JP2003169014A - Measuring method for radio communication area - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new measuring method by which a measurement result close to a measurement result based upon sensuous evaluation (e.g. auditory evaluation) can be obtained as a method for measuring the communication area of a base station. <P>SOLUTION: The measuring method for the communication area includes a step S14 in which the information reproducibility or information loss extent of an error-corrected and decoded part of a communication signal having its error corrected and encoded on a transmission side between the base station and radio communication terminal and corrected and decoded on a reception side is detected and a step S16 in which the radio communication area of the base station is obtained according to the information reproducibility and information loss extent obtained as to a plurality of locations of the radio communication terminal. A result which is closer to sensuous evaluation than to evaluation by a bit error rate (BER) is obtained since the communication signal after the error correction and decoding is based upon. Further, it is not necessary to generate a signal dedicated to measurement unlike a case of BER evaluation and measurement can be carried out while normal service is provided. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication area of a base station in a wireless communication system (that is, an area where wireless communication can be performed between a base station and a wireless communication terminal at a predetermined level of quality; for example, a cell, a sector, etc.). The present invention relates to a communication area measurement in a wireless communication system that employs an error correction coding / decoding technique.

[0002]

2. Description of the Related Art Conventionally, communication area measurement in a wireless communication system (for example, a mobile communication system) has been conventionally performed by auditory evaluation in which a person actually listens to a voice demodulated from a communication signal and evaluates its quality, and a demodulated signal. The bit error rate (BER) is evaluated (hereinafter referred to as BER evaluation).

In the hearing evaluation, the voice quality such as the interruption level of the voice demodulated from the communication signal (call signal) wirelessly transmitted between the base station and the wireless communication terminal is, for example, 5.
It is evaluated in stages. This hearing evaluation is performed when the wireless communication terminal is located at a plurality of points at different distances from the base station, and the result shows that the communication area is defined as a range (for example, a range of 4 or more) in which the voice quality satisfies a predetermined criterion. To be measured.

On the other hand, in the BER evaluation, for example, the BER is acquired as a ratio in which bits are erroneously detected in a bit string formed as a known code string. Similar to the above, this BER evaluation is performed when the wireless communication terminal is located at a plurality of points with different distances from the base station, and the communication area is measured from the result as a range in which the BER falls below a predetermined threshold.

[0005]

However, the auditory evaluation is not based on a predetermined physical quantity, and the evaluation result varies depending on the evaluator or even the same evaluator depending on the situation at the time of measurement. Therefore, usually, an average of evaluations by a plurality of evaluators and an average of a plurality of evaluations are often taken, but this takes time and effort.

On the other hand, in the BER evaluation, since the evaluation can be performed by a numerical value based on a predetermined physical quantity, there is no variation like the auditory evaluation. However, B
In the ER evaluation, a communication signal including a dedicated known code string is used, so a circuit configuration for generating the signal is required, and during the BER evaluation, a normal service using the communication signal (for example, Voice call) must be stopped. Further, since the communication signal including the known code sequence for evaluation is different from the actual communication signal, B
There may be a large difference between the measurement result of the communication area by the ER evaluation and the measurement result of the communication area by the auditory evaluation.

[0007]

A wireless communication area measuring method according to the present invention is a method for measuring a wireless communication area of a base station, wherein error correction coding is performed on the transmitting side of the base station and the wireless communication terminal. In the communication signal that has been error-corrected and decoded at the receiving side, the step of detecting the information reproducibility or the information loss degree of the error-correction-decoded portion, and the step of acquiring the information regarding the plurality of positions of the wireless communication terminal, respectively. Acquiring the wireless communication area of the base station based on the information reproducibility or the information loss.

Error correction coding / decoding techniques are employed in many wireless communication systems. In this case, even if some error exists in the bit string, if the error is correctable (for example, within the Hamming distance), the error bit is accurately reproduced and the output becomes normal. On the other hand, if an uncorrectable error occurs,
Abnormality occurs in the output on the receiving side. That is, the communication signal after being error-correction-decoded is a signal closer to the signal actually output from the receiving side than the signal used in the BER evaluation, and thus is error-correction-decoded as in the present invention. The area measurement result based on the information reproducibility or the information loss degree of the part is closer to the area measurement result based on the sensory evaluation (for example, auditory evaluation) than the area measurement result based on the BER evaluation.

Further, according to the present invention, unlike the BER evaluation, it is not necessary to generate a dedicated signal, and the area measurement can be performed by using a communication signal which is normally used. A circuit for generating a signal is not needed, and area measurement can be performed without stopping service by a normal communication signal.

Further, in the present invention, the step of detecting the information reproducibility or the information erasure degree further detects the information reproducibility or the information erasure degree of a portion which is interleaved on the transmitting side and deinterleaved on the receiving side. Is preferred.

The interleaving / deinterleaving process is a technique for rearranging bits to disperse burst errors into random errors and improve reproducibility by error correction. When this interleave processing technology is used for signal processing of communication data, the area measurement result based on the information reproducibility or the information loss degree of the deinterleaved part is closer to the area measurement result based on the sensory evaluation. Can be said.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a communication area measuring system 12 including communication area measuring devices 10a and 10b according to an embodiment of the present invention.

In the communication area measuring system 12, the area of the base station 14 is measured using the communication signal wirelessly transmitted between the base station 14 and the wireless communication terminal 16. In the present embodiment, the wireless communication terminal 16 is mounted on, for example, a vehicle 18, and when the wireless communication terminal 16 is located at a plurality of points, it is possible to perform measurement for communication area measurement.

The base station 14 includes a communication area measuring device 10
a (for example, a computer or the like) is connected or built in, and a communication terminal (for example, a fixed telephone or the like) 20 for transmitting a communication signal is connected. In addition to the wireless communication terminal 16, the vehicle 18 includes a communication area measuring device 10 that is connected to the wireless communication terminal 16 and performs various processes related to area measurement.
b (for example, a computer) and the communication area measuring device 1
A position detection device (for example, a GPS device) 22 connected to 0b for detecting the position of the vehicle 18 (that is, the position of the wireless communication terminal 16) is mounted.

The communication signal transmitted by the communication area measuring system 12 has a frame structure as shown in FIG. 2, for example. In this example, one frame of a communication signal includes a linearizer preamble LP (30 bits), a preamble P (2 bits), a traffic channel TCH (96 bits), a radio information channel RICH (56 bits), and a synchronization word SW (20 bits). ), An undefined part (20 bits), and a traffic channel TCH (160 bits), a total of 384 bits. this house,
The traffic channel TCH is a channel that carries transmission target information such as voice signals and image data, and the radio information channel RICH is a channel that carries information for controlling communication.

In the example of FIG. 2, the portion of the communication signal that is error-correction coded and interleaved by the transmitter and deinterleaved and error-corrected by the receiver is traffic channel TC.
H and radio information channel RICH. These traffic channel TCH and radio information channel RIC
H is subjected to encoding / decoding processing as shown in FIG. 3 on the transmitting side and the receiving side. For the information carried on these two channels (TCH, RICH),
Transmitting side device (that is, base station 14 and wireless communication terminal 1
In any one of 6), coding for error detection (for example, CRC coding), error correction coding (for example, convolutional coding), and processing for improving error correction capability (for example, interleaving processing) are performed. In the receiving device (that is, the other of the base station 14 and the wireless communication terminal 16), a process corresponding to the process of improving the error correction capability (for example, deinterleaving process), error correction decoding (for example, Viterbi decoding), And error detection decoding (eg CRC decoding) is performed. The communication area measuring devices 10a and 10b are connected to the receiving side device (the base station 14 or the wireless communication terminal 16), and the receiving side device performs error detection decoding (traffic channel TC in the example of FIG. 3).
H or the result of CRC decoding of the radio information channel RICH) is acquired, and the area measurement processing described later is executed. The receiving side apparatus acquires the result of error detection and decoding (success or failure of error correction) for each frame.

Here, the communication area measuring process by the communication area measuring devices 10a and 10b will be described with reference to FIG. FIG. 4 is a flowchart showing an example of the communication area measuring method.

First, the communication area measuring devices 10a and 10b
Acquires the position of the wireless communication terminal 16 from the position detection result of the position detection device 22 (step S10). This position is acquired as indicating the position of the wireless communication terminal 16 when the communication signal to be processed is transmitted in the subsequent steps S12 and S14. If the position detection device 22 is a GPS device, the position coordinates (latitude, longitude) of the wireless communication terminal 16 are acquired in step S10.

A communication signal is transmitted between the base station 14 and the wireless communication terminal 16 in a state where the position of the wireless communication terminal 16 is fixed (step S12). At this time, in the transmitting side device and the receiving side device, processing relating to error correction, error detection, and interleaving as shown in FIG. 3, for example, is performed, and communication is performed from the receiving side device (base station 14 or wireless communication terminal 16). An error detection result (success or failure of error correction) for each frame of the signal (TCH or RICH) is output to the communication area measuring device 10a or 10b.

The communication area measuring devices 10a and 10b acquire the error detection results for each frame for a plurality of preset frames (consecutive frames) and acquire the information reproducibility or the information loss (step S14). Note that the information reproducibility indicates, for example, the ratio of the number of frames that have been error-corrected to the number of acquired frames, and the information loss degree, for example, cannot correct the errors to the acquired number of frames. The ratio of the number of frames is shown.

In the case of the examples of FIGS. 2 and 3, the traffic channel TCH and the radio information channel RICH are subjected to substantially the same processing on both the transmitting side and the receiving side, so that the information reproducibility or information loss is obtained. Either of these two channels may be adopted as the target. In this example, the traffic channel TCH
In the case of using, since the number of bits is large, it is possible to acquire the information reproducibility or the degree of information loss more accurately and more quickly than in the case of using the radio information channel RICH. However, in the case of the traffic channel TCH, since the encoding / decoding processing differs depending on the data to be loaded, the communication area measuring device 10a, 10a,
The trouble of switching the processing occurs in 10b, and accordingly,
Compared to the case where the radio information channel RICH in which the data type does not change is used, the time and effort required for the processing are increased. It is also possible to put a known code (for example, a cyclic code; a PN code or the like) on the traffic channel TCH and obtain the information reproducibility or the information loss degree from this.

The communication area measuring devices 10a and 10b measure the communication area from the result of executing the above steps S10 to S14 at a plurality of location points of the wireless communication terminal 16 (step S16). This will be described with reference to FIG. FIG. 5 is a diagram showing the correlation between the distance of the wireless communication terminal 16 from the base station 14 and the information erasure rate (MER) acquired by the communication area measuring device 10a or 10b. In FIG. 5, the horizontal axis indicates the distance from the base station 14 (the right side is longer), and the vertical axis indicates the MER.
(Higher on the lower side). From the results of executing steps S10 to S14 at a plurality of location points of the wireless communication terminals 16 having different distances from the base station 14, for example, the MER as shown in p1 to p5 of FIG. 5 is acquired. Then, the communication area measuring devices 10a and 10b estimate the distance-MER characteristic as shown by the solid line in FIG. 5 from these data,
The distance Lb (or position) that becomes the area boundary is acquired as the point where the MER becomes the threshold Mth corresponding to the area boundary. For reference, FIG. 5 shows the BER acquired under the same conditions as the acquisition of the MER.
It can be seen that there is a large difference with the ER characteristics.

In the above embodiment, the information loss rate ME
Although an example of performing area measurement using R is shown, it can be easily understood that the same result can be obtained when the information recall is used.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a communication area measuring system including a communication area measuring device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration example of one frame of a communication signal used in the communication area measuring apparatus according to the embodiment of the present invention.

FIG. 3 is a diagram showing an example of a procedure of encoding and decoding a communication signal used in the communication area measuring apparatus according to the embodiment of the present invention.

FIG. 4 is a flowchart showing a communication area measuring method according to the embodiment of the present invention.

FIG. 5 is a diagram showing an example of the correlation between the distance between the base station and the wireless communication terminal and the degree of information loss, which is acquired by the communication area measuring method according to the embodiment of the present invention.

[Explanation of symbols]

10a, 10b communication area measuring device, 12 communication area measuring system, 14 base stations, 16 wireless communication terminals, 1
8 vehicles, 22 position detection device.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5K014 AA01 BA06 FA16 GA01                 5K042 AA06 CA02 CA23 DA27 EA15                       GA12                 5K067 AA21 BB04 DD51 EE02 EE10                       HH26 LL11

Claims (3)

[Claims] 1. A method for measuring a wireless communication area of a base station, wherein a communication signal error-correction-encoded at a transmission side and error-correction-decoded at a reception side of a base station and a wireless communication terminal, A step of detecting the information reproducibility or the information loss of the error-correction-decoded portion; and the radio of the base station based on the information reproducibility or the information loss acquired respectively for a plurality of positions of the wireless communication terminal. A method of measuring a wireless communication area, comprising: acquiring a communication area. 2. The step of detecting the information reproducibility or the information erasure level further comprises detecting the information reproducibility or the information erasure level of a portion which has been interleaved on the transmitting side and deinterleaved on the receiving side. The method for measuring a wireless communication area according to claim 1. 3. A wireless communication area measuring device for measuring a wireless communication area of a base station, wherein the transmitter side of the base station and the wireless communication terminal performs error correction coding and the receiving side performs error correction decoding. In the communication signal, the information state detection unit that detects the information reproducibility or the information erasure of the error-correction-decoded part, and the information reproducibility or the information erasure obtained for each of a plurality of positions of the wireless communication terminal are used. A wireless communication area measuring device including a wireless communication area acquisition unit that acquires a wireless communication area of the base station based on the wireless communication area measuring device.