Multiplex communications – Diagnostic testing
Reexamination Certificate
1999-11-17
2003-02-11
Le, Thanh Cong (Department: 2684)
Multiplex communications
Diagnostic testing
C370S335000, C370S342000
Reexamination Certificate
active
06519227
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to W-CDMA analysis to measure and analyze the power value contained in a transmitted and received signal in each communication channel in a mobile communication system and the like on the W-CDMA system and also relates to display of results of the analysis.
2. Related Art
CDMA (Code Division Multiple Access) is a system to divide a communication path into a plurality of communication channels by assigning a specific code to each individual communication path thereby modulating the carrier wave with the code. The mobile communication system on the CDMA system is excellent in terms of communication quality and put to practical use also in Japan. Recently, development is being made of the mobile communication system employing W (Wideband)-CDMA system capable of transmitting a mixture of voice, image, and various other signals to meet the demands for multimedia applications and others.
One of the characteristic features of the W-CDMA is its capability of multi-rate transmission. For example, it can provide a service at a slow transmission rate for users who want to transmit and receive only a voice signal and provide a service at a high speed transmission rate for user who want to transmit and receive image data and the like at high speeds.
In the W-CDMA system, in general, a pseudo random (PN) code is used to realize spread spectrum and the PN signal is generated on the receiver side to de-spread the data spread on the transmitter side. There are short codes with low cycles and long codes with high cycles in the PN codes, and different short codes are set corresponding to individual communication channels.
The level of the spreading signal spread by using such codes is lowered to 1/100 or so of the level of the original signal. Therefore, when making analysis of power of a received signal, code domain power analysis is generally used in which measurement is made for each communication channel.
FIG. 5
is a drawing showing a display example of results of code domain power analysis in the conventional method, in which there are shown results of measurement of the power value for each short code contained in a received signal that was obtained by receiving a radio wave transmitted from a base station or a mobile station. Referring to
FIG. 5
, the axis of abscissas represents the short code numbers assigned to individual short codes and the axis of ordinates represents the power values in the communication channels corresponding to the short codes. For example, it is known from the drawing that there are used four communication channels corresponding to four short codes specified by the short code numbers “0”, “5”, “10”, and “15” and what the power value in each of the communication channel is.
However, in the above display example showing results of conventional code domain power analysis, though the short code number of each channel used for signal transmission can be known, the symbol rate (transmission rate) of each channel cannot be known. Specifically, while multi-rate transmission is possible in communications on the W-CDMA system as described above, the symbol rate is required to be known in analyzing the measured power value. Therefore, it is convenient for the user if the symbol rate can be known related with the short code number corresponding to the measured power value.
SUMMARY OF THE INVENTION
The present invention was made in view of the above described problem and it is an object of the invention to provide a W-CDMA analyzing apparatus as well as a method of displaying results of W-CDMA analysis making it possible at the time of power measurement to know the symbol rate in connection with the code number and a recording medium carrying record of a program for displaying results of W-CDMA analysis.
The present invention may include: a frequency conversion unit, which receives a signal transmitted and received in communication employing the W-CDMA system, for converting the received signal into an intermediate-frequency signal; a signal analysis unit, which applies a predetermined spreading demodulation process to an intermediate-frequency signal outputted from the frequency conversion unit, for calculating the power value of each pseudo random code; and a display unit for displaying the power value of the signal for each of the pseudo random codes calculated by the signal analysis unit in such a way that the power value is related to the code number assigned to each of the pseudo random codes and the value of the symbol rate corresponding to each of the pseudo random codes is discernible.
According to the W-CDMA analyzing apparatus designed as described above, when a frequency conversion process is applied to a signal transmitted and received in communication employing the W-CDMA system and then the power value of each of the pseudo random codes is calculated and the results of calculation are displayed, the display is made in such a way that the power value is related with the code number of the pseudo random code and the value of the symbol rate corresponding to each pseudo random code is discernible.
Accordingly, it becomes possible to know the power value corresponding to each pseudo random code and the corresponding symbol rate at the same time.
In the invention described above, the display unit may set the bar width of the bar graph in proportion to the value of the symbol rate while displaying the power value corresponding to each of the code numbers in the form of a bar graph with the code number related to one of two axes orthogonal to each other and the power value related to the other axis.
Specifically, by setting the bar width of the bar graph indicating the power value in proportion to the value of the symbol rate when the display is made in the form of a bar graph with the code number related to one of two axes orthogonal to each other and the power value related to the other axis, it is made easy for the user, when measuring the power value, to relate the code number of the pseudo random code with the symbol rate of the corresponding communication channel.
In the invention described above, the symbol rate corresponding to the scale having the division thereof in agreement with the bar width of the bar graph may be set as the symbol rate of the communication channel for which the power value was measured while one of the axes related with the code number is provided, along the same, with a plurality of scales each thereof having the division of the scale corresponding to each symbol rate.
It is an advantage, when a display is made with the bar width of the bar graph varied as described above, that there are provided along the axis corresponding to the code number a plurality of scales having divisions of the scale in proportion to their respective symbol rates. By specifying the division of the scale having the same size as the bar width of the bar graph, accurate identification of the corresponding symbol rate can be made.
In the invention described above, the display unit may make different coloring according to the value of the symbol rate corresponding to the communication channel while providing a predetermined graph display with the code number related to one of two axes orthogonal to each other and the power value related to the other axis.
As described above, apart from providing a display with the symbol rate related to the bar width of the bar graph, giving different coloring according to the value of the symbol rate when providing a bar graph or other graph display can also relates the code number of the pseudo random code with the symbol rate of the corresponding communication channel.
The present invention my include a method of displaying results of W-CDMA analysis for displaying results of measurement of the power value of signal for each communication channel included in a received signal, and it includes the step of,—displaying the power value of each pseudo random code corresponding to each of the communication channels as related to the code
Advantest Corporation
Cong Le Thanh
Lowe Hauptman & Gilman & Berner LLP
Tran Tuan
LandOfFree
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