WO1994028641A1

WO1994028641A1 - Method and apparatus for transmitting information

Info

Publication number: WO1994028641A1
Application number: PCT/FI1994/000213
Authority: WO
Inventors: Jouko Rautio
Original assignee: Telecom Finland Oy
Priority date: 1993-05-27
Filing date: 1994-05-27
Publication date: 1994-12-08
Also published as: EP0705502A1; FI932433A0; HUT73124A; NO954732L; CN1124549A; HU9503379D0; FI108382B; HU215895B; EE03327B1; AU6797894A; LV11509A; LV11509B; NO954732D0; FI932433A; JPH08510605A

Abstract

The object of the invention is transmission along a transmission path between a base station (1) and a receiving or transmitting mobile phone (5), when coverage area of the base station is not adequate. This is accomplished such that the radio frequency message is converted within the transmission path at one part (3b, 3a) of a repeater into a message of audio frequency type, which is converted into a message of radio frequency type at a second part (3a, 3b) of the repeater, whereby the mobile phone (5) is capable to receive the same.

Description

METHOD AND APPARATUS FOR TRANSMITTING INFORMATION.

The invention relates to an assembly and method for accomplishing a radio contact between two radio interfaces and transmitting information between these interfaces.

Transmission of information along a radio transmission path, e.g. through an obstacle, like a wall, may sometimes appear to be difficult, because a power of a mobile phone or base station is limited. This problem is illustrated in figure 1. A communication is tried to provide between the mobile phone 5 and base station 1, even the phone is situated behind some obstacle 9, there through the communication is now possible. Nowadays information is transmitted into or from indoors in the way illustrated in the figure 2. Information is transmitted at a radio frequency from a base station 1, BS to an antenna 2 connected to a repeater 3 via a radio frequency cable 4. The repeater 3 is a device, which automatically re-transmits signals from one communication to another. Generally the repeater 3 is indoors in the case like this. The information is amplified in a radio frequency amplifier 6 of the repeater and transmitted to a hand-held telephone 5 indoors. The amplifier 6 is of broad-band type. The input electric power is distrib¬ uted into several channels whereby levels of the calls at the amplifier may change. The cables 4 and 4a from the antennas 2 and 2A to the amplifier must be of radio frequency cable, hence the information transmission by this way is remarkably expensive. The call or another information is transmitted into the opposite direction correspondingly.

In order to solve this problem and to provide information transmission characteristic to the method and assembly according to the invention is that what is presented in the characterising parts of the claims.

As the remarkable benefit of the invention can be considered that the information transmission expenses decreases. Previously known standard circuit boards, which are used in mobile phones, can be used as the devices. Hence the transmitter/receiver cir¬ cuits of the mobile phone, which are normal serial production components, can be benefited. The radio frequency is not necessary to transmit via the radio frequency ca¬ ble through the obstacle. The communication between the upper and lower parts of the repeater is possible to provide more economically than before.

The invention is described referring in the following to the drawing, wherein figure 1 illustrates a principle figure of the field of the problem, figure 2 illustrates information transmission in accordance with the prior art, figure 3 illustrates a solution according to the invention from an embodiment, figure 4 illustrates receiver and transmitter solutions for a message transmitted from a base station.

There is illustrated in the figure 3 an improvement to transmit a radio telephone mes¬ sage, when the message to be transmitted at a radio frequency is desired to transmit to a place which is not accessible by a normal base station use. In the following is de¬ scribed the message transmission into one direction. It is naturally evident that the message transmission into the opposite direction is possible and it is provided in a cor- responding way as into the opposite direction.

A message at a radio frequency is transmitted from a base station 1 (BS) to an antenna 2 of an upper part 3a of a repeater. The upper part 3a of the repeater receives the mes¬ sage at the radio frequency and is capable to convert or demodulate the message away from the radio frequency to an audio frequency, wherein the same is transmitted e.g. via a cable 7 into a transmitter at a lower part 3b of the repeater, a carrier wave is modulated and transmitted from the lower part of the repeater as a radio wave along a transmission path 8 to the hand-held telephone 5.

More precisely the repeater is formed of transmitter and receiver circuits of an NMT- telephone and comprises the upper part (master) and the lower part (slave). For pro¬ tecting these circuits a casing or a corresponding is provided. A central unit controls the communication from the inner part to the outer part and vice versa and it is capable to recognise signalising commands by which the call is directed to receivers and by which the repeater is controlled both is capable to convert a radio frequency to a audio frequency and vice versa.

The transmitting and receiving frequencies of the lower part of the repeater corre¬ sponds to the frequencies of the base station. Although the repeater composed of the transmitter and receiver circuits of the NMT-telephone may lead to a power decreasing when transmitting, in most cases even a low power is adequate, because the spaces in¬ doors are limited.

Because the call is transmitted between the heads of the double sectional by means of audio frequency, the wires to be used are economical. Therefore it is possible that by using a ramifier means from the upper head or the master section of the repeater may extend several wires, the ends thereof are placed different rooms or spaces such, that the message can be transmitted to the desired locations. The solution according to the invention in its simplest mode connects at mobile telephone traffic of frequency dis¬ tributed type only one call at a time. Depending on the number of calls it is possible to choose a system of desired extent. The invention is especially preferred for a low density call connection.

Any copper cable, light cable, radio link or e. g. double wire connection can be used as the transmission path 7 between the upper and lower heads of the repeater. The re¬ peater must be capable to receive messages and to transmit the same further to the transmission path. The method may transmit mobile telephone traffic of time, code or frequency distributed type.

It is possible to make the upper and lover heads of the repeater as module constructed , whereby also at the frequency distributed traffic the calls are possible to connects at several channels.

In the figure 4 there is illustrated in a more precise way a message transmission in one direction from a base station to a mobile telephone. There is naturally a reason to state, that the message is possible to transmit into the opposite direction when reverse cir¬ cuits are in use. The message transmitted from the base station 1 is transmitted, the message is received at an upper head 32 of a repeater by a receiver circuit, the message is converted to be of audio frequency type and the message is guided via the communi¬ cation path 7 between the lower and upper parts 3b, 3a to the transmitter circuit 3b of the lower part of the repeater, while a speech of basic frequency modulates the radio frequency of the radio transmitter 3b the radio waves are transmitted to the receiver 5 of the mobile phone.

Especially there is the reason to notice that the invention is described above referring to only one advantageous embodiment example thereof. However, the same is not in¬ tended by any means to limit the invention to concern just this example but several modifications are possible within the scope of inventive idea defined in the following claims.

Claims

1. Method, in which method information is transmitted between a base station (1) and radio telephone (5) by a repeater (3) along a transmission path, characterized in, that between the base station (1) and the mobile phone (5) a radio frequency message is demodulated into an audio frequency message by a repeater (3a, 3b) existing at the transmission path, which repeater is capable to execute audio/radio frequency conver¬ sions and to transmit information thus converted along the transmission path to the subscriber, and which repeater includes two sections (3a, 3b) having the abobe men- tioned functions and an audio frequency connection (7) therebetween.

2. Method according to the claim 1, characterized in, that the information transferred over a radio interface is received by the repeater (3 a, 3b), which is a radio re¬ ceiver/transmitter unit, the information is demodulated therein from radio frequency, the demodulated information is transmitted along the transmission path (7) as a carrier frequency to another receiver/transmitter unit (3 a, 3b), while speech of basic fre¬ quency is modulating the radio frequency of the radio transmitter (3b, 3a) the radio waves are transmitted to the mobile phone (5).

3. Method according to the claim 1, characterized in, that via the repeater (3 a, 3b) is transmitted frequency distributed information.

4. Method according to the claim 1, characterized in, that via the repeater (3a, 3b) is transmitted time distributed information.

5. Method according to the claim 1, characterized in, that via the repeater (3a, 3b) is transmitted code distributed information.

6. Method according to the claim 1, characterized in, that transmitting and receiving frequencies of the inner part (3b) of the repeater corresponds to the frequencies of the base station (1).

7. An assembly for transmitting information between a base station (1) and mobile phone (5) by a repeater (3) along a transmission path, characterized in, that there ex- ist between the base station (1) and the mobile phone (5) a radio frequency message to an audio frequency message and an audio frequency message to a radio frequency message converting repeater (3 a, 3b), which is capable to execute the audio/radio fre¬ quency conversions and to transmit information thus converted along the transmission path to the subscriber, and which repeater includes two sections (3a, 3b) having the abobe mentioned functions and an audio frequency connection (7) therebetween.

8. An assembly according to the claim 8, characterized in, that the audio frequency connection is a radio link, copper or light cable or a couble of wires.