JP5379052B2 - Terminal tester - Google Patents

Description

  The present invention relates to a terminal tester that receives an uplink radio data signal transmitted by a mobile communication terminal and performs timing synchronization.

  In recent years, with the increase in transmission amount by downloading music data or video data from a content server providing music and video to a mobile communication terminal via a base station, the mobile communication terminal has been developed by 3GPP, an international standardization organization. The W-CDMA system has been expanded as a wireless data communication system in the base station. This is known as High Speed Downlink Packed Access (HSDPA), which is a high-speed downlink in the downlink direction from the base station to the mobile communication terminal.

  Furthermore, with the increase in downlink download from the base station to the mobile communication terminal, the amount of transmission due to upload from the mobile communication terminal via the base station has increased. Therefore, in order to be able to transmit a large amount of data in a short time, HSDPA transmits a channel (HS-PDSCH) for transmitting actual data in a time division manner, but by multiplexing the channels at the same time. HSUPA (High Speed Uplink Access) that enables high-speed uplink from the terminal to the base station has been standardized.

  Patent Document 1 discloses a technique related to an uplink communication system and a terminal in a W-CDMA wireless communication system. Here, in HSDPA, which is a downlink in the downlink direction, a newly added downlink dedicated channel HS-PDSCH (for actual data transmission) is time-divided by the user, and DPDCH (Dedicated Physical Data Channel) is a channel for transmitting user information. And DPCCH (Dedicated Physical Control Channel), which is a channel for transmitting control information, to the terminal.

  In HSUPA with increased uplink speed, a signal including DPDCH and DPCCH is transmitted to the base station. The HSUPA received signal received by the base station has a different channel depending on the information element. For example, the signal at the time of HSUPA reception includes DPCCH that is W-CDMA control information, DPDCH that is W-CDMA actual data, E-DPCCH that is HSUPA control information, and E-DPDCH that is HSUPA actual data. Have. In addition, since a signal at the time of HSUPA reception is obtained by combining a plurality of signals after code spreading, it is necessary to perform despreading in order to extract each channel. With the progress of such wireless data communication, a terminal communication tester used for development, repair, and maintenance of a mobile communication terminal (hereinafter referred to as “User Equipment”) is also required to have a similar communication function.

JP 2008-72194 A

  FIG. 4 is a diagram showing a difference between transmission power and power per channel in W-CDMA and conventional W-CDMA + HSUPA detection. FIG. 4A shows an overview of the conventional version of the transmission power of the W-CDMA system and the W-CDMA + HSUPA system, which is an extension of the W-CDMA system. In the W-CDMA system, it is a combined signal of 2 channels of DPCCH and DPDCH, whereas in the W-CDMA + HSUPA system, it is a combined signal of 4 channels of DPCCH, DPDCH, E-DPCCH, and E-DPDCH. However, although there is a difference in the number of channels in the W-CDMA system and the conventional version of the W-CDMA + HSUPA system, it is necessary to reduce the power of each channel in order to suppress the transmission power transmitted by the terminal to the same level. As shown in FIG. 4B, the transmission power of the W-CDMA + HSUPA scheme is smaller than that of the W-CDMA scheme.

  In the W-CDMA + HSUPA system, when the above-described multiplexing combination is changed, the necessary energy-to-noise ratio per channel is controlled to maintain communication quality, and the transmission power of the channel is made variable according to the multiplicity of the channel. There is a need. For this reason, a specification for changing the power ratio between the channels is defined in the conformance test of the 3GPP standard. The amount of change in the power ratio between the channels is 1/15 steps from 0 to 15/15, and the power ratio of each channel can be a large value of about 24 dB at the maximum. Here, the power ratio between channels dynamically changes depending on the amount of data to be transmitted (for example, an improved version of FIG. 4A), and a channel with a relatively large power ratio is easier to detect correctly. In actual communication, channels that have a large power ratio and are easy to detect are dynamically changed. Therefore, in the HSUPA method, it is necessary to correlate all channels, and the load of correlation processing also increases.

  In particular, in a terminal tester, not only communication but also an application program related to measurement is important. In general, the terminal tester often realizes functional improvements by updating software, and is configured by dedicated radio hardware, DSP for signal processing, and general-purpose CPU software. For this reason, the increase in correlation processing in the uplink radio packet also increases the load on the terminal tester.

  FIG. 5 shows an example relating to the difference in detection processing time between the W-CDMA system and the W-CDMA + HSUPA system by the terminal tester. In the W-CDMA system, processing ends within one frame (10 ms) of W-CDMA, but in the W-CDMA + HDUPA system, processing does not end within one frame and processing delay occurs. Therefore, in order to improve performance based on limited hardware resources, the terminal tester optimizes software processing through repeated trial and error so that processing is completed within one frame of W-CDMA. . However, performance improvement by such optimization increases costs in software development.

  Therefore, in the terminal tester according to the present invention, in order to reduce the number of channels to be processed by the terminal tester in the process of acquiring the timing synchronization of the uplink radio packet, the reception timing is detected in a channel that is easy to detect by instructing the terminal in advance. Accordingly, an object of the present invention is to provide a terminal tester that can reduce the burden of correlation processing.

  In order to achieve the above object, the terminal tester according to the present invention performs an uplink transmission from a mobile communication terminal in order to synchronize so that it can be received at a correct signal timing in order to obtain necessary information such as a packet. In a terminal tester that receives a wireless data signal and performs timing synchronization, the terminal tester transmits, to the mobile communication terminal, the transmission power of a predetermined channel among other channels included in the uplink wireless data signal. Power setting means for setting to be larger than the channel, channel selection means for selecting in order of the channel having the highest transmission power among the plurality of channels included in the received uplink radio data signal, and correlation processing of the selected channel, respectively A correlation means for performing the search, and a search means for searching for the timing of the peak value after adding the correlation results of the obtained channels. And, and it performs timing synchronization of the uplink radio data signal based on the timing of the searched peak value.

  Specifically, as shown in the improved version of FIG. 4, although the transmission power is smaller than that of the W-DCMA system, the accuracy of the correlation processing peak value detection is improved by increasing the transmission power by a predetermined channel compared to the conventional version. Plan. In addition, although four channels are used in the uplink in the uplink radio data signal obtained by extending the W-CDMA scheme, by setting transmission power large for only two channels for the mobile communication terminal before timing synchronization, It is possible to reduce 4-channel correlation processing to 2-channel correlation processing.

  In the terminal tester according to another preferred invention, the power setting means sets the transmission power of the predetermined channel to be higher than that of the other channels, with an upper limit of half of the plurality of channels included in the uplink radio data signal. It is characterized by doing.

  Here, the reason why the number of channels is two, which is half of all channels, is to secure data necessary for the addition processing for more accurately detecting the peak value of the correlation function. Therefore, even if the standard is changed in the future and becomes 8 channels or more, processing can be suitably performed if at least two correlation function peak values are obtained with the upper limit of half (4 channels).

  By using the terminal tester according to the present invention, there is an effect that it is possible to reduce the load of correlation processing necessary for timing synchronization for the uplink radio data signal.

It is the block diagram which showed the layer structure of the terminal tester which concerns on this embodiment. It is a flowchart figure which shows the whole flow of the timing synchronous detection process processed in the de-spreading / demodulation part of FIG. FIG. 3 is a flowchart showing a specific processing flow in the synchronization detection processing of FIG. 2. It is explanatory drawing explaining the HSUPA detection of the conventional version, and the HSUPA detection of an improved version. It is explanatory drawing explaining the problem in the HSUPA detection processing time of the conventional version. It is a flowchart figure which shows the flow of the synchronous detection process used as a reference in understanding this embodiment.

  Hereinafter, the best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described with reference to the drawings.

(Layer structure of terminal tester)
FIG. 1 shows a layer configuration of hardware and software of the terminal tester 1. The terminal tester 1 is composed of a communication device, a dedicated DSP, and an upper-layer general-purpose CPU from the lower layer in order to perform wireless communication with the terminal 2, and functions as a terminal tester by processing of each layer.

  The communication device includes a transmitter and a receiver, and includes an antenna 10, a wireless communication circuit 11, a D / A conversion unit 13, and an A / D conversion unit 12, and realizes transmission / reception using digital signals. The dedicated DSP located in the upper layer of the communication device has a coding unit 24, a spreading / modulating unit 23, a decoding unit 22 and a despreading / demodulating unit 21 that synchronize the uplink. doing.

  A general-purpose CPU located in a layer above the dedicated DSP has a layer 2 for executing primary processing such as packet data processed by the layer 1, and a layer 3 for executing input / output of packet data and control information. Have. The voice 14 can be extracted from the input / output of the layer 1, and the control information 15 stores the measurement information to be set and measured by the terminal tester 1, and the synchronization of the despreading / demodulating unit 21 of the layer 1 depending on the situation The detection method and the like can be changed.

  Next, the function of each layer will be described. The communicator is responsible for transmission / reception of radio waves and conversion to digital data, the dedicated DSP is responsible for despreading / demodulation and spreading / modulation for transmission / reception, and the general-purpose CPU delivers digital data, inputs various setting values, and performs various measurements. Responsible for processing.

  With this configuration, the terminal tester 1 can act as a base station for the terminal 2 and measures a signal immediately after demodulation / despreading / decoding in a wireless data signal transmitted from the terminal tester 2 to the terminal 1. be able to.

  Generally, the terminal 2 is not in a state in which a wireless performance test is possible only by turning on the power. Therefore, the terminal 2 requests the terminal tester 1 functioning as a base station for necessary registration settings (registration) through digital control information of radio waves, and after the terminal tester 1 performs registration, the terminal tester 1 The terminal 2 is switched to a testable state (test mode), and the use channel to be described later is set.

  FIG. 2 shows the overall flow of the timing synchronization detection process using the correlation process processed by the despreading / demodulating unit 21 of FIG. The processing shown in FIG. 2 can be divided into three types: initial setting, synchronization detection, and reception synchronization maintenance. In W-CDMA, since each channel is assigned with a different spreading code, it is necessary to obtain a spreading code of a channel that is desired to be received by timing synchronization or despreading. Correlation is performed with data for L chips, which is a unit of the number of data, and correlation processing is performed by shifting to a predetermined position while shifting the data start position by one chip.

  In the initialization setting of FIG. 2, the memory space of the correlation length and the correlation range is initialized by the initialization in step S10, and the spreading code of each channel to be received is set by the parameter setting in step S12. Next, in the synchronization detection process of FIG. 2, the data for each frame is acquired in step S14, the process necessary for timing synchronization is detected in step S16, and the timing synchronization position is based on the detected correlation value for each position. Is detected. If the timing synchronization cannot be achieved in step S18 and the reception position detection fails, the process returns to step S14.

  When the reception position can be detected, in order to keep the detected timing synchronization, data on the next frame is acquired in step S20, reception synchronization is performed in step S22, and the obtained correlation value is used in step S24. Synchronization maintenance confirmation is performed, and synchronization maintenance processing is continued in step S26. If the synchronization is lost in step S26, the process returns to step S14.

(First embodiment)
FIG. 3 shows a specific flow of processing in the synchronization detection processing of FIG. One of the characteristic matters in the present embodiment is that the amount of calculation is reduced by selecting two from the higher received power values based on the transmission power value defined by the 3GPP standard or the user setting. In addition, the calculation processing time is shortened. Specifically, first, the terminal tester 1 is provided with means for setting a transmission power value, the specified value from the setting means is stored in the control information 15, and the transmission power value read from the control information 15 is transmitted to the terminal. At the same time as transmitting, the transmission power value designated by the layer 3 DSP in FIG. 1 is notified to the lower layer DSP to perform timing synchronization. Second, the peak value detection accuracy is improved by adding two correlation results obtained by the correlation processing.

  When the synchronization detection process in FIG. 3 starts, the despreading / demodulating unit 21 in FIG. 1 takes in data for each frame number in step S30. Next, in step S32, it is set that there are two priority channels from the power value for each channel set by the upper layer. Next, in step S34, a determination value for peak value search to be described later is obtained from the designated power value. This determination value calculation is to prevent erroneous detection of channels other than the priority channel.

  In step S36, the first correlation process is despread with a despread code. Next, in step S38, the second correlation process is despread with another despread code. Next, the first and second correlation results are added in step S40, and a peak value search is performed on the data added in step S42.

  In step S44, when the peak value is smaller than the determination value, the peak value and the chip position are stored as “peak detected” only when the determination value is exceeded, so that the peak value is smaller than the determination value. Then, the peak value and the chip position are stored as “peak non-detection”. This completes the synchronization detection. This processing makes it possible to execute timing synchronization with a minimum amount of calculation.

(Reference example)
FIG. 6 shows a synchronization detection process for W-CDMA + HSUPA detection, which is helpful in understanding this embodiment. This embodiment is a basic form in which timing synchronization is performed by executing correlation processing of each of four channels. When the synchronization detection process of FIG. 6 starts, in step S50, the despreading / demodulation unit 21 of FIG. 1 takes in data for each frame number. Next, in step S52, correlation processing for four channels is executed to obtain a peak value and a chip position, respectively. Next, iterates until all four channels are searched in step S56. In step S58, the peak value is determined as “peak detected” only when the highest peak value of all four channels exceeds the judgment value. The chip position is stored, and the peak value and the chip position are stored as “no peak detected” below the determination value. This completes the synchronization detection.

  In the present embodiment shown in FIG. 3, the embodiment in which a terminal tester with a low DSP processing capability is used has been described. However, the correlation processing for all four channels shown in FIG. In the case of using a DSP having a high processing capacity such as ending in FIG. 4, it is also preferable to switch between the processing of FIG. 4 and the processing of FIG.

  As described above, by using the terminal tester according to the present embodiment, it is possible to reduce the load of correlation processing necessary for timing synchronization for the uplink radio data signal, and to reduce the cost for software development and the terminal tester. It is also possible to use inexpensive hardware.

  1 terminal tester, 2 terminals, 10 antenna, 11 wireless communication circuit, 12 A / D conversion unit, 13 D / A conversion unit, 14 voice, 15 control information, 16 packet data, 20 layers 1, 21 despreading / demodulation unit , 22 decoding unit, 23 spreading / modulating unit, 24 encoding unit, 30 layer 2, 40 layer 3.

Claims (2)

In a terminal tester that receives uplink radio data signals transmitted by mobile communication terminals and performs timing synchronization,
The terminal tester
A power setting means for setting a transmission power of a predetermined channel among a plurality of channels included in an uplink radio data signal to be larger than that of other channels for a mobile communication terminal;
Channel selection means for selecting in order of the channel having the largest transmission power among the plurality of channels included in the received uplink radio data signal;
Correlation means for performing correlation processing for each selected channel;
After adding the correlation results of the obtained channels, search means for searching for the timing of the peak value,
And a terminal tester that performs timing synchronization of the uplink radio data signal based on the timing of the searched peak value. The terminal tester according to claim 1,
The power setting means
A terminal tester characterized in that transmission power of a predetermined channel is set to be larger than that of other channels, with the upper limit being half of the plurality of channels included in the uplink radio data signal.

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