JP2002026923A - Self-proliferating wireless distribution network - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a self-proliferating wireless distribution network that is immune to the effect of an increased noise level due to loop oscillation and an interference wave and can build up a stable and excellent wireless distribution network in a sort time depending on the operating state of a radio wave, which cannot have been realized with a conventional self-proliferating wireless distribution network. SOLUTION: Each of reception stations 9, 10, 11, 12, and 13 being components of a network is provided at least with a means that transmits identification information of transmission stations denoting all transmission stations having been passed through until reaching a concerned reception station and including itself in the case of re-transmission, and also provided with a discrimination means that discriminates whether or not a radio wave received at present should be switched over to other radio wave on the basis of the comparison between measured values of a reception C/N and a transmission stage number identified from identification information of the transmission stations as to respective radio waves received by the reception station and a preset transmission stage number threshold value and a preset reception C/N.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network using radio waves, and more particularly to a self-propagating wireless distribution network constituted by receiving stations having a retransmission function.

[0002]

2. Description of the Related Art In the present invention, retransmission means that all or a part of information received by radio waves is transmitted using radio waves having the same frequency as the frequency of the received radio waves or a frequency different from the received frequency. Say, send again.

If the receiving station unconditionally performs retransmission, loop oscillation occurs at the same frequency or the noise level increases due to interference waves, making it difficult to construct a stable and good wireless distribution network. For this reason, wireless distribution networks that perform retransmission are conventionally used in wireless distribution networks based on one-to-one communication as described below.

[0004] In other words, for multistage relay in terrestrial television broadcasting and fixed micro-circuits in communication, the operator owns both the transmitting station and the receiving station, and the operator manages and grasps the status of frequency use. , Avoiding the above problem due to retransmission. When a temporary network is formed between terminals in the field of mobile computing or the like, the above-described problem due to retransmission is avoided by performing bidirectional communication between terminals.

[0005]

However, in a wireless distribution network (one-to-N communication), a mode is usually adopted in which a receiving station directly receives radio waves from a base station owned by a business operator. Typical examples thereof include individual reception at each home in terrestrial television broadcasting and information transmission from a base station to a terminal by a mobile phone or the like.

[0006] In the radio distribution network of this form, even if the receiving terminals that should receive information are adjacent to each other, the service cannot be enjoyed unless a line can be set up from the base station to each receiving terminal. . This means that from the viewpoint of the service provider, it is necessary to newly install a base station in order to satisfy the needs of a small number of receivers who cannot receive the service. Therefore, there is a problem that it takes a lot of time and cost to install the base station in order to construct a wireless distribution network in which the radio waves of the base station are directly received.

SUMMARY OF THE INVENTION An object of the present invention is to be less susceptible to the effects of noise caused by loop oscillations and interference waves, and to construct a stable and good wireless distribution network in a short time according to the use of radio waves. To provide such a self-propagating wireless distribution network

[0008]

To achieve the above object, a self-propagating wireless distribution network according to the present invention comprises a base station and a plurality of receiving stations having a retransmission function. In each of the receiving stations constituting the network, when performing retransmission,
Means for transmitting the identification information of the transmitting station indicating all the transmitting stations that have passed through to the receiving station, including the receiving station;
The number of transmission stages and reception CN identified from the identification information of the transmission station for each radio wave received by the reception station.
Whether to switch the currently received radio wave to another received radio wave based on a comparison between the measured ratio and a preset threshold value of the number of transmission stages and a preset threshold value of the reception CN ratio. And at least a determination means for determining whether

In the self-propagating wireless distribution network according to the present invention, the determination is made that the number of transmission stages is smaller than the preset threshold value of the number of transmission stages and the measured value of the reception CN ratio is set to the predetermined value. Received CN
It is characterized by satisfying that the ratio is higher than the threshold value of the ratio and determining whether or not the transmission stage number is the smallest.

In the self-propagating wireless distribution network according to the present invention, when the judgment is that there are a plurality of transmission stages with the smallest number of transmission stages, a network having the highest measured value of the reception CN ratio is selected from them. It is characterized in that it is performed so that

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on embodiments of the present invention with reference to the accompanying drawings. Figure 1
Is an example of a configuration example of a wireless device A that configures a self-propagating wireless distribution network of the present invention together with a base station and another wireless device that performs retransmission and that performs retransmission at the same frequency (f ₁ ) as a received radio wave. This is shown in a block diagram. In FIG. 1, 1 is a main line system, 2 is a receiving circuit-I, 3 is a control unit, 4 is a transmitting circuit, 5 is a received radio wave selection system, 6 is a received radio wave separation unit,
And 7 are a receiving circuit-II.

The operation will be described. In main line system 1, wireless
Radio waves arriving at device A (all incoming radio waves are frequency
(F ₁ Select the radio wave to be received from))
Retransmission control is performed according to conditions. Receiver circuit indicated by reference numeral 2
-I is a reception CN ratio of a radio wave received by the receiving circuit-I.
Is measured, and the measured value and the radio wave
The identification information of all the transmitting stations through which the
Read it and send it to the control unit 3. Measured in the receiving circuit-I
The received CN ratio is set to the preset CN in the control unit 3.
If the ratio is lower than the threshold value, the control from the control unit 3
Switching of received radio wave by signal (switching control)
U. Note that the reception CN ratio in the receiving circuit-I is transmitted to the control unit 3.
When it is higher than the preset CN ratio threshold
Does not switch the received radio wave. This is the radio wave
This is to avoid switching more than necessary.
You.

In the transmitting circuit 4, received radio waves are switched or not transmitted as described above, and the retransmitted radio waves are used to identify all transmitting stations from the base station to the wireless device A. Information is added, and retransmission is performed at the same frequency (f ₁ ) as the received radio wave. Retransmission control is also performed by a control signal (retransmission control) from the control unit 3.

Next, the reception radio wave selection system 5 separates a plurality of radio waves arriving at the radio apparatus A in time and space,
Monitoring is performed for each of the classified signals. First, the received radio wave separating unit 6 classifies the received radio waves into different radio waves or radio waves having different delay times due to reflections of buildings, for example, by using the arrival direction of the radio waves and the delay time of the arrival of the radio waves. , 7, respectively. The receiving circuit-II measures the received CN ratio for each of the received radio waves, decodes the identification information of all the transmitting stations that have passed through to the wireless device A, and decodes the information (the received CN ratio, the transmission CN ratio). Control unit 3).
Send to In addition, in addition to the above, a threshold value of the number of transmission stages is set in the control unit 3 (see FIG. 1).

As described above, the control unit 3 first
It is determined whether switching control is necessary based on the measured value of the reception CN ratio of the radio wave received by the reception circuit-I indicated by reference numeral 2. At this time, if the received CN ratio is lower than the CN ratio threshold set in the control unit 3 in advance, the CN of each received radio wave obtained by the receiving circuit-II indicated by reference numeral 7
Based on the measured value of the ratio and the identification information of the transmitting station that has passed, a radio wave to be received, that is, a radio wave to be retransmitted is selected in the following procedure.

First, from among the candidates for the received radio waves supplied to the receiving circuit-II, those that do not satisfy the above-described conditions of the threshold value of the reception CN ratio and the threshold value of the number of transmission stages are excluded. Next, the identification information of the transmitting station that includes the identification information of the wireless device A is excluded from the candidates because loop oscillation occurs. As described above, a candidate having a small number of transmission stages is selected from those remaining as candidates. When a plurality of transmission stages having the same number of transmission stages are selected, the one having the highest measured value of the reception CN ratio is selected among them. When the number of switching candidates is reduced to one by the above procedure, the control unit 3 receives a control signal (switching control) for performing the switching process at a timing set for each network by a receiving circuit-I indicated by reference numeral 2. Send to If no switching candidates remain after the above procedure,
The received radio wave is not switched.

In the above description, it is conceivable that the switching of the radio wave to be received occurs when the reception CN ratio greatly changes due to shielding by a building or a tree, installation of a new base station or a receiving station, attenuation by rainfall, or the like. The receiving circuit-I denoted by reference numeral 2 selects a radio wave to be received from the incoming radio waves according to the switching control from the control unit 3. For the selection of the radio wave, the classification method performed by the received radio wave classification unit 6 is used. For example, when only the information of the direction of arrival of the radio wave is used in the received radio wave separation unit 6, the receiving circuit-I changes the directivity of the receiving antenna connected to the receiving circuit electrically or mechanically, It is assumed that a radio wave arriving from a desired direction (a radio wave to be selected) is received.

As described above, the radio apparatus A retransmits the radio wave received by the receiving circuit-I indicated by the reference numeral 2 in principle, and the number of transmission stages of the radio wave from the base station is transmitted to the control unit 3 in advance. If it is greater than the threshold you set,
Alternatively, when the measured value of the received CN ratio is lower than a threshold value set in advance in the control unit 3, the retransmission is not performed because the disadvantage of performing the retransmission as it is is large. In order to perform such an operation, the control unit 3 stops the retransmission at the timing set for each network,
Then, retransmission control is performed on the transmission circuit 4 so as to start the retransmission.

In the self-propagating radio distribution network of the present invention, the radio equipment constituting the radio transmission network decodes the identification information of the transmitting station multiplexed on the received radio wave and transmits the transmitted radio wave to the receiving station. It is necessary to multiplex the identification information of all the transmitting stations that have passed. As the identification information of the transmitting station, any one of frequency, time, and code is multiplexed using the existing technology.

FIG. 2 is a schematic diagram showing a first embodiment of the self-propagating wireless distribution network of the present invention. FIG.
In, 8 is a base station

[Outside 1] , 9 is the receiving station

[Outside 2] , 10 is the receiving station

[Outside 3] , 11 is the receiving station

[Outside 4] , 12 is the receiving station

[Outside 5] And 13 is the receiving station

[Outside 6] Are respectively shown. In the following, the receiving stations [outside 2] 9, [outside 3] 10, [outside 4] 11, [outside 5] 12,
When [Ex. 6] 13 retransmits, these receiving stations will be referred to as transmitting stations [Ex. 2], [Ex. 3], [Ex. 4], [Ex. 5], and [Ex. 6], respectively. In addition, when the base station [external 1] 8 is counted as the first stage of the transmitting station and the station becomes the fourth stage or later, retransmission is not performed, and the threshold value of the CN ratio is set to 20 dB. . Note that, in FIG. 2, a character string surrounded by angle brackets represents identification information of the transmitting station.

The operation will be described. First, the base station [outside 1] 8 emits a radio wave by adding identification information “N” indicating that “this radio wave is transmitted from the base station [outside 1] 8”. Radio waves emitted from the base station [outside 1] 8 are received by the receiving station [outside 2] 9 and the receiving station [outside 3] 10
Can be received directly. When the receiving station [ex. 2] 9 retransmits the received radio waves,
It passes through the base station [external 1] 8 and the transmitting station [external 2], and retransmits it. Similarly, the receiving station [outside 3] 10 adds identification information "N, sa" indicating that "this radio wave has passed through the base station [outside 1] 8 and the transmitting station [outside 3]". And resubmit.

Further, since the receiving station [outside 4] 11 can receive the radio wave of the transmitting station [outside 3], "this radio wave is transmitted to the base station [outside 1] 8, the transmitting station [outside 3], 4]], the identification information “N, sa,
And resend it. Similarly, since the receiving station [outside 5] 12 can receive the radio wave of the transmission station [outside 2], “this radio wave is transmitted to the base station [outside 1] 8 and the transmission station [outside 2].
And "N, so, mi" indicating that the transmission has been performed via the transmission station [external 5]. "

Further, the receiving station [outside 6] 13 can receive the radio waves of the transmission station [outside 5], the transmission station [outside 3], and the transmission station [outside 4]. Is received by the receiving circuit 7 (receiving circuit-II) in the wireless device A shown in FIG. The transmitting station identification information of each received radio wave, the number of transmission stages,
The measured values of the received CN ratio are shown in FIG. First, the measured value of the reception CN ratio of the radio wave from the transmission station [3] is excluded because it does not satisfy the threshold value (20 dB) of the reception CN ratio. Radio waves from the transmitting station [outside 5] and the transmitting station [outside 4] do not include identification information of the own station (identification information of the transmitting station [outside 6]). Also, the number of transmission stages is equal in three stages.
Therefore, the radio wave with the higher reception CN ratio, that is, the radio wave from the transmitting station [outside 5] is selected.

When the radio wave from the transmitting station [outside 5] is selected in this way, the receiving station [outside 6] 13 is at the fourth stage counted from the base station [outside 1] 8 and does not retransmit. In this way, the receiving station performs retransmission based on the predetermined condition, so that the wireless distribution network can be configured in a short time.

FIG. 3 is a schematic diagram showing a second embodiment of the self-propagating wireless distribution network according to the present invention. FIG.
Is different from FIG. 2 in that the propagation route from the transmitting station [outside 5] to the receiving station [outside 6] 13 is shielded in the configuration of the wireless distribution network shown in FIG. At the receiving station [outside 6] 13, the radio waves of the transmission station [outside 3] and the transmission station [outside 4] are received. FIG. 3 shows the measured values of the transmission station identification information, the number of transmission stages, and the reception CN ratio of each received radio wave. Control unit 3 in wireless device A shown in FIG.
According to the procedure described in the above operation, in the case of the present embodiment, the radio wave of the transmitting station [outside 4] is selected, and the received radio wave is switched at the timing determined by the network.

Even if the received radio wave is switched, the receiving station [outside 6] 13 is at the fourth stage counted from the base station [outside 1] 8 and does not retransmit. According to the present invention, as described above, the receiving station performs retransmission one after another on the basis of a predetermined condition, whereby a redundant propagation route can be secured, and therefore, the reliability of each propagation route is low. However, reliability as a wireless distribution network can be ensured.

FIG. 4 is a schematic diagram showing a third embodiment of the self-propagating wireless distribution network according to the present invention. FIG.
Fig. 4 shows a case where the propagation route has a reflection from a building in the configuration of the wireless distribution network shown in Fig. 2. In the receiving station [outside 3] 10, in addition to the direct reception from the base station [outside 1] 8, the radio wave of the own station is reflected by the building 14 (the base station [outside 1] 8 and the transmitting station [outside 3]) ) Is also received. The two radio waves are received as candidates by the receiving circuit 7 (receiving circuit-II) in the wireless device A shown in FIG. If the latter is selected, a loop oscillation occurs, and the base station [external 1] 8
Radio waves from the phone do not reach. However, as described in the operation of the control unit 3 in the wireless device A, since the radio wave including the identification information of the own station (as the transmitting station) does not remain as a candidate, switching of the radio wave to receive it is not possible. Does not occur.

In the above description, the case where the received radio wave and the retransmitted radio wave at the receiving station have the same frequency has been described.
Similar effects can be obtained when the received radio wave and the retransmitted radio wave have different frequencies. FIG. 5 uses two frequencies f ₁ and f _{2. When} the frequency of the received radio wave is f ₁ , retransmission is performed at the frequency f ₂ , and the frequency of the received radio wave is f ₂
In the case of, a configuration example of the wireless device B that retransmits at the frequency f ₁ is shown in a block diagram. In FIG. 5, the circuit configuration is basically the same as that shown in FIG.
The receiving circuit 2 (receiving circuit-I), the transmitting circuit 4, the received radio wave separation unit 6, and the receiving circuit 7 (receiving circuit-II)
It differs in that respect a circuit that can correspond to both the ₁ and f _2. In this example, the frequency conversion from the reception frequency to the transmission frequency is required. The frequency conversion is performed by the reception circuit 2 (reception circuit-I) or the transmission circuit 4 and the reception circuit 2 (reception circuit-I ), There are two methods in which the signal is converted into an IF frequency and then converted by the transmission circuit 4 into a transmission frequency.

FIG. 6 is a schematic diagram showing a fourth embodiment of the self-propagating wireless distribution network according to the present invention. FIG.
Is a configuration of the wireless distribution network shown in FIG. 2, using the wireless device B shown in FIG.
Resend at frequency f ₂ when the frequency of the received radio wave is f _1, the frequency of the received radio waves is obtained so as to re-transmit at the frequency f ₁ when the f _2. First, the base station [outside 1]
8, the identification information "N" indicating that "this radio wave is transmitted from the base station [external 1] 8" is added,
To emit radio waves of frequency f _1. Next, the receiving station [outside 2] 9
Then, a radio wave of the frequency f ₁ from the base station [external 1] 8 is received, and “this radio wave is transmitted to the base station [external 1] 8 and the transmitting station [external 2]”.
"N, so"
By adding, it retransmits a radio wave of the frequency f _2. Further, the receiving station [external 3] 10 receives a radio wave of the frequency f ₁ from the base station [external 1] 8 and “this radio wave is transmitted to the base station [external 1] 8”.
8, the transmitting station is obtained via [External 3] "indicates that the identification information" N, by adding the "re-transmitted in radio waves of the frequency f _2.

The receiving station [outside 4] 11 can receive the radio wave (frequency f ₂ ) of the transmitting station [outside 3] 10.
The identification information "N, sa, ko" indicating that this radio wave has passed through the base station [outside 1] 8, the transmission station [outside 3] and the transmission station [outside 4] is added, re-transmitted in radio waves of frequency f _1. At the receiving station [outside 5] 12, the transmitting station [outside 2]
Since the signal reception (frequency f _2), "the radio waves, the base station [External 1] 8, is obtained by way of the transmission station [External 2] and the transmitting station [External 5]" identification information indicating that "N, its, only" by adding, to re-transmit a radio wave of frequency f _1.

Further, the receiving station [outside 6] 13 can receive radio waves from the transmission station [outside 5], the transmission station [outside 3], and the transmission station [outside 4]. FIG. 6 shows the measured values of the transmitting station identification information, the frequency, the number of transmission stages, and the reception CN ratio of each received radio wave.
Shown in Each of these thresholds of the reception CN ratio (20
Since dB) is satisfied and does not include the identification information of the transmitting station [outside 6], the radio wave of the transmitting station [outside 3] having the smallest number of transmission stages is selected. As a result, the receiving station [outside 6] 13 says, "This radio wave has passed through the base station [outside 1] 8, the transmission station [outside 3], and the transmission station [outside 6]."
Identification information indicating that "N, is, o" by adding and re-transmitted in radio waves of the frequency f _1.

In this case, it is necessary to provide the wireless device (wireless device B (see FIG. 5)) with a frequency conversion function as compared with the case where a single frequency radio wave is retransmitted. Since the number of possible steps can be set large,
Radio waves from the base station [outside 1] 8 can be distributed to a wider area. Even when a plurality of frequencies are used, the wireless distribution network can be configured in a short time by performing retransmission based on predetermined conditions.

A radio apparatus A that performs retransmission at the same frequency (f ₁ ) as the received radio wave as shown in FIG.
Using the two frequencies f _1, f _2, as shown in, the frequency of the received radio wave is retransmitted by the frequency f ₂ when the f _1, the frequency of the received radio wave is retransmitted at the frequency f ₁ when the f ₂ radio Even when the self-propagating wireless distribution network of the present invention is configured in combination with the device B, FIGS.
As in the case shown in FIG. 6, the wireless distribution network can be configured in a short time.

In the above, the number of transmission stages and the reception CN
Although the case where each threshold value of the ratio is constant has been described, these threshold values can be changed and set for each network or each wireless device. As an example, when the number of receivable radio waves is large, the threshold value of the number of transmission stages set in the wireless device is set low. Thus, for example, retransmission can always be performed in an area where there are few receiving stations, such as a suburban area, and retransmission can be limited in an area where there are many receiving stations in an urban area. In this way, by making the setting of the threshold variable, a wireless distribution network can be constructed in a short time according to the use of radio waves in the reception area.

[0035]

According to the present invention, the radio wave to be received is selected based on the identification information of all the transmitting stations through which the received radio wave has passed. There is no choice. In addition, by performing retransmission control based on the identification information of all the transmitting stations through which the received radio wave has passed, the measured value of the received CN ratio, and the preset number of transmission stages and the threshold value of the CN ratio, loop oscillation is achieved. Also, it becomes less susceptible to the rise of the noise level due to the interference wave. As a result, a stable and good wireless distribution network can be constructed in a short time.

According to the present invention, selection of a received radio wave and control of retransmission are performed using information obtained from the received radio wave and a preset threshold value, and the transmission radio wave of the wireless device is received. Information from the receiving station (slave station) is not used. Therefore, since a so-called uplink is not required, the wireless distribution network can be configured at low cost.

Further, according to the present invention, the receiving station performs retransmission in principle, and does not necessarily need to directly receive radio waves from the base station. Therefore, as the number of receiving stations increases, the number of radio waves that can be received increases, and a wireless distribution network can be introduced in a short time and at low cost.

Further, according to the present invention, since the receiving station performs retransmission, a redundant route can be secured.
Even when the reliability of each propagation route is low, the reliability of the entire network is high.

Further, according to the present invention, since the thresholds of the number of transmission stages and the CN ratio can be set for each network or each wireless device, a stable and good wireless communication can be performed according to the use condition of radio waves. A distribution network can be built in a short time.

[Brief description of the drawings]

FIG. 1 comprises a self-propagating wireless distribution network of the present invention together with a base station and other retransmitting wireless devices;
FIG. 3 is a block diagram showing a configuration example of a wireless device A that performs retransmission at the same frequency (f ₁ ) as a received radio wave.

FIG. 2 is a schematic diagram showing a first embodiment of the self-propagating wireless distribution network of the present invention.

FIG. 3 schematically shows a second embodiment of the self-propagating wireless distribution network of the present invention.

FIG. 4 schematically shows a third embodiment of the self-propagating wireless distribution network of the present invention.

[5] Two using frequencies f _1, f _2, radio frequency of the received radio wave is retransmitted by the frequency f ₂ when the f _1, the frequency of the received radio wave is to be re-transmitted at the frequency f ₁ when the f ₂ One configuration example of the device B is shown in a block diagram.

FIG. 6 is a schematic diagram showing a fourth embodiment of the self-propagating wireless distribution network of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 main line system 2 reception circuit-I 3 control unit 4 transmission circuit 5 reception radio wave selection system 6 reception radio wave separation unit 7 reception circuit-II 8 base station 9, 10, 11, 12, 13 reception station

Continuing on the front page (72) Inventor Hiroyuki Furuta 1-10-11 Kinuta, Setagaya-ku, Tokyo Japan Broadcasting Research Institute Inside the Broadcasting Research Institute (72) Inventor Junji Kumada 1-10-11 Kinuta, Setagaya-ku, Tokyo Japan Broadcasting Research Institute Broadcasting Research Institute F-term (reference) DD17 EE13 EE33 GG14 GG27

Claims (3)

[Claims] 1. A self-propagating wireless distribution network comprising a base station and a plurality of receiving stations having a retransmission function, wherein each of the receiving stations constituting the network performs the reception upon retransmission. Means for transmitting the identification information of the transmitting station indicating all the transmitting stations that have passed through to the receiving station, and the identification information of the transmitting station for each radio wave received by the receiving station. Based on a comparison between the measured values of the number of transmission stages and the reception CN ratio, and a preset threshold value of the number of transmission stages and a preset threshold value of the reception CN ratio, the currently received radio wave is transmitted to another A self-propagating wireless distribution network, comprising at least a determining means for determining whether to switch to a received radio wave. 2. The self-propagating wireless distribution network according to claim 1, wherein the determination is that the number of transmission stages is smaller than a threshold value of the preset number of transmission stages.
The measurement is performed on whether the measured value of the reception CN ratio is higher than the preset threshold value of the reception CN ratio and whether the number of transmission stages is the smallest. Self-propagating wireless distribution network. 3. The self-propagating wireless distribution network according to claim 2, wherein, when there are a plurality of transmission stages with the smallest number of transmission stages, the measured value of the reception CN ratio is the highest among them. A self-propagating wireless distribution network characterized by being performed to select ones.