KR20020071298A - Method for decoding bch message in mobile communication system using sttd - Google Patents

Abstract

PURPOSE: A method for demodulating a BCH(Broadcasting CHannel) message in a mobile communication system using a time space block coding transmission diversity is provided to certificate whether the block coding transmission diversity is transmitted and demodulate a broadcasting channel according to the certificated result. CONSTITUTION: Parameters of an STTD association hardware are set for processing a BCH message, and an optimum window search is performed for finger assignment by a multi-path(303). After a uniform time waits until an RTG(Reference Time Generator) identical to a frame timing of a finger 0 through a slam operation is stably operated, the STTD encoding certificated result is received from a combiner and a finger and an STTD association hardware is set on the basis of the received STTD encoding certificated result for demodulating the BCH message(305). If it is certificated whether the STTD encoding of a PCCPCH(Primary Common Control Physical CHannel) is performed, the multi-path is continuously searched for successfully demodulating the BCH message(307). If the demodulation of the BCH message is completed, it is transited from a BCH state to a PCH(Physical CHannel) state(309).

Description

Broadcast channel message demodulation method in mobile communication system using space-time block coding transmit diversity {METHOD FOR DECODING BCH MESSAGE IN MOBILE COMMUNICATION SYSTEM USING STTD}

The present invention relates to space-time block coding transmission diversity transmission of a mobile communication system, and more particularly, to a method for verifying whether the block coding transmission diversity transmission is performed and demodulating a broadcast channel according to the verification.

In the Universal Mobile Telecommunication System (UMTS), which is a third generation asynchronous transmission system, a primary synchronization channel is first applied when power is applied or when system timing, i.e., synchronization, is lost. PSCH, Secondary Synchronization Channel (SSCH), and Common Common Pilot Channel (CPICH) using a common pilot channel (CPICH) to obtain a synchronization after the primary common control physical channel transmitted from the base station to find the system information First Common Control Physical Channel (PCCPCH) must be demodulated first. A broadcast channel (BCH) message is mapped and transmitted to the PCCPCH. In the UMTS system, the base station may transmit the BCH message by STTD encoding to improve the reception performance of the terminal. In this case, the STTD encoding may be applied not only to the BCH channel but also to other channels such as a dedicated physical channel (DPCH) and a synchronization channel (SCH). By notifying the terminal whether the STTD is encoded, the terminal does not need to verify it separately. However, in the case of the BCH, the base station does not inform the terminal whether the STTD is encoded, so that the terminal needs to verify whether the STTD is encoded in order to receive the BCH message.

1 is a diagram illustrating the STTD transmission concept, and illustrates a pattern of channel bits for transmit diversity. When transmitting a BCH message by performing STTD encoding as shown in FIG. 1, the UE cannot receive the BCH message if it is not known whether the received BCH message is STTD encoded. To this end, in the UMTS standard, whether or not a BCH message is transmitted by being STTD encoded is transmitted by modulating a specific symbol of the PSCH and the SSCH. That is, the terminal may receive the BCH message by determining whether the BTT message is STTD encoded by detecting specific symbols of the PSCH and the SSCH.

2 is a diagram illustrating a method for notifying a terminal whether to transmit a BCH message by STTD encoding. Referring to FIG. 2, one symbol (for example, a symbol) is modulated and transmitted in every slot having a length of 256 chips of the PSCH and the SSCH. A denotes a symbol that the base station and the terminal know from each other, and if it is +1 (or -1), it indicates STTD transmission. If a -1 (or +1), it indicates that STTD transmission has not been performed. In FIG. 2, C _p is a primary sync code of the PSCH, and C _s is a secondary sync code of the SSCH.

As described above, in addition to the method of modulating and transmitting a specific symbol to the PSCH and the SSCH, there is a method of inserting and transmitting a layer 3 control bit indicating whether or not to be encoded in a BCH message. In this case, it is assumed that initial STTD transmission is performed and the layer 3 control bit should be detected. The terminal may selectively apply any one of the two methods.

However, the above methods have been proposed in the UMTS standard, and no specific operation method for implementing the above methods in the terminal is mentioned.

Accordingly, an object of the present invention is to provide a space time block transmission diversity transmission verification and demodulation method in a terminal of a mobile communication system.

In order to achieve the above object of the present invention, a broadcast channel message demodulation method in a mobile terminal of a code division multiple access mobile communication system having a search task and a layer 1 and a layer 3 includes a primary synchronization channel received from a base station. Or obtaining synchronization to transition to a broadcast channel state using a secondary synchronization channel; and when the synchronization is obtained, transition to the broadcast channel state to transmit a broadcast channel demodulation command to the search task. A process of performing a window search for finger allocation, and a hardware setting for demodulating a broadcast channel message according to space-time block coding transmission diversity when the finger is stabilized while waiting for a stable operation of a reference finger through a slam operation. Demodulating a broadcast channel message and optimizing the broadcast channel; It characterized by constituted by any process of continuously performing a multi-path search for demodulation.

1 is a diagram illustrating a general space-time block coded transmit diversity transmission method.

2 illustrates a transmission structure of a synchronization channel and a co-pilot channel

3 is a flowchart illustrating a method for demodulating a broadcast channel message in a mobile communication system using space-time block coding transmission diversity according to an embodiment of the present invention.

4 is a diagram illustrating a procedure between layer 1 and a search task for transitioning from an ACQ state to a broadcast channel state according to an embodiment of the present invention.

5 is a diagram illustrating a procedure between layer 1, layer 3, and a search task for transitioning from a DCH state to a broadcast channel state according to an embodiment of the present invention.

6 is a flowchart illustrating an event processing method in a standby substate and a path tracking substate for demodulating a broadcast channel message according to an exemplary embodiment of the present invention.

7 is a flowchart illustrating a frame boundary interrupt processing method of FIG.

8 is a flowchart illustrating a STTD_VERIFY_DONE interrupt processing method of FIG. 6.

9 is a flowchart illustrating a hardware setting method according to the STTD encoding change result of FIG. 6.

10 is a flowchart illustrating a SEARCH_DONE interrupt processing method of FIG. 6.

11 is a flowchart illustrating a method of processing an SRCH_STTD_F command of FIG. 6;

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, in adding the reference numerals to the components of each drawing, the same components have the same reference numerals as much as possible even if displayed on different drawings. In describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

All operations mentioned in the present invention are in charge of an entity called a "search task" in the UMTS UE algorithm. The search task refers to a task that acquires initial synchronization using a PSCH, an SSCH, and a CPICH and manages finger assignment and set maintenance through continuous CPICH search.

For call processing, the UE is largely divided into Layer 1 (Layer1: L1), Layer 2 (Lyer2: L2), and Layer 3 (Layer3: L3) according to its purpose and performance. Operations of the Search Task referred to in the present invention are included in the operation of the layer L1.

For call processing, each layer performs an interface using various kinds of primitives, and the search task interfaces with layer 1. At this time, layer 1 is operated in conjunction with layer 2 or layer 3 again. The interface between these layers is called signaling. In the following description of the present invention, signaling transmitted from a higher layer including layer 1 to a search task is referred to as a command, and a report transmitted from the search task to higher layers including L1 is reported. It is called). The report also includes a confirmation indicating that a command transmitted from higher layers has been properly performed. In addition, there are signaling with higher layers and an interface with a modem, and these methods may be implemented in a CPU or a DSP.

3 is a flowchart illustrating a method for demodulating a broadcast channel message according to STTD encoding verification according to an embodiment of the present invention. That is, FIG. 3 shows the "verification of SSTD encoding" and "the BCH message demodulation method performed after verification" of the PCCPCH. The state of the Search Task that performs the two tasks mentioned above is represented as BCH state for convenience in all diagrams.

The subject that issues the control command to perform the specific operation of the layer 1 becomes the layer 3, and in particular, the layer 1 generates the command by the triggering of the layer 3 to perform the above-mentioned operations by the search task transitioning to the BCH state. Deliver to the task. In the present invention, this command is expressed as SRCH_BCH_F (hereinafter referred to as a "broadcast channel demodulation command"). When the search task completes a specific task in the BCH state, it reports this to layer 1, and layer 1 informs layer 3 again. In response to the report, the layer 3 causes the layer 1 to send an SRCH_PCH_F command, which is an idle state transition command, to the search task in order to transition to the idle mode. The standby mode state transition command SRCH_PCH_F is a PCH state that is a state capable of receiving a Forward Access Channel (FACH), a Paging Channel (PCH), or an Acquisition Indicator Channel (AICH) message transmitted from a base station, and transitions the search task. This is the command of layer 1.

In the following description of the present invention, the name and function of the configuration according to the present invention is assumed to be the same as or corresponding to the configuration of the modem operating in the IS-95-A system. For example, a finger may be hardware that extracts and demodulates desired data from a signal received at a terminal through a wireless channel, estimates attenuation and distortion of the signal through the channel, and continuously tracks the timing of the received signal. In other words, a reference time generator (RTG) is a component that generates and manages its own timing of the UE. On the other hand, the register and its name, the variable and primitive (command, report) name, and other names such as interrupt for the control of the Modem are merely named for convenience of explanation of the operation of the present invention or for explaining the necessary functions. It should be noted that the configuration does not reflect specific modem chips or specific terminal configurations.

Entry into the BCH state is possible in the ACQ state and the DCH state. The ACQ state is a state in charge of the synchronization acquisition operation using the PSCH, SSCH, and CPICH, the DCH state is a state that performs a variety of operations required while the call to the base station. The transition from the ACQ state to the BCH state is a case of entering after completing synchronization acquisition, and the transition from the DCH state is a cell or sector selected to enter standby mode after the call is released. This is the case when entering to obtain the most recent system parameter information of sector).

3 is a flowchart illustrating a STTD encoding verification and BCH demodulation method in an ACQ state according to an embodiment of the present invention. A description with reference to FIG. 3 is as follows.

In step 3, step 301 is to set the initial state to enter the broadcast channel state. The initial synchronization state (ACQ State) of step 301 is obtained by using the PSCH, SSCH initial synchronization. When the initial synchronization is obtained, layer 1 reports that the initial synchronization is obtained to layer 3. Upon receiving this report, the layer 3 transmits a command to the layer 1 to demodulate the broadcast channel message, and the layer 1 generates a command corresponding to the command and transmits the command to the search task. In the present invention, the command transmitted to the search task is referred to as SRCH_BCH_F (hereinafter referred to as "broadcast channel demodulation command"). That is, when entering the ACQ state, after completing initial synchronization, CPICH timing acquisition, and frequency tracking operations, the search task reports SRCH_ACQ_R to Layer 1 and receives a broadcast channel demodulation command (SRCH_BCH_F) as an acknowledgment.

However, when entering from the DCH state, the layer 3 determines whether the call is terminated and then transmits the broadcast channel demodulation command through the layer 1, so that no state transition is made by the search task report. .

The transition from the ACQ state to the BCH state and the procedure from the DCH state to the BCH state are shown in FIGS. 4 and 5, respectively. Hereinafter, the transition procedure from the ACQ state and the DCH state to the BCH state will be described first with reference to FIGS. 4 and 5.

The search task 403 acquires initial synchronization through PSCH and SSCH in step 411 and transmits SRCH_ACQ_R, which is a command for reporting that the synchronization has been acquired, to the layer 1 401. In step 411, the layer 1 receiving the SRCH_ACQ_R command performs signaling with a higher layer, and in step 413, SRCH_BCH_F, which is a BCH state transition command for the SRCH_ACQ_R command, is transmitted to the search task 403.

However, in the DCH state, when the layer 3 (501) determines the termination of the call in the busy state, that is, the release of the traffic channel, the primitive indicating transition to the BCH state is transmitted to the layer 1 (503) in step 511. do. Upon receiving the primitive, the layer 1 503 transmits a broadcast channel demodulation command SRCH_BCH_F to the search task 507 in step 513.

In either case, when the search task receives the broadcast channel demodulation command, the BCH performs an automatic frequency control loop (AFC Loop) tracking mode setting process to transition to the BCH state, and then performs a BCH State transitions to states. In this case, since the AFC loop tracking mode setting process is stabilized through the frequency tracking operation in the ACQ state, the cross product period of the continuous phase frequency difference detector (CPFDD) is longer and the loop gain is increased. It can be made smaller.

When the transition from the broadcast channel state entry step 301 to the BCH state step 303 is performed, parameters of STTD related hardware are set for BCH message processing, and an optimal window search for finger assignment by multipath is performed. In the BCH state, the search task must handle events such as commands from higher ranks, interrupts from hardware, and configuration signals from the operating system. When a plurality of events occur, the search task is repeatedly performed until the BCH state ends according to a preset priority. The events handled by the search task are shown in Table 1 below.

event Origin / Priority action SRCH_START_F command Tier1 / 1 Transition command to start state when BCH message demodulation fails SRCH_PCH_F command Tier1 / 1 Successfully demodulate BCH message, command to transition to PCH state, perform window search and finger assignment for demodulating PCH, FACH or AICH message, maintain settings SRCH_STTD_F command Tier1 / 1 Determination of SCH symbol demodulation retry in Layer 1 based on a specific criterion when the SCH symbol 'a' value detected by the rake receiver for verifying the STTD encoding of the PCCPCH is different from the layer 3 message of the BCH. FRAME_BOUND Interrupt Combiner / 2 Interrupt signal generated by the combiner's RTG block, generated every 10 ms frame boundary STTD_VERIF_DONE Interrupt Combiner / 3 Interrupt signal generated by the combiner to demodulate the SCH symbol indicating whether the PCCPCH is STTD encoded by each finger to inform the DSP or CPU of the completion of symbol detection after combining. SEACH_DONE Interrupt Searcher / 4 Interrupt for the multipath searcher to inform the DSP or CPU that the window search is complete Lost-dump timeout signal Operating system / 5 Signal set by the operating system if no interrupt signal is issued from the multipath searcher to terminate the search until the lost dump timer expires after the search task issues a search command.

When the STTD_VERIFY_DONE interrupt is generated, a detected symbol value and a finger received Signal Code Power (RSCP) value should be stored in a corresponding register. The RSCP value will be used to determine the reliability of the detected symbol, that is, the erasure, and the deletion and the symbol detection value are reported as layer 1 and compared with the layer 3 message. When the STTD_VERIFY_DONE interrupt is generated, the search task sets a rake receiver based on the symbol value detected in hardware so that the BCH message is demodulated. The search task forcibly generates a SEARCH_DONE interrupt by considering the loss-dump timeout signal as a multipath searcher error. At this point, the search task receives and processes the window search result stored up to the point of interrupt occurrence.

When the BCH message is demodulated and decoded, CRC check and low-level data processing are performed. In this case, the CRC check and low-level data processing is performed by a receive (Rx) task that processes the traffic channel (TrCH) data output from the channel decoder, not the search task, so that the search task will deliver to layer 1 in relation to the message. There is no. However, the reception task detects and demodulates a symbol having a value of "+1" or "-1" transmitted after being modulated to a PSCH or an SSCH indicating whether or not STTD is encoded in FIG. 1 and transmitted to a search task. The search task demodulates a symbol using a correlation process through a Primary Synchronization Code (PSC) or a Secondary Synchronization Code (SSC) to verify whether the STTD is encoded, and if the result is +1, determines that the STTD is encoded. If 1, it is determined that it is not encoded. That is, the search task may report whether the STTD encoding is received from the receiving task to the layer 1. Table 2 shows the result reported by the hardware as Layer 1.

report SRCH_STTD_R parameter shape destination Explanation Symbol Boolean Tier 1 The SCH symbol value detected by the combiner is compared with a predetermined reference value and set to True if it is determined to be "+1" and to False if it is determined to be "-1". Perform comparisons and judgments on search tasks and report only the results Erase Boolean Tier 1 After combining the RSCP values of each finger, it compares with a predetermined reference value and reports "true" if the detected symbol value is unreliable if it is less than the reference value and "false" otherwise.

In the SCH state, not only the PCCPCH demodulation but also the optimal finger assignment through window search is continuously performed for the SCH symbol demodulation operation for verifying the STTD encoding of the channel. This can maximize diversity effect through optimal finger assignment and at the same time obtain an optimal channel estimate value from a pilot filter. This is because coherent demodulation of the SCH symbol based on the channel estimation value provides the best performance. The window search must be performed continuously in the BCH state, and hardware and software must be set before starting the actual window search. The hardware and software to be set may include a sector structure, a finger structure, a finger, a combiner, a searcher, a hardware interrupt, and an event process. Interesting Events).

The sector structure is an algorithmic structure that manages parameters required for search operation control of a searcher, stores search results, and manages related base station information. The sector structure is initialized for CPICH discovery in the BCH state. Main parameters include a scrambling code number, an OVSF code number, a set information, a sector position, and a window size. The OVSF code number is set to a code used for PCCPCH spreading, and a sector to which a BCH message is transmitted will be searched. The sector becomes an active set. On the other hand, when transitioning in the DCH state, the multiple environment may be a channel environment with a wide delay profile in the call state, and when transitioning in the ACQ state, to increase the probability of capturing the multipath around the path having the maximum energy. You must set a relatively large window size. The sector structure also sets parameters related to the search operation of the multipath searcher. Corresponding parameters include searcher gain, integration time, and asynchronous accumulation count. These parameters are also stored in the sector structure.

The finger structure is a structure that stores and manages parameters to be set in the finger and the state of the finger for demodulation of the received signal. The finger structure appropriately sets and stores parameters such as a time tracking loop gain and a lock threshold. The finger tracking time tracking and locking operation is performed by the set parameter value. In addition, the finger structure may copy and use parameters necessary for finger-end control, that is, a sector number, a scrambling code number, and an OVSF code number, from a sector structure to which an allocated path is transmitted during a finger assignment operation.

The finger sets the symbol rate of the PCCPCH to the finger end. In order to demodulate a symbol through OVSF code despreading, the symbol rate must be known at the fingertip.

The combiner sets the symbol rate of the PCCPCH to the combiner end. In order to combine the demodulated symbols at each finger at the correct time, the symbol rate must be known at the combiner stage. After resetting the RTG at the frame boundary of the first finger 0 generated in the future, the RTG commands to track the finger. This operation is called slam.

The searcher processes the search result transmitted from the multipath searcher in consideration of the search frequency in processing by the DSP or CPU.

The hardware interrupt checks frame boundary interrupts to perform a specific operation, and includes a connection of an interrupt service routine (ISR).

Interesting Event sets signals for events that must wait first in the wait state after entering an infinite loop for event handling.

After hardware configurations are set by the algorithm as described above, an infinite loop for event processing is performed.

After the above step 303, the process proceeds to the standby substate SS1_Wait of step 305. The idle state waits for a predetermined time until the RTG matched to the frame timing of the finger 0 is stably operated through a slam operation, and receives the STTD encoding verification result from the combiner and the finger. This is a state of configuring STTD related hardware for BCH message demodulation. At this time, continuous window search operation is required for STTD encoding.

If it is verified whether the PCCPCH has STTD encoded in the standby substate, it transitions to the path search substate (SS2_PATHTRACK) in step 307. The path search substate constantly searches for multipath for successful BCH message demodulation. For best demodulation performance, channel assignment is tracked and finger assignment is performed.

When demodulation of the BCH message is completed, that is, when the BCH is out of the BCH state, the process transitions to step 309, which is Actions for Entry into Paging Channel State in step 307. The call channel transition preparation substate is a process for transitioning from the BCH state to the PCH state. In FIG. 3, only the transition to the BCH state is illustrated, but the transition to the START state may be performed.

According to the present invention, a method for demodulating a BCH message is performed in the standby substate 305 and the path search substate 307. Accordingly, an infinite loop for processing the events is also performed in steps 305 and 307.

6 is a flowchart illustrating an event processing procedure for demodulating a BCH message in a BCH state. A description with reference to FIG. 6 is as follows. Since the execution subject of the event processing process is a DSP or a CPU, the execution subject will be described as a control unit in the following description of the present invention.

After the steps 301 and 303 of FIG. 3 are performed, the controller determines whether the current state is the BCH state in step 605. If the current state is the BCH state, the controller proceeds to step 607 and otherwise ends the BCH state. In step 607, the controller checks whether a command is input from the L1 layer. In step 607, if a command is received from the L1 layer, it is determined in step 609, step 613 and step 617 what command the input command is. In step 609, it is determined whether the SRCH_START_F command of Table 1 is present. If the command input in step 607 is the SRCH_START_F command, the control unit proceeds to step 611 and transitions to a start state. No commands are sent to the search task in the standby state. However, if an unwanted event occurs in the upper layer or another task, the SRCH_START_F command is sent to the search task. However, if the input command is not the SRCH_START_F command, it is determined whether the SRCH_PCH_F command is performed in step 613. If the command is the SRCH_PCH_F command, the process proceeds to step 615 and the state transitions to the PCH state. In step 617, it is determined whether the input command is an SRCH_STTD_F command. If the inputted command is an SRCH_STTD_F command, the process proceeds to step 619 to set the environment of components related to STTD encoding. However, if the SRCH_STTD_F command is not present, the controller proceeds to step 621 to notify the state 1 that the state is not good. After performing steps 611, 615, 619, and 621, the process returns to step 605 to repeat the subsequent steps.

If a command is not input from layer 1 in step 607, the controller checks whether an event occurs in steps 623, 627, 631, and 635. First, in step 623, it is checked whether a frame boundary interrupt occurs. If the frame boundary interrupt occurs, the controller proceeds to step 625 to perform frame boundary event processing and returns to step 605. If the frame boundary interrupt does not occur in step 625, the controller checks whether an STTD_VERIFY_DONE interrupt occurs in step 627. If the STTD_VERIFY_DONE interrupt occurs in step 627, the controller proceeds to step 629 to perform the operation described in Table 1 above, and returns to step 605 to repeat the subsequent process. That is, when the pilot filter output used in the STTD encoding verification operation at the finger end has a reliable value, the interrupt is enabled and added to the Interesting Event at the same time. If the STTD_VERIFY_DONE interrupt does not occur in step 627, it is checked in step 631 whether the SEARCH_DONE interrupt occurs. If the SEARCH_DONE interrupt occurs, the controller proceeds to step 633 to perform optimal finger assignment as described in Table 1 above, and returns to step 605 to repeat the process. In step 635, it is checked whether the loss-dump timer has exceeded a predetermined time. If the lost-dump timer exceeds the predetermined time, the controller proceeds to step 637 to perform a timeout process and returns to step 605 to repeat the process. However, if the Lost-Dump Timer does not exceed the predetermined time, the next event waits for generation of the next event and returns to step 605 to repeat the subsequent process.

FIG. 7 is a flowchart illustrating a method of processing the frame boundary (FRMAE_BOUND) interrupt in step 625 of FIG. Hereinafter, a method of processing a frame boundary interrupt will be described in detail with reference to FIG. 7.

If the frame boundary interrupt occurs in step 623 of FIG. 6, the controller performs step 701. In step 701, after the slam is commanded to the RTG, the interrupt is first generated at the frame boundary of the first finger 0, which is generated. Then, it is checked whether the counted value exceeds the N value which is a sufficient number of counts so that the RTG operation is stabilized. If the counted value does not exceed the N value, the controller proceeds to step 703 and appropriately sets hardware to detect the SCH symbol for STTD encoding. After performing step 703, the controller proceeds to step 705. In step 705, the controller allocates a window search command to the multipath searcher because it needs to perform finger assignment through multipath search for demodulation and combining of SCH symbols. The search command includes an operating system signal, software variables, a searcher related register, a loss-dump timer, and a searcher-rate governor.

The operating system signal is a signal for notifying the search task when an interrupt occurs when the window search is completed. Therefore, at this point, the ISR signal set by the OS must be cleared. The register-related registers include registers that write gain values, cumulative time chips, asynchronous accumulation counts, and window size (number of hypotheses) used in the correlation operation of the searcher, and the amount that the scrambling code generator should slew from the current position. There are registers to write to. The slew means changing the state of the scrambling code generator to a specific state different from the present. In other words, the slew is to change the timing of the scrambling code generator. The values written to the searcher related registers use the values stored in the variables in the sector structure. Lost-dump timer is shown in Table 1 above. The searcher rate adjuster controls the searcher rate when performing a window search. If the searcher performs a search at a higher search frequency than the set search rate, the control timer may be appropriately maintained by setting an adjustment timer to insert a delay of a predetermined operating system.

The process is repeated until the counted value is greater than the N value. If the counted value is repeated as much as the N value, the controller proceeds to step 707 to determine whether the frame boundary has elapsed MN times after the RTG slam command, that is, the hardware setting operation for detecting the SCH symbol. . If the M-N times is exceeded, the controller proceeds to step 709 to enable the STTD_VERIFY_DONE interrupt. The reason for obtaining the detection result after waiting M-N times further in step 707 is to wait enough time until the reliable channel estimation value is output from the pilot filter after the multipath is assigned to the finger. Since it will wait for the interrupt, it must be added to an Interesting Event.

FIG. 8 is a flowchart specifically illustrating a STTD_VERIFY_DONE interrupt processing process of FIG. 6. A description with reference to FIG. 8 is as follows.

When the STTD_VERIFY_DONE interrupt is generated from layer 1 in step 627 of FIG. 6, the control unit obtains verification results such as a RSCP value of the finger and a symbol value from the combiner from the corresponding register in step 803. When the verification result values are obtained, the controller proceeds to step 805 and determines that the symbol detection operation is not to be performed anymore, and disables the STTD_VERIFY_DONE interrupt. If the STTD_VERIFY_DONE interrupt is disabled, the controller releases the hardware configurations for STTD encoding verification in step 807. After canceling the configuration of the hardware configuration, the process proceeds to step 809 to set the rake receiver based on the detected symbol value so that the BCH message is demodulated. The symbol value is determined to be +1 or -1 by comparison with a predetermined reference value, and in the case of the RSCP value of the finger, it is determined to be deleted if it is smaller than the RSCP reference value. Even when the channel condition is determined to be deleted due to poor channel conditions, the PCCPCH is assumed to be STTD encoded and the data will be demodulated because the BCH message must be demodulated regardless of the channel condition.

When the BCH message is demodulated in step 809, the controller reports the result of the SCH symbol detection and whether it is deleted to layer 1 in step 811. After step 811, the control unit maintains an optimal finger assignment state while demodulating the PCCPCH in the rake receiver. In step 813, the controller transitions to the path tracking substate to perform continuous window searching.

9 illustrates a BCH message demodulation method according to an embodiment of the present invention. The BCH message demodulation is performed after step 803 of FIG.

After the operation 803 is performed, the controller determines whether the STTD encoding result is acquired from the hardware and the RSCP value of the finger is greater than the deletion reference value in steps 901 and 903 of FIG. 9. If the finger RSCP value is greater than the deletion reference value, the controller proceeds to step 905 and, if small, to step 907. In step 905, it is determined whether the SCH symbol value is larger than a symbol reference value. If the SCH symbol value is larger than the symbol reference value, the controller proceeds to step 907. In step 907, hardware configurations are set for modulation of the STTD encoded PCH. However, if the SCH symbol value is smaller than the symbol reference value in step 905, the controller proceeds to step 909 to set hardware configurations for PCCPCH modulation that does not use diversity.

FIG. 10 is a detailed flowchart illustrating the SEARCH_DONE interrupt processing process of FIG. 6. Hereinafter, a SEARCH_DONE interrupt processing process will be described with reference to FIG. 10.

When the SEARCH_DONE interrupt is generated from the layer 1, the control unit reads the window search result and the finger state from the registers in step 1003. In order to read the window search result, it is necessary to change searcher related registers and algorithm variables. The search for the searcher related registers reads a register that stores the position of the scrambling code generator when the window search is completed and stores it in a variable in the sector structure. The register stores the position at the time of the most recent status dump. The n peak energies and indices captured in the window are read and stored in variables in the sector structure. Captured peak paths are used for finger assignment. The algorithm change is appropriately set if there are software variables related to the start and end of the window search. The processing of the finger related registers reads the finger position, finger RSCP and finger lock states at the latest status dump from the corresponding register and stores them in a variable in the finger structure.

After the process, the controller performs optimal finger assignment according to the read window search result and the finger state in step 1005. When the finger assignment is made, in step 1007, a command for restarting the window search for continuous multipath tracking is generated.

As described above, in order to demodulate the BCH message in the path tracking substate after the PCTTCH encoding of the STTD is verified in the standby substate, the continuous multipath is searched. Finger assignment is performed by tracking channel conditions for best demodulation performance.

Events that can occur in the path trace sub-state include SRCH_START_F command, SRCH_PCH_F command, STCH_STTD_F command, STTD_VERIFY_DONE interrupt, SEARCH_DONE interrupt, and Lost-dump timeout signal. The description of the events which perform the same operation as the standby substate is omitted.

11 is a flowchart showing a SRCH_STTD_F command processing procedure. Hereinafter, an SRCH_STTD_F command processing process will be described with reference to FIG. 11.

In a situation where the SCH symbol value detected by the rake receiver is different from the L3 message of the BCH in order to verify whether the PCCPCH is STTD encoded, the command SRCH_STTD_F is transmitted when L1 decides to retry SCH symbol demodulation. In step 1103, the controller appropriately sets hardware to detect the SCH symbol for STTD encoding. When the hardware is set, the controller enables the STTD_VERIFY_DONE interrupt in step 1105 to receive the detection result from the hardware. This is again enabled at this point because the STTD_VERIFY_DONE interrupt is disabled while escaping the standby substate.

When the process is completed, the rake receiver waits for the SCH symbol detection result. In this case, it is necessary to ignore the detection result of the symbol when the hardware configuration for symbol detection is performed within a symbol interval of an arbitrary slot. To compensate for this situation, a method of ignoring the detection result for a certain number of slots after hardware configuration may be used. Subsequent processing for the STTD_VERIF_DONE interrupt, which occurs whenever symbol detection from the rake receiver is completed, is shown in FIG. When attempting to demodulate data transmitted on any channel with the best performance or a certain level of performance, finger assignment through continuous window searching is essential. This is true even if the rake receiver demodulates the PCCPCH in the path tracking substate. When the window search is completed in the path tracking sub-state, subsequent processing is performed by the process of FIG. That is, the same processing as in the standby substate is performed.

When the user exits the BCH state, that is, when transitioning from the BCH state to the start state or the PCH state, if there is a window search operation of the multipath searcher currently in progress, wait until the completion and discard the search result. In addition, when the BCH message is successfully demodulated, the window position where the multipath search was performed is stored. This can be used when the UE has lost timing.

By applying the software algorithm designed in the present invention to the terminal for UMTS, it verifies whether the SCPD encoding of the PCCPCH transmitted from the UMTS base station and also controls the Modem for the actual BCH message demodulation to be performed after the STTD encoding is verified. can do.

Claims (12)

A broadcast channel message demodulation method in a mobile terminal of a code division multiple access mobile communication system having a search task and a layer 1 and a layer 3, Acquiring synchronization using a synchronization channel received from a base station; When the synchronization is obtained, transmitting, by the layer 3, a broadcast channel demodulation command to the search task to perform a window search for optimal finger assignment; Performing a stable operation of the reference finger through the slam motion, Demodulating a broadcast channel message by setting hardware to demodulate a broadcast channel message according to space-time block coding transmission diversity when the finger is stabilized; And continuously performing a multipath search for optimal demodulation of the broadcast channel. The method of claim 1, wherein the window searching process for optimal finger assignment is performed. Checking whether a command is received from the layer 1 in the broadcast channel state; Performing a state transition according to the command when a command is received from the layer 1; Checking whether interrupts occur if a command is not received from the layer 1, and performing an operation on the interrupt when a specific interrupt occurs. The method as claimed in claim 2, wherein the commands that may occur in the layer 1 are a broadcast channel message demodulation failure command SRCH_START_F, a broadcast channel message demodulation success command SRCH_PCH_F, and a broadcast channel message demodulation retry command SRCH_STTD_F. . 4. The method of claim 3, wherein if the command generated in the layer 1 is a broadcast channel message demodulation failure command, the method transitions to a start state. 4. The method of claim 3, wherein if the command generated in the layer 1 is a broadcast channel message demodulation success command, the method transitions to a paging channel state. 4. The method of claim 3, wherein if the command generated in the layer 1 is a broadcast channel message demodulation retry command, time-space block coding transmit diversity related configurations are set. The method of claim 2, wherein the interrupts are a frame boundary (FRAME_BOUND) interrupt, a symbol detection complete (STTD_VERIFY_DONE) interrupt, and a window search completion (SEARCH_DON) interrupt. 8. The method of claim 7, wherein if the generated interrupt is a frame boundary interrupt, the frame boundary event is processed. 8. The method of claim 7, wherein the space-time block coding transmit diversity encoding process is performed if the generated interrupt is a symbol detection completion interrupt. 8. The method of claim 7, wherein if the generated interrupt is a window search complete interrupt, finger assignment is performed. The method of claim 8, wherein the frame boundary event processing, Searching for multipath for space-time block coding transmit diversity until N frames are exceeded after the slam operation, And enabling a symbol detection completion interrupt after passing a predetermined frame after the N frame has been exceeded. A broadcast channel message demodulation method in a mobile terminal of a code division multiple access mobile communication system having a search task and a layer 1 and a layer 3, Requesting the base station to release the traffic channel during the traffic channel establishment, and transitioning to the broadcast channel state by a primitive received in response thereto; The layer 1 receiving the primitive and transmitting a broadcast channel demodulation command to the search task to perform a window search for optimal finger assignment; Demodulating a broadcast channel message by setting hardware for demodulating a broadcast channel message according to space-time block coding transmission diversity when the finger is stabilized and waiting for a stable operation of a reference finger through a slam operation; And continuously performing a multipath search for optimal demodulation of the broadcast channel.