JPH04255123A - Digital cordless telephone connection method - Google Patents

Abstract

PURPOSE:To reduce the time from a line connection request to an actual calling by allocating plural channels (Ch), Using one of the plural channels as a notice channel commanding a control channel and using the notice channel by each base station. CONSTITUTION:A notice channel A in plural channels (Ch) is divided into notice bursts 21-2n by a number of base stations for discriminating a base station repeated for a prescribed period. When a slave set makes a line connection request, the slave set receives the channel A and detects a burst with a strongest electric field strength among the bursts 21-2n to decode a control channel code 2d or the like. Then the slave set communicates with a base station through a talking channel by using various sets of information such as individual or simultaneous call between a base station and the slave set, identification of the slave set and an idle channel through a control channel B received by the designation of a code 2d by way of a speech channel. Thus, a nearby base station is caught and the time from the line connection request to the actual call is reduced.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telephone connection method for a digital cordless telephone.

0002

2. Description of the Related Art Digital cordless telephones such as telepoint systems generally use the TDD method as a wireless transmission/reception method between a base station and a handset. In the TDD method, a radio wave of a certain frequency, that is, a communication channel, is divided into predetermined periods, and each period is alternately occupied as a transmission slot T and a reception slot R, thereby performing so-called ping-pong transmission.

[0003] Conventionally, the line connection method for this type of digital cordless telephone has been performed in accordance with the following procedure. This will be explained below with reference to FIG. First, each of the base stations BS1 and BS2 independently transmits within the service area a control channel f1 in which an identification code indicating each base station is repeatedly inserted. In this state, when the user makes a line connection request (dialing) using the handset MS1, the handset MS1 receives the control channel f1 and searches for the nearest base station. In other words, the slave MS
1 is only in the service area of one base station BS1, the control channel f1 from that base station BS1
Only that base station BS1 can receive the data, and the line with that base station BS1 is connected. If the handset MS1 is located across the service areas of a plurality of base stations BS1 and BS2, it selects the control channel with the strongest electric field strength and connects the line with that base station.

[0004] When the line is connected, the handset is switched to a mode that uses a communication channel, and a calling signal is transmitted. Therefore, the calling signal is sent to an exchange (not shown) via line L, making it possible to send and receive voice signals.

[0005]

[Problem to be Solved by the Invention] However, in the conventional digital cordless telephone connection method, in order for the handset to detect the nearest base station, it must receive the control channels of all expected base stations, and The base station was identified based on the control channel with the strongest electric field strength. For this reason, it takes time to acquire the control channel, which makes the user feel that there is a considerable waiting time between operating the handset and making a call.

[0006]

[Means for Solving the Problems] The present invention is a digital cordless telephone connection method for transmitting and receiving data between a plurality of base stations and a plurality of handsets, which allocates a plurality of channels and One of the channels is used as a broadcast channel for instructing at least a control channel, and this broadcast channel is shared by each base station.

[0007]

[Embodiment] Fig. 1 shows an example of the configuration of a handset to which the present invention is applied, in which 1 is an antenna, 2 is a transmission/reception switch, 3 is a radio reception section, 4 is a demodulation section, and 5 is a radio transmission section. ,
6 is a modulation section, 7 is a communication control section, 8 is an audio encoding/decoding section, 9 is a speaker, 10 is a microphone, and 11 is a key input operation section.

[0008] The communication control section 7 controls switching of the used channel to a control channel or a communication channel, and controls transmission and communication.
Performs reception switching control, etc. For example, when making a call or receiving a call, it receives key inputs from the key input operation section 11 and outputs from the demodulating section 4, and sends various command signals to the receiving and receiving parties. 5 and the transmission/reception changeover switch 2 to perform call origination control and incoming call control. Furthermore, in order to determine the timing of transmission and reception, the transmitting slot T and receiving slot R are set.

[0009] When the call state is established, the communication control unit:
The switch 2, the receiving section 3, and the transmitting section 4 are controlled in synchronization with the set transmitting slot T and receiving slot R. Therefore,
Microphone 1 encoded by audio encoding/decoding section 8
The audio signal from 0 is transmitted to the other party via the communication control section 7, modulation section 6, transmission section 5, switch 2, and antenna 1 in sequence at the transmission frequency f1 during the transmission slot T period. In addition, a received signal transmitted from the other party at frequency f1 during the period of reception slot R is received by antenna 1, and is audio encoded and decoded via switch 2, reception section 3, demodulation section 4, and communication control section 7. The encoder 8 decodes the audio signal, reproduces the audio signal, and supplies it to the speaker 9.

The communication control section 7 is constituted by a microcomputer, and the operation of the slave unit is controlled by a program written in a ROM (not shown) or the like. FIG. 2 shows an example of the signal pattern of each channel according to the present invention. A indicates a broadcast channel pattern that is constantly transmitted from each base station. This broadcast channel A is frequency synchronized between each base station. Specifically, this can be easily realized by operating each base station in synchronization with a high-speed telephone network such as ISDN. Therefore, within the service area of any one of the base stations, the handset will receive the broadcast channels transmitted by a plurality of base stations in a mixed state.

Furthermore, this broadcast channel A is divided into units called broadcast bursts 21 to 2n for identifying base stations. These broadcast bursts 21 to 2n exist for the maximum number of base stations during a predetermined period, and are repeated at a predetermined period. This period will be longer if the maximum number of base stations is large, but since the amount of information in one broadcast burst 21 to 2n is small,
The repetition period is extremely short.

[0012] Regarding the broadcast bursts 21 to 2n, one broadcast burst is transmitted at different timings for each base station, and as a result, a plurality of broadcast bursts are superimposed on the broadcast channel. Therefore, regarding the electric field strength of the broadcast channel, the broadcast burst transmitted from the nearest base station is received most strongly, and the broadcast burst from a distant base station outside the service area is received weakly.

[0013] The broadcast bursts 21 to 2n are composed of data for identifying each base station. Specifically, the configuration of each notification burst 21 to 2n is shown in a. That is, preamble 2a, sync word 2b, operator code 2
c, and a control channel code 2d. Preamble 2a is used for synchronization establishment and frequency tracking, and sync word 2b is a synchronization signal. The operator code 2c is a code for identifying a plurality of carriers when they provide services using the same method. 16 operators can be identified with 4 bits. The control channel code 2d is a code for instructing a control channel. It is possible to specify 255 channels with 8 bits. Normally, redundant bits are added to these codes to prevent malfunctions.

Furthermore, this control channel code 2d includes:
A code is assigned to identify that all lines of the selected base station are in use, that is, they are busy. For example, if all bits are "0", it is defined as busy. B and C indicate control channels of each base station according to the TDD method described above. In this example, the slot switching timing of the control channel is synchronized with the broadcast burst of the broadcast channel. That is, B indicates the control channel of base station BS1, and C indicates the control channel of base station BS2. Each of these control channels is alternately assigned a transmission slot T and a reception slot R in synchronization with the start point of the preamble 2a of the broadcast bursts 21 to 2n of the broadcast channel A.

The digital cordless telephone connection method of the present invention configured as described above operates as follows. First, when a user requests a line connection using a slave unit, the slave unit receives broadcast channel A. As mentioned above, the broadcast channel A has a plurality of broadcast bursts 21 to 2n, and among these, the broadcast burst with the strongest electric field strength is detected, and the code of the broadcast burst is decoded. That is, the operator code 2c and control channel code 2d are detected, and it is detected whether the slave device is a contracted operator or not and which channel is assigned to the control channel.

As mentioned above, if all of the base station lines or communication channels are in use or if a communication channel cannot be used due to a line failure, etc., the control channel code 2d contains a code indicating busy (for example, all 0s). exists, so the handset functions to select the next notification burst with the strongest electric field strength. Or notify the user that it is unusable.

Next, the slave unit receives control channel B designated by control channel code 2d. This control channel B includes control information such as a base station code, individual or simultaneous paging information, and the like from the base station to the handsets. In addition, from the handset to the base station, the identification information of the handset,
Free channel information etc. are transmitted. Therefore, it is possible to have a conversation between the handset and the base station via the communication channel using, for example, the above-mentioned TDD method.

Furthermore, in the present invention, conventional speech channels and control channels are treated equally. That is, a certain frequency is normally used as a control channel, but when the communication channel becomes full due to usage, this control channel is also diverted to the communication channel. In this state, the control channel code 2d indicates busy.

[0019] When one of the handsets finishes using the communication channel, the base station transfers the communication channel that has finished being used.
This time, use the notification channel to declare that it will be used as a control channel. That is, a code indicating this frequency is displayed in the control channel code 2d. Therefore, in response to subsequent connection requests from slave devices, the base station specifies the communication channel via this control channel.

[0020]

According to the digital cordless telephone connection method of the present invention, the handset can acquire the nearest base station by receiving only a broadcast channel of a single frequency. Therefore, there is no need to switch between multiple frequencies for reception in order to acquire a base station, and the time from the line connection request to the actual call origination can be shortened.

[0021] Also, when the call channel is full,
Since the control channel is used as a speech channel, the assigned channel can be used to its fullest extent.

[Brief explanation of the drawing]

[Fig. 1] An example of the configuration of a slave device to which the present invention is applied.

[Figure 2]
An example of the signal pattern of each channel according to the present invention

[Figure 3] Conceptual diagram of a communication method for understanding the present invention

[Explanation of symbols]

2 Transmission/reception switching switch 3 Radio receiving section 4 Demodulating section 5 Radio transmitting section 6 Modulating section 7 Communication control section 8 Audio encoding/decoding section A Examples of broadcast channel patterns B, C
Control channel pattern example BS1, BS2 Base stations MS1, MS2, MS3 Slave units

Claims (1)

[Claims] Claim 1: A digital cordless telephone connection method for transmitting and receiving data between a plurality of base stations and a plurality of handsets, the method comprising: allocating a plurality of channels; and controlling at least one of the plurality of channels. A digital cordless telephone connection method characterized in that the broadcast channel is used as a broadcast channel for indicating a channel, and the broadcast channel is shared by each base station.