DE9214887U1 - Arrangement for controlling a transceiver - Google Patents

Description

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Siemens AG

Arrangement for controlling a transmitting/receiving device 5

The invention relates to an arrangement for controlling a transmitting/receiving device, in particular the transmitting and receiving device of a base station and/or a mobile part of a cordless telephone system according to the preamble of claim 1.

The German Federal Post Office's FTZ guideline 1TR2, part 3.2 from April 1990 already specifies rules for the operation of cordless telephones. In connection with the operation of a radio connection (call initiation procedure), a channel search is provided, in which, in the operating state, the receivers of the fixed station and portable system constantly search for HF signals with a specific identifier on the channels assigned to them. The search time (initialization to loop formation or vice versa) is specified.

Based on this prior art, the invention is based on the object of specifying an arrangement of the type mentioned at the outset which simplifies the procedures in connection with channel searching.

It is essential for the invention that the channel search preferably takes place on channels that are identically defined for the base station and the associated mobile units. This significantly shortens the channel search time on average; the number of unsuccessful attempts to use channels is reduced and the energy required for these procedures is saved. This applies to both the base station and the mobile unit(s).

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In a further advantageous embodiment of the invention, it is provided that the channels controlled during the channel search are determined depending on an identification code assigned to the base station and the mobile part. This further shortens the channel search time if several groups of base stations and mobile parts are each controlled in a corresponding manner.

The invention will now be described with reference to the figure, which shows a block diagram of a transmitting/receiving device according to the invention.

The receiving device shown in Fig. 1 is formed, for example, by the base station FT of a cordless telephone. The following description assumes that the DECT standard is implemented for the cordless telephone. However, the invention is not limited to this. The receiving device consists of a receiving part with two receiving antennas Al and A2. In addition, a transmitting device can be provided in connection with the receiving device. The transmitting device is also connected to the antennas Al and A2, which in this case also function as transmitting antennas. The transmitting/receiving device is designated "TRANSC" in the figure.

Firstly, a switching element ADS (Antenna Diversity Switch) is integrated into the transmitting/receiving part TRANSC, which is controlled by control data CDATA, which a processor DECT-C - as will be described later - forms and, for example, feeds to the transmitting/receiving device TRANSC via a multiplex/demultiplex unit MUL/DEM.

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A programmable microprocessor or a hardware structure can be used as the DEC-T processor, which, for example, has latches for temporarily storing the field strength and/or threshold values and comparators for comparing different values. In the following, DEC-T refers to both designs.

This TRANSC device also has an RSSI-C device integrated, which measures the field strength of received signals. This RSSI-C device is generally used to check whether a channel is occupied. A channel is considered free if the field strength is less than 20 dB; it is considered occupied if the field strength is greater than or equal to 20 dB. The regulation on how the field strength is to be measured is specified in the DECT standard. Channel occupancy is determined by measuring the field strength (minimum field strength) of received signals. The RSSI-C unit measures the field strength of received signals, with the measurement results being fed to the DECT-C processor via an analog/digital converter A/D and used by the processor to generate the control data CDATA and to control the threshold generator TH-G integrated in the DECT-C processor. The threshold value generator TH-G continuously generates updated values during operation, whereby a different (higher or lower) or the same value is generated compared to an existing value. The threshold values are generated depending on the field strength values (RSSI) measured in successive periods of time with the help of the RSSI-C unit and the DECT-C processor.

The multiplex/demultiplex unit MUL/DEM generates or receives, for example, 1.152 Mbit/s data in DECT burst format and assigns received or to-be-sent data

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packets, for example, up to six internal or three external telephone connections using the time division multiple access (TDMA) method.

The MUL/DEM device has integrated coding and decoding devices ADPCM, which are followed by internal subscriber circuits or exchange or private branch exchange circuits. These devices, which are connected downstream of the MUL/DEM device, form a telephone part TFT, which can be constructed in the same way as the telephone line parts of known cordless telephone systems (Wolf, Klaus: "Auch ohne Schnur "auf Draht"", telcom report 10, 1987), issue 2, pages 130 ff. (134).

If the arrangement shown in the figure represents a handset PT of a cordless telephone with several antennas, the functional block TFT can be formed by the components that work in the handset independently of the method according to the invention (see "Microphone, batteries, identification contact, LED display, 4x5 keypad, flap switch, ringer, earpiece", telcom report IO (1987), issue 2, page 135).

The base station FT can be assigned several, e.g. 4, base station-specific mobile parts PTL..PTn. A base station and the base station-specific mobile parts assigned to it form a group. The group is assigned an identification code by the device manufacturer.

The base station and the mobile units each have a processor to which a control program designed in such a way is assigned that the base station and the associated mobile units, when not in use, search the frequency channels allocated to them, e.g. K1...K80, for high-frequency signals with an identification code intended for them.

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chen. When there is an incoming or outgoing connection, a free frequency channel is occupied. The channel search always starts on a specific channel, a so-called preferred channel, and if this channel is not occupied, it continues on other matching channels. For example, the channel search starts on channel 46 and, if unsuccessful, continues on channel 53 and, if unsuccessful, on channels 60, 67, etc.

The channels addressed during the channel search are determined depending on the identification code assigned to the base station and the mobile units assigned to it (group identification code).

In cordless telephone systems in which transmissions take place on certain frequencies and in predetermined time slots, the channel search is also carried out depending on an identification code that is assigned to a base station and the handsets assigned to it.

In idle mode, the base stations of all systems transmit a radio beacon at a predefined rhythm, the frequency and timing of which are changed cyclically at a predefined time interval. The handsets have the option of using the transmitted data to identify their assigned base station and to log in and synchronize with it.

In order to prevent all base stations from starting on the same frequency and at the same time after a power failure and interfering with one another in an environment where the ranges of the base stations overlap, the start frequency and time are derived from the serial number (identification code) of the base station.

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The ID is derived from the serial number of the device and is entered by the manufacturer into the memory of the base station. This ID number is stored, for example, as a five-digit hexadecimal value.

Example serial number: 845321
ID: CE609H.

Signaling numbers are used for signaling to and from a handset, which are managed by the base station during registration and deregistration.

The so-called preferred channels (Pr) mentioned above are the channels with which the channel search begins.

The preferred channels are derived from the identifier (ID). The last seven bits of the identifier number are used as the basis for calculation. For example, ID: 3F6AEH

KVl: 2EH = 46

KVn: 2EH+(nx7).
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Claims (2)

G U \ 9 EN 7 Protection claims 1. Arrangement for controlling a transmitting/receiving device, in particular the transmitting and receiving device a base station and/or a handset of a cordless telephone system, in which each base station (FT)
&eegr; (n=l...eg 4) base station-specific handsets (PTl ...PTn) are assigned, whereby a base station (FT) and
a mobile part (PT) each have a processor (DECT-T) to which a control program designed in such a way is assigned, that the base station (FT) and the associated handsets
(PT) when not in use, search the frequency channels allocated to them (K1...K80) for high frequency signals with an identification code (ID FT, ID PTl,...ID PTn)
and a free frequency channel for an incoming or
outgoing connection,
characterized,
that the program assigned to the processor (CC) continues is designed in such a way that the channel search is started consistently at a certain channel (KV, e.g. 46) and in case of non-occupancy of this channel (KV) the
Channel search continues on other matching channels (53,60,...). 2. Arrangement according to claim 1,
characterized, that the channels (46, 53, 60,...) controlled during the channel search are determined depending on an identification code that is assigned to the base station and the mobile units assigned to it.