JPH04313926A - Communication system - Google Patents

Abstract

PURPOSE:To keep always high communication quality by selecting an operating frequency based on the frequency order obtained by a radio wave state measurement section so as to use a communication line in excellent state. CONSTITUTION:A reception antenna 2 and a receiver 3 monitor the presence of noise and a disturbing radio wave and its degree at a frequency other than that of a busy communication channel and outputs the result to a communication controller. The S/N, a noise level or a disturbing wave level in the operating communication channel is monitored by inputting part of an output of a reception section of a transmitter-receiver 1 to the communication controller 4 and when the level or the like is deteriorated to be a prescribed level or below, the other best communication channel is selected based on the result of evaluation of the other communication channel. When the communication channel to be selected is decided, a signal representing the channel is sent from the communication controller 4 to a communication opposite party. Thus, the results of evaluation of own communication channels are linked and the base channel for the both is decided.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication system that maintains and improves communication quality in frequency hopping communication and general communication.

0002

2. Description of the Related Art For example, when wireless communication is performed between two points, if interference radio waves enter the communication channel being used, the quality of the communication may deteriorate significantly and communication may become impossible.

[0003] In particular, when performing ionospheric propagation communication using a relatively low frequency communication channel such as HF, the radio wave propagation state changes moment by moment.

[0004] Conventionally, in cases like this, communication has been interrupted and waiting for the spatial situation to recover, or both the sender and receiver have consulted with each other and sequentially change the assigned frequencies until they come across a frequency with good conditions. Communication is continued by performing operations.

[0005] However, in such conventional methods, since the status of other frequencies cannot be known in advance, switching to the optimum frequency is inefficient and there is a risk of line disconnection.

[0006]Furthermore, as another communication method, a frequency hopping communication method is known, which is intended for concealment of communication contents, but conventionally, the frequency is changed without knowing the status of each channel in advance. Therefore, communication quality often worsened.

[0007] In addition to the above, when a preset time arrives, the "daytime frequency" is changed to the "nighttime frequency".
In addition, shortwave communication systems that switch from "nighttime frequencies" to "daytime frequencies" are also known, but even in such communication systems, communication quality inevitably deteriorates depending on the spatial conditions.

[0008]

[Object of the Invention] In view of the above circumstances, it is an object of the present invention to provide a communication system that can switch to a communication line in good condition by knowing the status of other frequencies at the current time and maintain high communication quality at all times. It is an object.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the communication system according to the present invention sequentially monitors each of a plurality of pre-assigned communication channels for the presence of interference waves or noise, and selects communication channels with good conditions. In addition to storing information in sequence, the communication channel is sequentially changed while notifying the communication partner of the communication channel to be selected next; The communication channel is then switched according to the stored order.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below based on embodiments shown in the drawings.

FIG. 1 is a block diagram showing an embodiment of a communication system to which a communication method according to the present invention is applied.

In the figure, 1a and 1b are transmitting/receiving devices for communication.

Each transmitting/receiving device 1a, 1b has a receiving antenna 2a, 2b, a receiver 3a, 3b, and a communication control device 4, respectively.
a, 4b, transmitter/receiver 5a, 5b, and transmitting/receiving antenna 6
a, 6b, and performs conventional communication using a transmitter/receiver 5a (5b) and a transmitting/receiving antenna 6a (6b).

[0014] At the same time, or intermittently as necessary,
The reception antenna 2a (2b) and the receiver 3a (3b) monitor the presence and extent of noise and interference waves at frequencies other than the communication channel in use, and the results are sent to the communication control device 4a (4b). Output to.

The communication control device quantifies the noise level and interference wave level for each communication channel, compares the numerical values of each communication channel, prioritizes them in order of best evaluation, and stores them in the memory circuit. Remember.

[0016] Monitoring of such communication channels is carried out constantly or cyclically at predetermined intervals, and the contents of the memory circuit are updated every time all other communication channels are scanned, so that new monitoring results are always available. Remember. In this state, the S/N of the communication channel in use
ratio and noise level or interference wave level to the transmitter/receiver 1a.
A part of the output of the receiving section (1b) is transmitted to the communication control device 4a (4b).
), and when the monitoring result deteriorates below a predetermined level, the best other communication channel is selected based on the above-mentioned other communication channel evaluation results.

When the communication channel to be selected next is determined, a signal indicating the communication channel to be selected is transmitted from the communication control device 4a to the communication partner via the transceiver 1a and the antenna 6a.

[0018] The communication partner receiving this signal checks whether the evaluation of the communication channel to be selected next by its own communication control device is good or bad, and if it is good, it will notify that fact, and if it is bad, it will , generates a signal specifying an alternate communication channel and transmits it back to the communicating party via its transceiver and antenna.

[0019] In this way, while communicating the results of their own communication channel evaluations, both sides determine the best channel, and then switch over at the same time in synchronization. According to this method, if the communication quality in the communication channel in use deteriorates due to interference waves, noise, fading, etc., it becomes possible to quickly switch to another communication channel with the best conditions.

[0020] This idea can also be applied to frequency hopping communication systems.

[0021] In other words, frequency hopping communication involves switching frequencies one after another in a relatively short period of time, mainly to improve confidentiality. A hopping pattern is determined in advance for both transmitting and receiving sides, and communication is carried out in synchronization with each other. This is a method to do so.

Therefore, as described above, before starting communication on a large number of frequencies (communication channels) allocated for hopping, the presence or absence of noise level interference waves and the level of each are monitored, and a communication channel suitable for use is selected. Select and create a frequency hopping pattern.

[0023] At this time, when transmission and reception are performed unilaterally, priority should be given to channel evaluation on the receiving side, but when transmission and reception are performed simultaneously or alternately, evaluation of both sides should be given priority. The hopping pattern is determined after comparing the two.

As described above, in this embodiment, when the spatial condition of the frequencies being transmitted and received by each transmitter/receiver 5a, 5b deteriorates, the spatial condition is measured by each receiver 3a, 3b, and this measurement result is Since the frequency with the best condition (best frequency) is selected based on the frequency and the transmitting/receiving frequency of each transceiver 5a, 5b is switched to the best frequency, the condition of other frequencies at that time can be known. This makes it possible to always maintain high communication quality using a communication line in good condition.

Furthermore, in the embodiment described above, when interference or interference with the radio waves transmitted and received by each transmitter/receiver becomes severe, the radio waves are switched to the radio waves of the best frequency. Even when the current frequency is not available, the currently used frequency may be sequentially switched to the best frequency other than this frequency to improve the anti-interception property.

[0026]

As described above, according to the present invention, by knowing the status of other frequencies at that time, it is possible to use a communication line in good condition and maintain high communication quality at all times.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of a communication system to which an embodiment of a communication method according to the present invention is applied.

[Explanation of symbols]

1 Transmitting/receiving device, 2 Receiving antenna, 3 Receiver, 4 Communication control device (radio wave condition measuring section), 5 Transmitting/receiving device (Transmitting/receiving section), 6 Transmitting/receiving antenna,

Claims (2)

[Claims] Claim 1: The presence or absence of interference waves or noise in each of a plurality of pre-assigned communication channels is sequentially monitored, communication channels with good conditions are stored in order, and the communication channel to be selected next is transmitted. A communication method characterized by sequentially changing communication channels while contacting the other party. 2. The communication system according to claim 1, wherein the transmitter/receiver switches the communication channel according to the stored order when the radio wave condition of the currently used frequency deteriorates.