaller than the number of all searchers, it is determined whether the searcher has made a full search for the channel to be searched and the highest priority. Searching through all channels; If the searcher has searched for all of the highest priority channels, the searcher performs the next priority channel search until the channel being searched for the next priority channel search queue is null; And when the search for the next priority channel is completed, the searcher performs a channel search until the channel search for the next priority channel search queue becomes null. 2. The method of claim 1, wherein the highest priority channel discovery queue is a queue assigned to an access preamble discovery mode, the second priority channel discovery queue is a queue assigned to a traffic preamble discovery mode, and the third priority channel discovery queue. Is a queue assigned to the traffic multipath search mode. The method of claim 2, further comprising: if the searcher has not searched for the channel to be searched, issuing a search command for the next sector or the next window of the search item and increasing the index of the searcher. Explorer operation in a communication system. The method of claim 3, wherein the search item comprises items searched when the searcher performs the channel search according to the search mode.

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