JP3292769B2 - Communication method between mobile stations - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital cordless telephone terminal, and more particularly, to a digital cordless telephone terminal capable of searching for a communication channel of a digital cordless telephone capable of making a direct call between slave units.

[0002]

2. Description of the Related Art A method of searching for a communication channel for direct communication between slave units described in a second generation cordless telephone system standard (draft) will be described below. A digital cordless telephone terminal (PS: Personal)
Stations can communicate with each other at the same private base station (C
(S: Cell Station) and are limited to PSs (the system call codes recognized by the PSs are the same).

FIG. 2 is an explanatory diagram of a control sequence for direct communication between slave units described in the second generation cordless telephone system standard (draft). Originating PS (PS calling the other party PS to make a call directly between the handset) in order to detect an empty slot direct communication carrier between handset, performs carrier sense the required standards (draft) is determined, After confirming that the carrier is available (vacant), the call signal a is transmitted to the other party who wants to talk at the slot timing of the carrier. On the other hand, when the receiving side PS (the PS receiving a call from another PS) is in a call waiting state of the direct communication between the slaves, the calling signal to the own station is transmitted by sequentially searching for the carrier for the direct communication between the slaves. Look for not.

[0004] The receiving side PS has its own PS calling number and the PS
After receiving the paging signal a containing the same system paging code as the registered CS, a synchronization signal b is transmitted to the originating PS at a slot timing 2.5 ms after the reception of the paging signal. Then, the synchronization signal b from the receiving side PS
The transmitting side PS that has received the synchronization signal c transmits the synchronization signal c. The receiving PS receiving the synchronization signal c from the calling PS transmits a response signal d when the user presses the response button.
After that, a TCH (Traffic Channel) idle burst signal e, f is exchanged to perform a call operation.

[0005]

As a carrier (frequency) for direct communication between slave units, a total of 10 waves can be used.
In the receiving side PS, in the call waiting state of the direct communication between the slave units, the calling side PS cannot recognize in advance which carrier and which slot timing the calling signal is transmitting to the own station. Therefore, in order to search for a call signal in a carrier for direct communication between slave units, it is necessary to perform a search operation while switching the frequency for direct communication between slave units. In the case where the called PS searches the calling signal by switching the frequency for each frame, as shown in FIG. 3, the frequency (carrier 1) at which the calling PS is transmitting the calling signal and the calling PS are determined. Even if the frequency (carrier 1) in which the paging signal is searched is the same, since the PSs are asynchronous with each other, the receiving PS
In paging signal search period is the next frequency (carrier 2)
If the paging signal is sent immediately before switching to, the carrier 1 may not be able to receive all the paging signals. Further, when the calling signal is searched by switching the frequency every two or more frames, the above-described problem does not occur, but there is a disadvantage that the search takes time.

Conventionally, the number of carriers used in a direct telephone call between slave units is previously fixed in a digital cordless telephone terminal. Since the search was performed, there was a drawback that there was much waste in terms of power consumption and the use time was shortened.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and in a digital cordless telephone terminal having a direct communication function between handset units, the frequency is switched every frame + 1 slot at the time of calling signal search, and the used carrier is searched. It is an object of the present invention to provide a digital cordless telephone terminal in which a search time is reduced and power consumption is suppressed by setting the number.

[0008]

According to the present invention, in order to achieve the above object, (1) a mobile station on a transmitting side has a predetermined frequency.
An empty slot is detected from the band, and the empty slot is
The timing of the empty slot in the detected frequency band
The paging signal is transmitted by paging while the receiving mobile station
Search for a predetermined frequency band in sequence and call
When a signal is detected, communication with the transmitting side mobile station is performed.
In the direct communication method between mobile stations to be started,
The frequency band searched by the mobile station is 1 frame + 1 slot
Switching every time , and (2) between the mobile stations
In a direct communication method, the transmitting mobile station and the receiving
Frequency band used for direct communication between mobile stations at the receiving mobile station
Should be set to less than the available frequency band.
It is characterized by the following.

[0009]

The present invention reduces the time required for the calling PS to search for a call signal to be transmitted in order to perform a direct telephone call between subunits when the receiving side PS is in a call waiting state for direct telephone communication between subunits. In the receiving side PS, the own timing is used, and one frame + 1 slot time (5.625 ms)
c) By sequentially switching the frequency to be searched for each time, it is possible to reduce the time required to search all the carriers for direct communication between slave units and to perform the search reliably. Also,
By selecting the number of carriers for direct communication between subunits to be used in a PS that intends to perform direct communication between subunits, the time required for searching for carriers for direct communication between subunits is reduced, and the battery is effectively reduced. You can save.

[0010]

Embodiments will be described below with reference to the drawings. FIG. 1 is an explanatory diagram for explaining an embodiment of a digital cordless telephone terminal according to the present invention, and is a diagram showing a case where frequency switching is performed for each frame + 1 slot. First, the number of carriers for direct telephone communication between handset units used between digital cordless telephone terminals (PS: Personal Stations) attempting direct telephone communication between handset units is set, and the originating PS detects carrier sense using the set carrier. Perform a search for a carrier for transmitting the calling signal. Also,
The receiving side PS searches for a call signal on the set carrier. Here, the frequency to be uniquely used is determined by setting the number of carriers.

In FIG. 2 described above, the transmitting side PS (the P.S.
S) performs carrier sense defined by this standard (draft) in order to detect an empty slot of a carrier for direct communication between slave units. After confirming that a certain slot of the frequency at which carrier sensing has been performed is available (empty), the receiving side PS (other PS) is used at the slot timing of that carrier.
A call signal a is transmitted to the PS that receives a call from.

On the other hand, in the receiving side PS, in a call waiting state of the direct communication between the handset units, by searching the carrier for the direct call between the handset units for a certain period of time, it is determined whether or not the calling signal to the own station is transmitted. Search. At this time, one frame +
By switching the frequency for each slot and searching for the calling signal, the search can be reliably performed. As a result of the search for a certain period of time, the receiving side PS includes its own PS in the received signal.
When a calling signal a containing a calling number is received, a synchronization signal b is transmitted to the calling side PS. The transmission is performed at a slot timing 2.5 ms after the call signal a from the calling side PS is received.

Thereafter, in accordance with the sequence shown in FIG. 2, the transmitting PS receiving the synchronization signal b from the receiving PS.
Transmits the synchronization signal c and transmits the synchronization signal c from the transmitting side PS.
Is received, the user presses a response button to transmit a response signal d, and then exchanges TCH idle burst signals e and f to perform a call operation.

As described above, the digital cordless telephone terminal according to the present invention provides a mobile station (P) having an operation function based on the second generation cordless telephone system standard (draft).
S: Personal Station (PS) registered in the same private base station (CS: Cell Station)
PS that has two systems of frequency setting devices (PLLs) in order to enable PSs to talk directly without going through
, A switching means for sequentially switching the frequency is provided, and in order to shorten the time required for the calling PS to search for a call signal to be transmitted in order to perform a direct telephone call between the slaves, the receiving PS uses its own timing for one frame. Search every +1 slot time (5.625msec). As a result, the time required to search for all of the direct communication carriers between slave units is reduced, and the search is performed reliably.

[0015] Also, a PS for making a direct call between slave units.
In the above, by providing a setting means for setting the number of direct communication carriers between slave units to be used, for example, when it is considered that other direct communication carriers between slave units are often used, the use of PS If the number of carriers is set to be large, and if it is considered that the carrier for direct communication between slave units is not used much, the number of used carriers of the PS is set to be smaller, so that the Shorten the time required to search for a direct call carrier and save battery effectively.

[0016]

As is apparent from the above description, the present invention has the following effects. (1) When the calling PS transmits a calling signal after performing carrier sense, the time for switching the frequency for searching for the calling signal in the called PS is set to 1 frame + 1 slot, The time required to search for a call signal for the own station can be reduced. (2) Further, by having a function of setting the number of carriers to be used depending on the situation where direct communication between slave units is used, the time required for carrier sense of the calling PS and the calling signal of the called PS to the own station can be reduced. The search time can be shortened, and the effect of reducing power consumption can be expected.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram for explaining an embodiment of a digital cordless telephone terminal according to the present invention.

FIG. 2 is an explanatory diagram of a control sequence of direct communication between slave units described in a second generation cordless telephone system standard (draft).

FIG. 3 is a diagram for explaining a case where frequency switching in a conventional digital cordless telephone terminal is performed for each frame.

────────────────────────────────────────────────── (5) References JP-A-57-145448 (JP, A) JP-A-63-19926 (JP, A) JP-A-4-213933 (JP, A) "Second generation cordless" Telephone system standard RCR STD-28 "p. 423 (Chapter 6 Direct communication between slave units), first edition formulated on December 20, 1993, The Association of Radio Industries and Businesses (58) Fields surveyed (Int. Cl. ⁷ , DB name) H04B 7/26 H04Q 7/00

Claims (2)

(57) [Claims] 1. A transmission side mobile station in a predetermined frequency band.
Empty slot is detected from the
At the timing of the empty slot in the allocated frequency band.
While transmitting the paging signal, the receiving mobile station
Search in the frequency band of
Start communication with the transmitting mobile station when detected
In the direct communication method between mobile stations, in the receiving mobile station,
The frequency band to be searched is set every frame + 1 slot time
A direct communication method between mobile stations, characterized by switching . 2. The transmitting side mobile station and the receiving side mobile station.
The station uses the frequency band used for direct communication between mobile stations.
2. The direct communication method between mobile stations according to claim 1, wherein the frequency band is set to be smaller than a frequency band that has been enabled .