JP5216036B2 - Base station evaluation apparatus and signal extraction method thereof - Google Patents

Description

  The present invention relates to a technique for analyzing and evaluating a signal output from a base station apparatus of a mobile communication system such as a mobile phone, and in particular, a multi-carrier system that performs simultaneous communication in a plurality of different frequency bands or a plurality of different ones. The present invention relates to a technique for enabling efficient evaluation of a base station apparatus compatible with a multi-standard method corresponding to a communication standard.

  In a mobile communication system such as a mobile phone, communication is performed by time-division multiplexing a plurality of user signals in a frequency band (carrier frequency) for communication between a base station and a terminal, but the number of users is large. Then, it becomes impossible to multiplex with one carrier frequency. For this reason, one communication company has increased the number of available users by using a plurality of carrier frequencies.

  Correspondingly, a so-called multi-carrier method is adopted in which the base station also performs communication simultaneously using a plurality of carrier frequencies.

  In addition, with the shift of the modulation method of terminals, etc., it is also required that one communication carrier communicates with different communication standards (for example, GSM and W-CDMA), and there are a plurality of base stations to cope with this. A so-called multi-standard method is employed in which signals are transmitted simultaneously using signals of different communication standards. In recent years, a base station apparatus compatible with multi-carrier and multi-standard is required.

  Therefore, a wireless standard for operating a plurality of systems in the same frequency band is defined as Multi-Standard Radio (MSR) Base Station (BS) in 3GPP TS 37.104. The frequency band is as shown in FIG.

  In FIG. 9, if an example of a multi-standard is given, MSR and E-UTRA (LTE) are used in, for example, frequency bands of 869 to 894 MHz and 925 to 960 MHz among frequency bands defined by the output (Downlink) of the base station. And three different systems are used: UTRA (W-CDMA) and GSM / EDGE.

  Therefore, in order to evaluate the base station apparatus that uses the carrier frequencies in the frequency bands of 869 to 894 MHz and 925 to 960 MHz for communication, it is necessary to measure each carrier frequency signal according to a different system. However, the conventional evaluation apparatus for mobile communication devices, for example, as described in the following Patent Document 1, selectively receives a signal of one carrier frequency (single carrier) and performs processing necessary for the evaluation. Therefore, when performing multicarrier measurement, a series of tests necessary for evaluation of one carrier frequency is performed, and then the next carrier frequency is transferred to perform the same test. There is a problem that it takes time and labor.

  In addition, due to the measurement principle, there is a problem that it is impossible to grasp the mutual influence between bands when a plurality of carrier frequencies are used simultaneously.

JP 2007-19741 A

  As a technique for solving the above problem, signal components of a plurality of carrier frequencies to be measured are collectively received by a heterodyne wideband receiver and converted into an intermediate frequency band, and the waveform of the signal in the intermediate frequency band A method is conceivable in which data is acquired and stored for a certain period of time, and signal components of individual carrier frequencies are extracted from the stored waveform data and analyzed.

  However, when actually configuring the evaluation device of the above method, if the measurement conditions can be arbitrarily set for each of a plurality of carrier frequencies to be measured and each frequency component, each signal component in the intermediate frequency band of the receiving unit It is necessary to have a technology for efficiently and reliably extracting

  The present invention solves this problem, and evaluates each signal component in the intermediate frequency band according to the set carrier frequency and measurement conditions in an apparatus for evaluating a base station apparatus compatible with multi-carrier and multi-standard. It is an object of the present invention to provide a base station evaluation apparatus and a signal extraction method thereof that can be reliably and reliably extracted.

In order to achieve the above object, a base station evaluation apparatus according to claim 1 of the present invention comprises:
Wideband reception that receives a signal including a plurality of different carrier frequencies used for communication by the base station apparatus to be evaluated, mixes the signal with a local signal, and converts the signal into an intermediate frequency band that covers the plurality of different carrier frequencies Section (22), an A / D converter (23) for sampling the signal output from the broadband receiving section and converting it into digital waveform data, and waveform data for storing the waveform data converted by the A / D converter A reception storage unit (21) having a memory (24) and acquiring waveform data of a signal output by the base station device at a predetermined time;
Analyzes the waveform data stored in the reception storage unit, detects a signal inserted in a desired time slot in the frame of each carrier frequency, and uses a modulation scheme and measurement items set in advance for the slot. An analysis unit (25) for performing signal demodulation and measurement based on the
A base station evaluation apparatus comprising: a setting unit (30) configured to set modulation method information and measurement item information for each carrier frequency and each slot in a frame for each carrier frequency to the analysis unit;
The analysis unit
The waveform data stored in the reception storage unit is read, and the read waveform data is subjected to frequency conversion processing using local signals of frequencies corresponding to the signal components of the plurality of carrier frequencies, and the plurality of carrier frequencies Each having a signal extraction means (26) for converting each signal component into a baseband,
An analysis process set for each signal component converted into a baseband by the signal extraction means is performed.

Further, the signal extraction method of the base station evaluation apparatus of the present invention is:
Wideband reception that receives a signal including a plurality of different carrier frequencies used for communication by the base station apparatus to be evaluated, mixes the signal with a local signal, and converts the signal into an intermediate frequency band that covers the plurality of different carrier frequencies Section (22), an A / D converter (23) for sampling the signal output from the broadband receiving section and converting it into digital waveform data, and waveform data for storing the waveform data converted by the A / D converter A reception storage unit (21) having a memory (24) and acquiring waveform data of a signal output by the base station device at a predetermined time;
Analyzes the waveform data stored in the reception storage unit, detects a signal inserted in a desired time slot in the frame of each carrier frequency, and uses a modulation scheme and measurement items set in advance for the slot. An analysis unit (25) for performing signal demodulation and measurement based on the
Signals in the analysis unit of the base station evaluation apparatus comprising: a setting unit (30) for setting the modulation method information and measurement item information for each carrier frequency and each slot in the frame for each carrier frequency to the analysis unit An extraction method comprising:
The waveform data stored in the reception storage unit is read, and the read waveform data is subjected to frequency conversion processing using a local signal having a frequency corresponding to one of the signal components of the plurality of carrier frequencies, The process of converting one of the signal components of the carrier frequency to the baseband is repeatedly performed for each signal component of the plurality of carrier frequencies,
An analysis process set for each signal component converted into the baseband is performed.

  As described above, according to the present invention, each signal component in the intermediate frequency band is sequentially converted into the baseband band according to the set carrier frequency and measurement conditions. Can be extracted.

Configuration diagram of an embodiment of the present invention The figure for demonstrating the operation | movement of the principal part of embodiment. The figure which shows the structure of the principal part of embodiment. The flowchart for demonstrating the operation | movement of the principal part of embodiment. The figure for demonstrating the operation | movement of the principal part of embodiment. The figure for demonstrating the operation | movement of the principal part of embodiment. The flowchart for demonstrating the operation | movement of the principal part of embodiment. The figure for demonstrating the operation | movement of the principal part of embodiment. The figure showing the relationship between the frequency band which a base station apparatus uses, and the system used for communication

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows the configuration of a base station evaluation apparatus 20 to which the present invention is applied.

  In FIG. 1, the reception storage unit 21 includes a broadband reception unit 22, an A / D converter 23, and a waveform data memory 24.

  The wideband receiving unit 22 has a wide reception band including a plurality of different carrier frequencies used for communication by the evaluation target base station apparatus 1 corresponding to multicarrier and multistandard (for example, 869 to 894 MHz, 925 to 960 MHz as described above). Frequency band), and the signal components of a plurality of carrier frequencies designated by the setting unit 30 described later are collectively received among the signals in the reception band.

Broadband receiving unit 22 includes a mixer 22a, includes a local signal generator 22b and the intermediate frequency filter 22c, and a local signal _{S LOC} output from the input signal _{S IN} and the local signal generator 22b to mix fed to the mixer 22a, One of the sum and difference components (here, the difference component) is extracted by the intermediate frequency filter 22c, and the band of the intermediate frequency filter 22c may be designated as a measurement target. It has a width W necessary to pass all the signal components of the carrier frequency.

  For example, when there is a possibility that the entire reception band of 925 to 960 MHz may be designated as a measurement target, a width of at least 960-925 = 35 MHz is required.

The frequency _{f LOC} of the local signal _{S LOC,} if the passing center frequency of the intermediate frequency filter 22c and _{f IF,} actually all _{f IF} ± signal components of the carrier frequency specified as the measurement object by setting section 30 Any value can be used as long as it is heterodyne converted into the intermediate frequency band of W / 2. | (925 + 960) / 2−f so that the signal components of the entire reception band of 925 to 960 MHz can be collectively converted into the intermediate frequency band. _{If LOC} | = f _IF , any carrier frequency within the reception band can be specified with a fixed local frequency f _LOC . Taking numerical examples, f _IF = 200 MHz and f _LOC = 742.5 MHz (or 1142.5 MHz).

  However, the carrier frequency (channel) to be measured is an item that is arbitrarily specified by the measurer. If the specified carrier is concentrated only on one end of the reception band, the frequency component of the signal component is converted to the intermediate frequency. This is concentrated on the edge of the pass band of the filter 22c, which is susceptible to the characteristics of the filter edge (amplitude and phase fluctuations) and is undesirable.

  In order to prevent this, it is possible to set the local frequency based on the carrier frequency specified by the measurer, but in addition to the above-mentioned carrier frequency, in addition to the slot designation and measurement item designation operation, If a local frequency setting operation is added, the operation becomes very complicated.

Therefore, in this base station evaluation apparatus 20, the reception frequency control means 50 automatically sets the frequency f _LOC (that is, the reception frequency) of the local signal output from the local signal generator 22b.

The reception frequency control means 50 obtains a minimum frequency range f1 to f2 necessary for measurement based on each carrier frequency set by the setting unit 30 and measurement item information, and a center frequency (f1 + f2) / f of the frequency range. The frequency f _{LOC of the} local signal is set so that 2 is converted to the passing center frequency f _IF in the intermediate frequency band.

That is, for easy understanding, if the lower heterodyne having a local frequency lower than the input signal frequency is used, the lower limit frequency f1 and the upper limit frequency f2 are determined according to the upper and lower limits of the carrier frequency arbitrarily specified by the measurer and the measurement item. Whereas
f _LOC = (f1 + f2) / 2−f _IF
Is obtained, and the frequency information is set in the local signal generator 22b to generate a local signal having the frequency f _LOC . For upper heterodyne,
f _LOC = (f1 + f2) / 2 + f _IF
Find and set the local frequency at which

  The lower limit frequency f1 and the upper limit frequency f2 are determined in consideration of the case where the measurement item of adjacent channel leakage is specified for the lower limit and the upper limit carrier frequency.

  As a result, for example, as shown in FIG. 2A, even when the carrier frequencies fc1 to fcn to be measured are biased toward the low frequency side of the entire reception band, the intermediate frequency as shown in FIG. The signals are gathered and output in the vicinity of the center of the band, and are not easily affected by fluctuations in the amplitude characteristics and phase characteristics of the filter edges. FIG. 2 shows the case of the lower heterodyne. However, in the case of the upper heterodyne, the arrangement of the signal components converted to the intermediate frequency band is inverted with respect to the case of FIG.

The signal S _IF converted to the intermediate frequency band is sampled by the A / D converter 23 at a predetermined frequency (more than twice the upper limit frequency of the intermediate frequency band), converted into a digital signal sequence D (k), and a waveform. It is stored in the data memory 24 for a certain time.

  The analysis unit 25 includes a signal extraction unit 26, a frame synchronization unit 27, and an analysis unit 28. The analysis unit 25 analyzes the waveform data stored in the waveform data memory 24 of the reception storage unit 21, and determines the signal component of each carrier frequency. Each baseband band is converted and extracted, and the extracted baseband component is subjected to frame synchronization processing, etc., the signal inserted in the desired time slot is detected, and the slot is preset. Signal demodulation and measurement are performed based on the modulation method and measurement items, and the results are displayed on the display unit 40.

  The signal extraction unit 26 reads the waveform data stored in the reception storage unit 21, performs a frequency conversion process on the read waveform data using local signals having frequencies corresponding to signal components of a plurality of carrier frequencies, Each signal component of a plurality of carrier frequencies is converted into a baseband. This frequency conversion processing is performed using quadrature detection processing in order to obtain two quadrature baseband components. However, as will be described later, when the quadrature component is detected in advance in the reception storage unit 21, the signal extraction means 26 is simple. It can be composed of a simple single-phase frequency converter.

For example, as shown in FIG. 3, the signal extraction means 26 includes two sets of mixers (multipliers) 26a and 26b, a local signal generator 26c, a 90-degree phase shifter 26d, baseband filters 26e and 26f, and a baseband signal. The memory 26g and the local frequency switching means 26h are configured, and the local signals L ₀ and L ₉₀ having the frequency f _LL generated by the local signal generator 26c and the 90-degree phase shifter 26d are supplied to the mixers 26a and 26b. baseband filter 26e from the mixer output, converts the signal component having a center frequency _{f LL} signal Ii baseband (e.g. 0～6MHz), to Qi through 26f, and stores it in baseband signal memory 26g . Further, the local frequency control unit 26h is configured to output a local signal to be output by the local signal generator 26c based on each carrier frequency to be measured designated by the setting unit 30 described later and the frequency of the local signal _{SLOC in} the reception storage unit 21. The frequency f _LL of the signal L ₀ is sequentially changed (note that the signal handled by the signal extraction means 26 is a digital data string, so the mixers 26a and 26b, the local signal generator 26c, the 90-degree phase shifter 26d, and the baseband Each component such as the filters 26e and 26f is realized by an arithmetic process equivalent to its function).

  The baseband components Ii and Qi for each carrier converted into the baseband band by the signal extraction means 26 are read for each carrier by the frame synchronization means 27, the specification of the head position of the frame is specified, and sent to the analysis means 28. It is done.

  The analysis unit 28 detects a signal inserted in a desired time slot of the frame, performs signal demodulation and measurement based on a modulation scheme and measurement items set in advance for the slot, and displays the result on the display unit 40. To display.

  The setting unit 30 displays the information necessary for setting on the display unit 40 in accordance with the operation of the operation unit 45, and causes the analysis unit 25 to display modulation scheme information and measurement items for each slot in each carrier frequency frame. This is for setting information.

  The information to be specified here is a measurement item such as a carrier frequency, a frame and slot of a signal component of the carrier frequency, a modulation method such as GMSK or 8PSK, and Power, Modulation (modulation error), ORFS (adjacent channel leakage), etc. The demodulation processing based on the designated modulation method is performed on the desired slot of the desired frame of the signal component of the designated carrier frequency, and the designated item is measured for the result.

  The analysis unit 25 refers to the information specified by the setting unit 30, and converts the signal components of the carrier frequencies fc1, fc2,... (Actually converted to the intermediate frequency band from the waveform data stored in the waveform data memory 24). Baseband components (I 1, Q 1), (I 2, Q 2),..., And signals inserted in desired time slots in the signal frame of each carrier frequency are detected, and the slots The signal demodulation process and various measurement processes are performed on the basis of the modulation method and measurement items specified for, and the results are displayed on the display unit 40.

  In addition, the reception frequency control means 50 described above determines the carrier frequencies fc1, fc2,... Specified by the setting unit 30, the modulation scheme (specifies the occupied bandwidth), and the presence / absence of adjacent channel leakage. Determine the reception frequency.

  FIG. 4 is a flowchart showing a processing procedure of the reception frequency control means 50. The reception frequency control process of the embodiment will be described below based on this flowchart.

  First, it is checked whether there is an adjacent channel leakage (ORFS or ACLR) item in the measurement item of the highest frequency among the carrier frequencies (channels) designated as the measurement object by the setting unit 30 (S1).

  When there is an adjacent channel leakage item, as shown in FIG. 5A, the upper limit frequency f2 ′ required for the measurement of the highest carrier frequency is set to the frequency width Wa required for the adjacent channel leakage measurement and a predetermined value. The upper limit frequency f2 is determined by adding the margin α (S2). If there is no adjacent channel leakage item, as shown in FIG. 5B, a predetermined margin β is added to the upper limit frequency f2 ′ required for the measurement of the highest carrier frequency to add an upper limit frequency. Let it be f2 (S3).

  Next, it is checked whether there is an adjacent channel leakage (ACLR or ORFS) item in the measurement item of the lowest frequency among the carrier frequencies (channels) designated as the measurement object by the setting unit 30 (S4).

  If there is an item of adjacent channel leakage, as shown in FIG. 6A, the frequency width Wa required for measurement of adjacent channel leakage from the lower limit frequency f1 ′ required for measurement of the minimum frequency of the carrier frequency. Then, the lower limit frequency f1 is determined by subtracting the sum of the predetermined margin α (S5). If there is no adjacent channel leakage item, as shown in FIG. 6B, a predetermined margin β is subtracted from the lower limit frequency f1 ′ necessary for measurement of the lowest carrier frequency to obtain the lower limit frequency f1. (S6).

Then, the center value fm = (f1 + f2) of the lower limit frequency f1 and an upper frequency limit f2 / 2 The calculated (S7), the local frequency _{f LOC} for the center value fm is converted to central pass frequency _{f IF} of the intermediate frequency band _Is calculated by f _LOC = fm−f _IF (or f _LOC = fm + f _IF ), and the frequency information is set in the local signal generator 22b (S8).

  As a result of the above processing, the waveform data memory 24 converts the signal including the signal component of the carrier frequency specified as the measurement target into the intermediate frequency band, and stores the waveform data of the signal for a predetermined time in the waveform data memory 24. .

  The waveform data stored in the waveform data memory 24 is subjected to signal extraction processing by the analysis unit 25 at a predetermined timing.

That is, assuming that the frequency of the carrier signal to be measured is fc1 to fcn and the lower heterodyne is used in the reception storage unit 21, each carrier frequency fc1 to fcn is a frequency (fc1−f) in the intermediate frequency band. _LOC ) to (fcn-f _LOC ).

Therefore, in the signal extraction process by the signal extraction means 26, as shown in FIG. 7, the variable i designating the carrier is initialized to 1 (S11), and the frequencies f _LL of the local signals L ₀ and L ₉₀ are set to (fci−f). _LOC ) is set (S12), and quadrature detection processing is performed on the waveform data stored in the waveform data memory 24.

As a result, as shown in FIG. 8A, the signal component centered on the intermediate frequency band frequency (fci−f _LOC ) is centered on the frequency 0 as shown in FIGS. 8B and 8C. Are converted into baseband components Ii and Qi, and the orthogonal baseband components Ii and Qi are stored at addresses corresponding to the corresponding variable i (S13).

  Then, the processes of S12 and S13 are repeated for the carrier frequency to be measured (S14 and S15), the baseband components (I1, Q1) to (In, Qn) for each carrier are obtained, and the frame synchronization process and Analysis processing is performed to obtain a desired measurement result, and the measurement result is displayed.

Thus, in the base station evaluation apparatus 20 of the embodiment, based on the measurement items for the carrier frequency set by the setting unit 30 and the measurement target time slot in the frame,
Since each signal component converted to the intermediate frequency band of the reception storage unit 21 is sequentially converted to the baseband, the signal component of each carrier can be extracted efficiently and reliably.

  In the above embodiment, the reception storage unit 21 controls the reception frequency so that the center of the upper limit frequency and the lower limit frequency necessary for measurement coincides with the pass center frequency of the intermediate frequency band. The baseband component of each carrier described above can be extracted if the intermediate frequency band is between the upper limit frequency and the lower limit frequency necessary for measurement.

Further, in the above embodiment, the quadrature detection processing is used in the signal extraction means 26 in order to convert the signal component of each carrier into quadrature baseband, but the quadrature two-phase type frequency conversion processing is performed in the reception storage unit 21. The received signal may be converted into orthogonal components I _IF and Q _IF in the intermediate frequency band and stored in the waveform data memory 24. In this case, the signal extraction unit 26 stores the waveform in the waveform data memory 24. Read out the quadrature components I _IF and Q _IF , respectively, to make the signal input of each of the single-phase type frequency converters (for example, the mixers 26a and 26b in FIG. 3 independent), and to provide both mixers 26a and 26b with in-phase local signals The local frequency of the frequency converter is sequentially changed according to each carrier, and the signal component of each carrier is centered on the frequency 0. Baseband component (I1, Q1) ~ (In, Qn) may be sequentially converted to.

  DESCRIPTION OF SYMBOLS 20 ... Base station evaluation apparatus, 21 ... Reception storage part, 22 ... Broadband receiving part, 22a ... Mixer, 22b ... Local signal generator, 22c ... Intermediate frequency filter, 23 ... A / D converter , 24 …… Waveform data memory, 25 …… Analysis unit, 26 …… Signal extraction unit, 27 …… Frame synchronization unit, 28 …… Analysis unit, 30 …… Setting unit, 40 …… Display unit, 45 …… Operation 50, reception frequency control means

Claims (2)

Wideband reception that receives a signal including a plurality of different carrier frequencies used for communication by the base station apparatus to be evaluated, mixes the signal with a local signal, and converts the signal into an intermediate frequency band that covers the plurality of different carrier frequencies Section (22), an A / D converter (23) for sampling the signal output from the broadband receiving section and converting it into digital waveform data, and waveform data for storing the waveform data converted by the A / D converter A reception storage unit (21) having a memory (24) and acquiring waveform data of a signal output by the base station device at a predetermined time;
Analyzes the waveform data stored in the reception storage unit, detects a signal inserted in a desired time slot in the frame of each carrier frequency, and uses a modulation scheme and measurement items set in advance for the slot. An analysis unit (25) for performing signal demodulation and measurement based on the
A base station evaluation apparatus comprising: a setting unit (30) configured to set modulation method information and measurement item information for each carrier frequency and each slot in a frame for each carrier frequency to the analysis unit;
The analysis unit
The waveform data stored in the reception storage unit is read, and the read waveform data is subjected to frequency conversion processing using local signals of frequencies corresponding to the signal components of the plurality of carrier frequencies, and the plurality of carrier frequencies Each having a signal extraction means (26) for converting each signal component into a baseband,
A base station evaluation apparatus that performs analysis processing set for each signal component converted into a baseband by the signal extraction means. Wideband reception that receives a signal including a plurality of different carrier frequencies used for communication by the base station apparatus to be evaluated, mixes the signal with a local signal, and converts the signal into an intermediate frequency band that covers the plurality of different carrier frequencies Section (22), an A / D converter (23) for sampling the signal output from the broadband receiving section and converting it into digital waveform data, and waveform data for storing the waveform data converted by the A / D converter A reception storage unit (21) having a memory (24) and acquiring waveform data of a signal output by the base station device at a predetermined time;
Analyzes the waveform data stored in the reception storage unit, detects a signal inserted in a desired time slot in the frame of each carrier frequency, and uses a modulation scheme and measurement items set in advance for the slot. An analysis unit (25) for performing signal demodulation and measurement based on the
Signals in the analysis unit of the base station evaluation apparatus comprising: a setting unit (30) for setting the modulation method information and measurement item information for each carrier frequency and each slot in the frame for each carrier frequency to the analysis unit An extraction method comprising:
The waveform data stored in the reception storage unit is read, and the read waveform data is subjected to frequency conversion processing using a local signal having a frequency corresponding to one of the signal components of the plurality of carrier frequencies, The process of converting one of the signal components of the carrier frequency to the baseband is repeatedly performed for each signal component of the plurality of carrier frequencies,
A signal extraction method for a base station evaluation apparatus, wherein a set analysis process is performed for each signal component converted into the baseband.

Images