JP2007329758A - Radio base station apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure notification information and a signal level of a peripheral base station apparatus when a radio base station apparatus is started, and to automatically set a diffusion code, transmission power, etc. necessary for installing the radio base station apparatus. <P>SOLUTION: The radio base station apparatus is provided with an up individual channel baseband receiving part 20, an up common channel baseband receiving part 30, a down individual channel baseband transmitting part 40, and a down common channel baseband transmitting part which are baseband function parts and a down common channel receiving part 70 to be driven when the base station apparatus is started. In the case of starting the base station apparatus, the down common channel receiving part 70 which is different from the baseband receiving parts 20, 30 which are normal base station receiving function parts to measure notification information and a signal level of the peripheral base station apparatus. On the basis of the measured result, a diffusion code, transmission power, etc. which are necessary for installing the base station apparatus itself are automatically set in the baseband function parts. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radio base station apparatus using a CDMA (Code Division Multiple Access) type radio communication system.

Conventionally, a radio base station apparatus using a CDMA radio communication system performs the following control.
In a radio base station apparatus in the same radio access system, the service area covered by each base station apparatus depends on conditions such as channel capacity of the base station apparatus and transmission power level, and various zone configurations are assumed. . For this reason, when installing a radio base station apparatus, it is necessary to measure the environmental conditions peculiar to the place where the radio base station apparatus is installed, and to make a zone configuration based on base station arrangement design so as not to cause interference problems with other base station apparatuses. Specifically, setting of carrier frequency used in installed base station apparatus, setting of maximum transmission power, selection of scramble code used in spread modulation during downlink signal transmission set in units of sectors of base station apparatus Is raised. Conventionally, these settings are base station information set in units of base stations to be installed, or in the case where the base station device is configured in zones with a plurality of sectors, and are suitable for the environment at the time of zone configuration A parameter list is created and assigned to each base station device.

  In the base station apparatus, parameters stored in the base station apparatus in advance according to the installation location (hereinafter referred to as base station data) and radio network control that is a host apparatus at the start of operation of the base station apparatus (Cell Setup) Using the parameters set by the device (RNC: Radio Network Controller), the radio resource and device configuration of the base station device corresponding to the radio zone configuration are determined and the operation is started.

  In communication between a mobile station and a base station apparatus in a wireless communication system, for example, when a transmission request from a mobile station is generated, control information is transmitted and received using a common channel, and parameters necessary for setting an individual channel are shared. Then, when radio resources necessary for dedicated channel setting and channel resources of the base station apparatus can be secured, dedicated channel setting is performed and user data communication is started. For this reason, at the start of operation of the base station device, first, a common channel is set, and transmission power at a level at which communication with the wireless portable terminal device depending on the area covered by the base station device is applied.

  The configuration of the baseband unit of the radio base station apparatus includes a target channel for reporting information on a service area (cell) configured by the base station apparatus to a mobile station located in the cell, and acceptance of a new call , Resources for a common channel used for transmitting control information used for setting to the base station apparatus, and transmission of data and control information on a one-to-one basis between the mobile station and the base station apparatus Consists of resources for dedicated channels to perform.

  FIG. 4 is a block diagram illustrating a configuration example of a conventional radio base station apparatus. The radio base station apparatus includes a wired transmission path interface (IF) section 11 connected to a host apparatus (RNC), a frame protocol (FP) processing section 12 that performs frame protocol processing necessary for interface with the wired transmission path, A call control unit 13 that performs call control, a radio unit 14 that communicates with a mobile station, a reception memory 15 that holds sampling data of uplink reception data output from the radio unit 14, and data that is stored in the reception memory 15 A baseband receiving unit 20 for uplink dedicated channel that performs baseband reception processing for the uplink dedicated channel, and a baseband for the uplink common channel that performs baseband reception processing for the uplink common channel based on the data held in the reception memory 15 Downlink dedicated channel data processed by the receiving unit 30 and the frame protocol processing unit 12 The baseband transmission unit 40 of the downlink dedicated channel that performs coding and modulation processing on the baseband of the downlink common channel that performs coding and modulation processing on the data of the downlink common channel processed by the frame protocol processing unit 12 A spread processing unit that performs spread modulation processing on downlink data output from the transmission unit 50, the baseband transmission unit 40 of the downlink dedicated channel, and the baseband transmission unit 50 of the downlink common channel using a predetermined spreading code and outputs the result to the radio unit 14 16 is provided.

  The uplink dedicated channel baseband receiving unit 20 includes a control channel despreading unit 21, a data channel despreading unit 22, a demodulating unit 23, a demodulated data memory 24, and a decoding unit 25.

  The uplink common channel baseband receiving unit 30 includes a control channel despreading unit 31, a data channel despreading unit 32, a demodulation unit 33, a demodulated data memory 34, and a decoding unit 35.

  The downlink dedicated channel baseband transmission unit 40 includes an encoding unit 41 and a modulation unit 42.

  The downlink common channel baseband transmission unit 50 includes an encoding unit 51 and a modulation unit 52.

  The radio base station apparatus configured as described above is connected to the host apparatus (RNC) via the wired transmission path interface unit 11. When the base station is started up, the call control unit 13 first sets necessary wired transmission line related parameters from the base station data, and further sets the operation start data (Cell Setup data) set from the host device (RNC) to the radio unit. 14 and the baseband signal processing unit. The parameter set in the radio unit 14 includes the frequency number of the carrier to be used. For the baseband signal processing unit, the parameters of the pilot channel (CPICH) serving as a reference for the downlink common channel timing and transmission power are set. Also, a scramble code is set when the downlink data from the base station apparatus is spread-modulated.

Next, an initial parameter setting method in a conventional radio base station apparatus that communicates with a plurality of mobile stations (terminal apparatuses) will be described.
In recent years, with the increase in the number of users of terminal devices, a method of reducing the cell size per base station device 61 as shown in the zone configuration example of FIG. In FIG. 5, reference numeral 61 denotes a plurality of radio base station apparatuses each having a micro cell area 62, and a plurality of radio base station apparatuses 63 having a macro cell area 64 exist in the vicinity thereof.

  As described above, in recent years, with the increase in the number of users of terminal devices, the micro cell system has been adopted, and further downsizing of cells has been performed. In this case, there is a characteristic that it is relatively susceptible to the influence of structures such as topography and buildings and the influence of external interference of surrounding cells. In particular, in the case of the CDMA system, the amount of interference power consisting of the internal interference 65 from the terminal device existing in the cell and the external interference 66 from the neighboring cell greatly depends on the channel capacity of the base station device. From the above viewpoints, it is important to select an appropriate base station configuration and setting parameters suitable for the surrounding environment, particularly when a zone is configured by a small-scale radio base station device.

Also, as a known technique related to the present invention, a radio base station apparatus, a radio base station control apparatus that controls the radio base station apparatus, and a radio base station setting apparatus that sets communication specifications of the radio base station apparatus are included. In the radio base station apparatus setting system, when the radio base station setting apparatus receives the setting request notification message from the radio base station apparatus, the radio base station apparatus sets the radio base station apparatus from information stored in its own information storage unit Information on the wireless base station apparatus is estimated, and the communication specifications of the existing wireless base station apparatus existing around the estimated position are read from its own information storage unit, and the read existing A technique for determining the communication specifications of the radio base station apparatus based on the communication specifications of the radio base station apparatus and the estimated position (see, for example, Patent Document 1), In a W-CDMA cellular phone system having a base station and a base station controller that controls the plurality of radio base stations, the radio base station receives radio signals from other radio base stations, and receives the radio signals. Processing to identify the control channel of the other radio base station, determine the downlink scrambling code of the radio signal from the other radio base station from this control channel, and in the base station controller, from the radio base station A technique is known in which a downlink scrambling code of a radio base station that has transmitted the determination result is determined based on the determination result (see, for example, Patent Document 2).
JP 2005-328152 A JP 2003-219478 A

  According to the initial parameter setting method of the base station apparatus of the prior art shown in FIG. 4 above, when parameters suitable for the place of installation and environment are determined in advance, the stored parameters and the host apparatus (RNC) Various parameters to be set are set in the wireless unit 14, the wired transmission path interface unit 11, and the baseband signal processing unit to start operation. On the other hand, when the location where the base station device is installed is not specified in advance and the base station is installed to give the installation location flexibility and the operation is started, appropriate parameters are set in advance. Is difficult to store. In particular, when assuming a small base station device with a relatively small number of terminal devices that can be accommodated, when applying fixed initial parameters without considering the location-dependent environment to be used, the base station device It is easily assumed that proper operation cannot be performed due to interference or the like in communication and communication between the peripheral base station apparatus and the terminal apparatus.

  First, focusing on the scramble code applied when spreading the downlink signal of the base station device, the terminal device first identifies the scramble code number arranged for each cell, measures the reception level of the common channel, The optimal base station device that can be accessed by the device is selected. For example, if the installed base station device uses the same scramble code number as the surrounding existing base station device, there is a problem that the cell cannot be identified. appear.

  In addition, a fixed transmission power is applied to the pilot channel (CPICH) and the broadcast channel from the base station apparatus, but if the appropriate power value corresponding to the area covered by the base station apparatus is not selected, the neighboring base station Since this affects the terminal device that is communicating with the device as interference, the communication quality is degraded.

  The CDMA system is characterized in that the same frequency can be used between adjacent cells. However, when different frequencies are used in the zone configuration, the influence of external interference can be suppressed. However, when different frequencies are arbitrarily arranged, if they cannot be accommodated in the handover destination base station apparatus, forced disconnection occurs, which causes a problem in terms of the call loss rate. In addition, when a zone shift is normally performed at the same frequency, the diversity effect by soft handover using a plurality of channels of another cell and the own cell at the same time cannot be obtained by a hard handover at the time of zone shift by a different frequency.

  Further, in the invention of Patent Document 1, when the radio base station setting device receives the setting request notification message from the radio base station device, the radio base station setting device estimates the position of the radio base station device and surrounds the estimated position. Read the existing wireless base station device communication specifications from its own information storage unit, and based on the read existing wireless base station device communication specifications and the estimated position, the communication specifications of the wireless base station device Since it is determined and the peripheral base station device is not searched autonomously, information in the actual environment where the radio base station device is installed cannot be obtained. Further, when the radio base station apparatus is connected to the radio base station control apparatus, the radio base station apparatus receives peripheral base station information from the radio base station control apparatus, and based on that, receives a downlink signal of another base station apparatus and measures a signal level. Although the measurement result is used for position detection, since the area configuration is set by the user, it is difficult to perform an optimal area configuration in consideration of overhead and interference from other base station apparatuses.

  In the invention of Patent Document 2, the radio base station determines the downlink scrambling code of the radio signal from another radio base station, and the base station controller determines the downlink scrambling code of the radio base station. However, the base station information other than the scramble code is not considered.

  The present invention has been made in order to solve the above-described problems. In a small-scale zone configuration in which a user can freely install a base station device, the wireless access depends on the location where the wireless base station device is installed. In order to obtain the installation status and radio wave propagation status of other neighboring base station devices according to the system, the baseband signal processing is switched to processing for receiving downlink signals from other base station devices when the device is started up. It is an object of the present invention to provide a radio base station apparatus that can automatically set a spreading code, transmission power, and the like necessary for installing the base station apparatus by measuring broadcast information and a signal level.

  A radio base station apparatus according to a first invention includes a radio unit that performs radio communication with a mobile station, a reception memory that stores reception spectrum spread data that is received and sampled sequentially by the radio unit in units of samples, A baseband receiver that processes and decodes reception data stored in the reception memory, and a downlink that is activated when the apparatus is started up and receives downlink signals of other base station apparatuses from the reception data stored in the reception memory. A common channel reception unit and a wired transmission line interface to a higher-level device, frame protocol processing for the interface with the wired transmission line, the upstream signal received by the baseband reception unit and from the higher-level device Frame protocol processing means for converting a transmission channel format for a downstream signal, and the frame protocol A baseband transmitter that encodes and digitally modulates and outputs downlink data output from the processing means; and a spread processor that performs spread modulation processing on the data output from the baseband transmitter and outputs the processed data to the radio unit A call control unit that controls allocation of processing resources of each functional unit when a new call is received in the base station device, and activates the downlink common channel reception unit when the device is started up. Broadcast information and signal level are measured, and based on the measurement results, settings such as spreading codes and transmission power necessary for installing the base station apparatus are automatically performed.

  According to a second aspect of the present invention, there is provided a radio base station apparatus that performs radio communication with a mobile station and other radio base station apparatuses, and samples received spectrum spread data sequentially received and sampled by the radio section. A reception memory for storing in units, a baseband receiving unit for processing and decoding the reception data stored in the reception memory, and a wired transmission line interface for a host device, for the interface with the wired transmission line Frame protocol processing means for performing frame protocol processing and converting the transmission channel format for the upstream signal received by the baseband receiver and the downstream signal from the higher-level device, and the downstream output from the frame protocol processing means A baseband transmitter that encodes data, digitally modulates and outputs the data, and the baseband A spread processing unit that performs spread modulation processing on data output from the transmission unit and outputs the processed data to the radio unit, and a call control unit that controls allocation of processing resources of the functional units when receiving a new call in the base station apparatus And switching at least part of the baseband signal processing to processing for receiving downlink signals of other base station devices when the device is started up, searching for neighboring base station devices, and when valid cells are detected, The frequency used by the radio unit for transmission is set to be the same as the frequency of the cell, and the spreading code used by the spreading processing unit is set differently from the spreading code of the cell.

  According to a third aspect of the present invention, in the radio base station apparatus according to the first aspect of the present invention, the wireless base station apparatus has a wired interface function for a control signal with a modular terminal apparatus that normally performs communication with the base station apparatus, and a communication protocol. The control is set for the terminal device, and the downstream signals of the neighboring base station devices are modularized in order to acquire the installation status and radio wave propagation status of other base station devices using the same radio access method required when installing the base station device The information is received using the received terminal device, the broadcast information of the neighboring base station device and the signal level are measured, and the setting of the spreading code, transmission power, etc. necessary for installing the own base station device is automatically performed. And

  According to the present invention, when a radio base station apparatus is installed in a scaled-down zone configuration in which a user can freely install a radio base station apparatus, the downlink common channel reception unit is activated when the apparatus is started up, or the base By switching the band signal processing to processing for receiving downlink signals from other radio base station devices, the base station device-specific parameters including the scrambling code and frequency appropriate for the surrounding cell environment are independently selected and set. be able to. Further, in the wireless network as shown in the embodiment, dozens of wireless base station devices are arranged with respect to the higher-level device. Therefore, the upper-level device collectively manages the peripheral base station information, and stores each base station information. It is possible to reduce the load on the host device as compared with the case of setting and controlling. Further, since it has an initial cell search function equivalent to that of the terminal device, it is possible to acquire peripheral base station information in a more actual installation environment.

  Further, since it is not necessary to determine the neighboring base station and determine the scramble code in the setting device, the system configuration is simplified. Also, assuming a home use base station, it is assumed that frequent installation changes are performed, and concentration in a host device that does not select and set autonomous base station parameters as in this embodiment. In the case of management, if the periphery of the installed base station is only a fixed base station, it can be determined that the peripheral base station exists in the vicinity of the base station. Since the neighboring base station information is frequently updated when it is a use, the control of the host device becomes complicated, and the effect of the configuration in which the determination is made autonomously within the base station and only the notification is given to the host device is large.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The same parts as those of the conventional apparatus shown in FIG.

  FIG. 1 is a block diagram illustrating a configuration example of a baseband unit of a radio base station apparatus according to an embodiment of the present invention. The radio base station apparatus includes a wired transmission path interface (IF) section 11 connected to a host apparatus (RNC), a frame protocol (FP) processing section 12 that performs frame protocol processing necessary for interface with the wired transmission path, A call control unit 131 that performs call control, a radio unit 14 that communicates with a mobile station, a reception memory 15 that holds sampling data of uplink reception data output from the radio unit 14, and data that is stored in the reception memory 15 A baseband receiving unit 20 for uplink dedicated channel that performs baseband reception processing for the uplink dedicated channel, and a baseband for the uplink common channel that performs baseband reception processing for the uplink common channel based on the data held in the reception memory 15 Data of the downlink dedicated channel processed by the receiving unit 30 and the frame protocol processing unit 12 The baseband transmission unit 40 of the downlink dedicated channel that performs encoding and modulation processing on the data, and the base of the downlink common channel that performs encoding and modulation processing on the data of the downlink common channel processed by the frame protocol processing unit 12 Spreading process in which downlink data output from the band transmission unit 50, the baseband transmission unit 40 of the downlink dedicated channel, and the baseband transmission unit 50 of the downlink common channel is subjected to spread modulation processing with a predetermined spreading code and output to the radio unit 14 And a downlink common channel receiver 70 that is activated when the base station apparatus is started up.

  The call control unit 131 has a resource management function for controlling the allocation of processing resources of the radio unit 14 and each baseband signal processing unit when a new call is received in the base station apparatus.

  The uplink dedicated channel baseband receiving unit 20, the uplink common channel baseband receiving unit 30, the downlink dedicated channel baseband transmitting unit 40, and the downlink common channel baseband transmitting unit 50 are the same as those shown in FIG. It is the same composition as.

  The downlink common channel reception unit 70 includes a downlink common channel synchronization unit 71, a despreading unit 72, a demodulation unit 73, a demodulated data memory 74, and a decoding unit 75, and the sampling data held in the reception memory 15 is synchronized. Data input to the unit 71 and the despreading unit 72 and decoded by the decoding unit 75 are sent to the frame protocol processing unit 12. The downlink common channel receiver 70 is activated at the time of starting up the device in order to acquire the installation status of other base station devices according to the same radio access method and the radio wave propagation status depending on the location where the base station device is installed, Receiving downlink signals from other base station apparatuses, and measuring broadcast information and signal levels of neighboring base station apparatuses.

In the radio base station apparatus configured as described above, first, a processing operation when performing normal operation will be described.
The wireless unit 14 sequentially samples and A / D (analog / digital) converts uplink reception data, that is, reception spectrum spread data, in communication with the mobile station, and stores sampling data having a plurality of word lengths in the reception memory 15. Store in sample units. The reception data stored in the reception memory 15 is input to the control channel despreading unit 21 and the data channel despreading unit 22 of the baseband receiving unit 20 of the uplink dedicated channel.

  The control channel despreading unit 21 generates a spreading code applied at the time of spreading modulation on the transmission side with respect to a control channel storing control information such as transmission power control parameter and transmission format for each channel, Perform despreading processing. Further, the control channel despreading unit 21 calculates a phase rotation amount based on a known pilot pattern to be inserted, and uses it for data symbol detection and phase compensation. A pilot signal for demodulation is inserted in the data on the control channel side. The pilot has a predetermined insertion position in the frame and a pattern of “1” / “0”, which is a known symbol pattern on the transmitting side and the receiving side. The amount or the like can be calculated and used in the demodulator 23 as information for synchronous detection.

  The data channel despreading unit 22 extracts the transmission rate of received data from the transmission format parameter detected by the control channel despreading unit 21, and performs despreading processing on the data channel through which user data is transmitted.

  The demodulator 23 performs phase compensation and maximum ratio synthesis on the received despread data and stores it in the demodulated data memory 24. The received data stored in the demodulated data memory 24 is read out to the decoding unit 25 and decoded. In other words, the decoding unit 25 performs an error correction process corresponding to the encoding process applied on the transmission side, and performs a framing process for each data type after detecting a CRC (Cyclic Redundancy Check) based on a predetermined parameter, thereby performing a frame protocol processing unit 12 is output.

  The frame protocol processing unit 12 performs frame protocol processing necessary for interfacing with a wired transmission path. The data processed by the frame protocol processing unit 12 is converted into an ATM cell by the wired transmission path interface unit 11 and converted to an ATM cell, and sent to the host device (RNC) via the wired transmission path. Here, when an IP (Internet Protocol) transmission path is used instead of ATM as the wired transmission path, the wired transmission path interface unit is connected to the IP public network via a broadband gate way router (BGW). 11 has a function of terminating Ethernet (registered trademark) and IP (Internet Protocol).

  For the uplink common channel, the reception data stored in the reception memory 15 is input to the control channel despreading unit 31 and the data channel despreading unit 32 of the baseband receiving unit 30 of the common channel as in the case of the dedicated channel.

  The control channel despreading unit 31 generates a spreading code applied at the time of spreading modulation on the transmission side with respect to a control channel in which control information such as a transmission format for each channel is stored, and performs a despreading process on the received signal . Similarly to the control channel despreading unit 21 of the baseband receiving unit 20, the control channel despreading unit 31 calculates a phase rotation amount based on a known pilot pattern to be inserted, and performs detection and phase compensation of data symbols. Use.

  The data channel despreading unit 32 extracts the transmission rate of received data from the transmission format parameter detected by the control channel despreading unit 31 and performs despreading processing on the data channel through which user data is transmitted.

  The demodulator 33 performs phase compensation and maximum ratio synthesis on the received despread data and stores it in the demodulated data memory 34. The received data stored in the demodulated data memory 24 is subjected to error correction processing corresponding to the encoding processing applied on the transmission side in the decoding unit 25, and framing processing for each data type after CRC detection by a predetermined parameter. Output to the frame protocol processing unit 12.

  On the other hand, in the downlink signal, each channel received by the base station apparatus from the ATM line is assembled and disassembled by the wired transmission path interface unit 11 and input to the frame protocol processing unit 12. The frame protocol processing unit 12 performs conversion to the transmission channel format and adjustment of the transmission timing on the wireless transmission path according to the frame protocol, and then determines whether the received frame type is an individual channel or a common channel. In this case, the data is output to the encoding unit 41 that performs channel encoding processing of the baseband transmission unit 40 of the downlink dedicated channel. The data encoded by the encoding unit 41 is modulated by the modulation unit 42 by a digital modulation method such as QPSK to be applied, and sent to the spread processing unit 16.

  The spread processing unit 16 performs spread modulation processing on the data modulated by the modulation unit 42 using a predetermined spread code and outputs the result to the radio unit 14.

  If the frame protocol processing unit 12 determines that the processing data is a common channel, the data is sent to the baseband transmission unit 50 of the downlink common channel, encoded by the encoding unit 51, and encoded by the modulation unit 52. After being modulated, it is sent to the radio unit 14 via the spread processing unit 16.

Next, processing when the base station apparatus is installed, which is a feature of the present invention, will be described.
First, configuration required for operation is performed when the base station apparatus is started up. When starting up a base station device, it is necessary to measure the installation location environment in the wireless access system, that is, the installation status of other base station devices and radio wave propagation status. Different downlink common channel receivers 70 are activated to measure broadcast information and signal levels of neighboring base station apparatuses.

  The call control unit 131 sets parameters necessary for processing by the radio unit 14 and the baseband signal processing unit. In this embodiment, a CDMA-FDD (Frequency Division Duplex) system is assumed. In this method, since the frequencies of the upstream signal and downstream signal are different, a frequency opposite to that during normal operation is set.

Hereinafter, the processing operation during configuration will be described with reference to the processing flow shown in FIG.
First, the call control unit 131 executes a frequency scan for the radio unit 14 (step A1). That is, the carrier frequency of the frequency band assigned to the system is sequentially set, and RSSI (Received Signal Strength Indicator) that is the received signal strength is measured. This frequency scan makes it possible to search for frequencies that are actually used. During scanning, a threshold is set for RSSI, and all frequencies whose RSSI level is equal to or higher than the threshold are held as effective frequency numbers.

  Next, a cell search is performed on the detected frequency (step A2). In cell search, timing detection and scramble code detection are performed on a perch channel, which is a downlink common channel of the base station apparatus.

  In the CDMA system, there is a three-stage cell search method as a known technique. First, in the case of an asynchronous system between base station apparatuses, initial synchronization is necessary because the timing of a downlink signal that is base station transmission is unknown. For this initial synchronization, a synchronization channel (P-SCH: Primary Synchronization Channel) is applied, and a synchronization channel (SCH) that has been spread-modulated with a system-wide spreading code is received by the synchronization unit 71 of the downlink common channel receiving unit 70. The timing can be detected by despreading and performing correlation calculation.

  In general, a matched filter (MF) is used for the correlation calculation. At this detection timing, a scramble code group is further identified using a second synchronization channel (S-SCH). That is, the scramble codes applied to the cells are grouped into several types of codes, and different second synchronization channel patterns (S-SCH patterns) are applied to the groups. Since the association of the group with this scramble code is specified in advance, the scramble code candidates applied to the cell are limited by determining the group in the second synchronization channel (S-SCH). become. Further, since the second synchronization channel pattern (S-SCH pattern) is a pattern that also depends on the frame timing, it is possible to detect the frame timing of the base station apparatus to be detected.

  As a third step, a specific scramble code is identified from limited scramble code candidates.

  In addition, the reception level measurement for the base station apparatus detected by the cell search is also performed. As an assumption target, a constantly transmitted pilot channel (CPICH) is used to measure elements such as Ec / No (signal power to noise power ratio) that can determine signal quality. To determine whether it is a valid cell (step A3).

  Next, when there is a cell determined to be valid in the above procedure, broadcast information is transmitted for each cell by using the timing of the neighboring base station apparatus detected by the despreading unit 72 and the demodulating unit 73 and the scramble code. A broadcast channel (BCH) is received. This broadcast channel (BCH) includes the operation status of the base station device, parameters at the time of establishing a radio link, and neighboring cell information, and common information is constantly transmitted to terminal devices existing in the cell. Yes. The frequency number and the scramble code list in the peripheral cell information are demodulated by the demodulator 73 and stored in the demodulated data memory 74, and the broadcast channel (BCH) is decoded and acquired by the decoder 75.

  Repeat the above procedure for each effective cell at each frequency obtained by RSSI frequency scanning, measure all the observable cells, and use a table of neighboring cells that can be used near the installation location (peripheral Update the cell table.

  As described above, parameters to be considered in the environment where the base station apparatus is installed are extracted. That is, in the generated neighboring cell table, a frequency is arbitrarily selected from effective frequency numbers, and a scramble code not included in the set of cells having the selected frequency is arbitrarily extracted from the default table and applied as a scramble code of the own cell ( Step A4). As for frequency, when a carrier different from the surroundings is set, hard handover occurs when moving between cells, and depending on the cell accommodation channel state of the handover destination, forced disconnection occurs if it cannot be accommodated. From the viewpoint of the call loss rate, it is desirable to minimize the frequency of movement between cells having different frequencies. Therefore, any frequency applied to the neighboring cell is also applied at the start of operation of the base station apparatus (Cell Setup).

  On the other hand, if a valid cell is not detected, an arbitrary frequency and scramble code are selected from the default table (for example, using the sum value of the device unique number) (step A5).

  The default table stores carrier frequencies and scramble codes that are permitted to be used. The contents of the default table are not updated according to the operation status of the base station apparatus, but are pre-assigned depending on the corresponding wireless communication system and the provider providing the wireless communication service. And

  In the search for neighboring cells in step A2, if the detection of the downlink transmission frequency and scramble code of the neighboring base station of the wireless system corresponding to the base station cannot be detected at the place where the base station is to be installed, The process proceeds to step A5. In this case, it can be determined that the installation environment is an area where the wireless terminal cannot be used due to reasons such as being outside the service area or when the wireless propagation environment is extremely bad. That is, it can be seen that, in selecting base station information at the time of installation, it is not necessary to consider the influence of interference due to scramble code duplication with neighboring base station apparatuses and downlink transmission power. In addition, since it has a single cell configuration, there is no need for frequency selection in consideration of handover. Therefore, as the setting of the base station information of the base station apparatus, a carrier frequency and a scramble code within a range permitted to be used in advance are arbitrarily selected and set.

  Then, after determining the parameters to be applied at the time of starting the operation (Cell Setup), the applied scramble code and the frequency are notified to the host device (RNC) connected to the base station device (step A6). Thus, the Cell Setup process is performed (step A7). Normally, the host device (RNC) is connected to the base station device, and in addition to the exchange of C-Plane (inter-station control signal) and U-Plane (user data) required for call connection, the operation status of the base station device It has an interface for a maintenance monitoring function for the purpose of monitoring etc. The parameters applied at the start of operation (Cell Setup) are notified using this maintenance monitoring interface. When the terminal apparatus moves between cells, the host apparatus (RNC) takes over the call connection by soft handover or hard handover.

Here, the procedure of handover will be described.
The terminal device normally monitors the signal quality by periodically measuring the reception level of the downlink common channel in a call connection state between the base station devices. When the cell boundary is reached due to the movement of the terminal device, the downlink reception level measurement result of the other cell is notified to the host device (RNC) via the connected base station device, and other than the downlink quality of the connected cell. When it is determined that the downlink quality of the cell is good and the channel accommodation status of the cell that is the migration destination candidate can be accommodated, a handover is instructed by control from the base station apparatus of the migration source cell .

  Here, when the radio frequencies of the migration source cell and the migration destination cell are the same, a plurality of radio links are simultaneously transmitted from different cells, and the terminal device can receive the same downlink signal at almost the same timing. Thus, a soft handover state in which the timing offset is adjusted is obtained. In soft handover, a diversity effect by a plurality of uplink and downlink radio links can be expected. On the other hand, when the transfer destination and transfer source radio frequencies are different, it is necessary to switch the frequency of the radio unit, so a hard hand that instantaneously switches the frequency and the downlink scramble code applied to each cell based on a certain timing. Over is required.

  In order to realize these handover functions, as described above, it is necessary to control whether or not handover is possible from the host device (RNC), designation of the transfer destination, and the like, and it is under the control of a certain host device (RNC). It is essential to understand the operation parameters of the base station device. For the above reasons, in the above-described embodiment in which the operation parameters are determined autonomously at the start of operation (Cell Setup), a means for notifying the host device (RNC) is required.

Next, a transmission power control method for the downlink common channel of the radio base station apparatus will be described.
Usually, the transmission power of the downlink common channel of the radio base station apparatus is operated with a fixed value. That is, when the area covered by the base station apparatus is fixed at the time of zone design, it is necessary to set the reception apparatus to a level that provides sufficiently good signal quality as the reception level of the terminal apparatus located in the cell. If the transmission power is too low for the corresponding area, it can be easily assumed that the zone design conditions cannot be satisfied, but even if it is too large, it affects the communication quality in the neighboring cells as interference. In addition, since the terminal device selects the cell with the highest level in the cell list detected at the time of cell search and performs communication, the transmission level of the installed base station device is sufficiently low, and other If the cell level is sufficiently high, there is a possibility that only a cell of another base station apparatus is used even though the base station apparatus is installed.

  In order to avoid the above problems and set the power value at an appropriate level, in this embodiment, the downlink common channel receiver 70 measures the interference level (step A8), and the pilot channel based on the measurement result. The transmission power value of (CPICH) is determined (step A9). The interference level is measured by demodulating the downlink signal by a known method using the scramble code and frequency notified in step A6.

  As an application case of the base station apparatus in the present embodiment, it is assumed that it corresponds to a sufficiently narrow area, and assuming that the common channel transmission power is as low as several dBm, this default value of the pilot channel (CPICH) An offset value (according to the interference level) is added to the transmission power to realize a reliable area configuration with higher power than the level of the surrounding cells. All downlink transmission powers of other channels are determined using an offset value defined in advance with reference to the power value of the pilot channel (CPICH). Therefore, the transmission power adjustment according to the installation environment can be easily realized only for the pilot channel (CPICH). If the interference level is high and the transmission power is exceeded, the transmission power may be made sufficiently low, or the process may return to step A3 to select another frequency.

  Since the downlink common channel receiving unit 70 of the base station apparatus, which is a feature of the embodiment shown in FIG. 1, needs to be activated only when the base station apparatus is configured, for example, a DSP (Digital Signal Processor) is mainly used. As for the baseband signal processing unit implemented as follows, the file downloaded by the firmware can be switched between the initial configuration and the normal operation. The signal format of the physical channel level differs depending on whether it is upstream or downstream, but in the case of function unit units, the signal processing functions at the operation level such as spreading / despreading and encoding / decoding are often common. Therefore, it can be easily handled by a combination of modularized signal processing blocks.

  According to the above-described embodiment, when a small-scale zone configuration in which a user can freely install a base station device is configured, other peripheral base station devices based on a radio access method depending on a place where the radio base station device is installed. In order to obtain the installation status and radio wave propagation status, the baseband signal processing is switched to the processing for receiving the downlink signal of another base station device, and the radio information is measured by measuring the broadcast information and signal level of the neighboring base station devices. 14 and each baseband signal processing unit can be automatically set based on the measurement result, such as a spreading code and transmission power necessary for installing the base station apparatus. In addition, since the radio base station apparatus has an initial cell search function equivalent to that of the terminal apparatus, it can acquire peripheral base station information in the actual installation environment, and can independently set parameters specific to the base station apparatus suitable for the actual environment. Therefore, it is possible to cope with an environment where a booster is installed. Furthermore, since various parameters suitable for the actual environment can be set autonomously in the radio base station apparatus, it is only necessary to notify the host apparatus, and therefore, it can be carried out without imposing a burden on the host apparatus.

  In the above embodiment, the call control unit 131 may be configured to have an interface with a radio module equivalent to a terminal. That is, a wired interface function for a control signal with a modularized terminal device that communicates with a base station device is usually provided, communication protocol control is set for the terminal device, and wireless communication is required when the base station is installed In order to obtain the installation status and radio wave propagation status of other base station devices according to the access method, the downlink signal of the peripheral base station device is received using the above-mentioned modularized terminal device, and the broadcast information, signal level of the peripheral base station device is received. Measurement may be performed to automatically set the spreading code, transmission power, and the like necessary for installing the base station apparatus. In this case, as a connected module, a frequency scan function, a cell search function, a reception level measurement function, and a broadcast information reception function that are normally activated in the terminal device are applied. Only possible.

Next, the configuration of the receiving unit of this embodiment will be described.
FIG. 3 shows a configuration diagram of the receiving unit. A downlink reception signal received by the antenna 300 is input to a mixer 303 via an LNA (low noise amplifier) 301 and a band pass filter (BPF) 302. In the mixer 303, the signal is converted into an IF signal by mixing with the output of the RF local oscillator 304. The signal output from the mixer 303 via the band pass filter (BPF) 305 is detected by the detection unit 306 and is output to the baseband unit as an RSSI signal that is a reception level.

  On the other hand, the reception signal output from the bandpass filter 305 is digitally quadrature detected by the quadrature detection unit 307 using the output of the reception IF local oscillator 308, and a low pass filter (LPF) 309 as an I / Q signal with the base plate. The signal is output to the baseband signal processing unit via the AD converter (ADC) 310. In the baseband signal processing unit, the digital I / Q signal that is the output of the AD converter 310 is stored in the sample data memory 311, and the matched filter (MF) unit 312 performs correlation calculation with the spreading code. The matched filter (MF) unit 312 performs path detection by correlation calculation, obtains a received signal by performing synchronization detection and despread demodulation. Reference numeral 313 denotes a spreading code generation unit that generates a spreading code applied at the time of despreading.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying constituent elements without departing from the scope of the invention in the implementation stage.

It is a block diagram which shows the structure of the radio base station apparatus which concerns on one Embodiment of this invention. It is a flowchart which shows the processing operation at the time of configuration in the same embodiment. It is a block diagram which shows the structure of the receiving part in the embodiment. It is a block diagram which shows the structure of the conventional radio base station apparatus. It is a figure which shows the zone structural example in the conventional radio base station apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Wired transmission line interface (IF) part, 12 ... Frame protocol (FP) process part, 13, 131 ... Call control part, 14 ... Radio | wireless part, 15 ... Reception memory, 16 ... Spreading process part, 20 ... Baseband reception 21, control channel despreading unit 22, data channel despreading unit 23, demodulating unit 24, demodulated data memory 25, decoding unit 30, baseband receiving unit 31, control channel despreading unit 32 Data channel despreading unit 33 ... Demodulating unit 34 ... Demodulated data memory 35 ... Decoding unit 40 ... Baseband transmitting unit 41 ... Encoding unit 42 ... Modulating unit 50 ... Baseband transmitting unit 51 ... Encoding , 52 ... Modulator, 70 ... Downlink common channel receiver, 71 ... Synchronizer, 72 ... Despreader, 73 ... Demodulator, 74 ... Demodulated data memory, 75 ... Decoder , 300 ... Antenna, 301 ... LNA, 302 ... Band pass filter, 303 ... Mixer, 304 ... RF local oscillator, 305 ... Band pass filter, 306 ... Detection unit, 307 ... Quadrature detection unit, 308 ... IF local oscillator, 309 ... Low-pass filter, 310 ... AD converter, 311 ... Sample data memory, 312 ... Matched filter unit, 313 ... Spreading code generation unit

Claims (3)

A wireless unit that performs wireless communication with the mobile station;
A reception memory that stores reception spectrum spread data that is received by the radio unit and sequentially sampled in units of samples;
A baseband receiver for processing and decoding received data stored in the reception memory;
A downlink common channel receiver that is activated when the apparatus is started up and receives downlink signals of other base station apparatuses from the received data stored in the reception memory;
It has a wired transmission line interface to the host device, performs frame protocol processing for the interface with the wired transmission line, and transmits the upstream signal received by the baseband receiver and the downstream signal from the host device Frame protocol processing means for converting the channel format;
A baseband transmitter that encodes and digitally modulates and outputs downlink data output from the frame protocol processing means;
A spread processing unit that performs spread modulation processing on the data output from the baseband transmission unit and outputs the processed data to the radio unit;
A call control unit that controls allocation of processing resources of each functional unit when a new call is received in the base station device;
When the apparatus is started up, the downlink common channel receiving unit is activated to measure the broadcast information and signal level of the neighboring base station apparatus, and based on the measurement result, the spreading code and transmission power necessary for installing the own base station apparatus A wireless base station apparatus that automatically performs setting such as A wireless unit that performs wireless communication with a mobile station and other wireless base station devices;
A reception memory that stores reception spectrum spread data that is received by the radio unit and sequentially sampled in units of samples;
A baseband receiver for processing and decoding received data stored in the reception memory;
It has a wired transmission line interface to the host device, performs frame protocol processing for the interface with the wired transmission line, and transmits the upstream signal received by the baseband receiver and the downstream signal from the host device Frame protocol processing means for converting the channel format;
A baseband transmitter that encodes and digitally modulates and outputs downlink data output from the frame protocol processing means;
A spread processing unit that performs spread modulation processing on the data output from the baseband transmission unit and outputs the processed data to the radio unit;
A call control unit that controls allocation of processing resources of each functional unit when a new call is received in the base station device;
When the device starts up, at least part of the baseband signal processing is switched to processing for receiving downlink signals of other base station devices to search for neighboring base station devices, and when a valid cell is detected, the radio unit transmits The radio base station apparatus is characterized in that the frequency used for the cell is set to be the same as the frequency of the cell, and the spreading code used by the spreading processing unit is set differently from the spreading code of the cell. The radio base station apparatus according to claim 1,
Usually, it has a wired interface function for control signals with modularized terminal devices that communicate with the base station device, sets communication protocol control for the terminal device, and is necessary when installing the base station device. In order to obtain the installation status and radio wave propagation status of other base station devices by radio access method, the downlink signal of the peripheral base station device is received using a modularized terminal device, and the notification information and signal level of the peripheral base station device are received. A radio base station apparatus that performs measurement and automatically sets a spreading code, transmission power, and the like necessary for installing the base station apparatus.

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