GB2332121A

GB2332121A - Two way radio communication system, radio unit and method of operation

Info

Publication number: GB2332121A
Application number: GB9725739A
Authority: GB
Inventors: Jens Kristiansen
Original assignee: Motorola AS
Current assignee: Motorola Solutions Danmark AS
Priority date: 1997-12-05
Filing date: 1997-12-05
Publication date: 1999-06-09
Also published as: GB9725739D0; GB2332121A9

Abstract

A radio unit (10, 12, 14, 22, 24, 26, 28, 30, 32, Figs 1 and 2) for operation in a two way radio communication system (20) is provided. The radio unit communicates via at least one resource (34, 36) and includes a voice logger 45, 46 for recording voice information of at least one communication resource by at least one first radio unit. The voice logging operation includes recording the voice transmissions or reception in a memory element 46. The stored voice transmissions can be transmitted to a central unit.

Description

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1 2332121 TWO WAY RADIO COMMUNICATION SYSTEM, RADIO UNIT AND METHOD OF OPERATION Field of the Invention

This invention relates to two-way point-to-point radio communication systems. The invention is applicable to, but not limited to methods of recording voice conversations between at least two radio subscribers in a two-way radio system.

BaCkgmund of the Invention In a two way radio communication system there are often a number of communication resources, for example frequencies, time periods, coding schemes, that are available for allocating to communication system user's to enable the users to set up a communication link. In some communication systems, the radio users transmit and receive on the same radio frequency. In such a system, assuming no geographical reuse of the frequency, only one call can be established between at least two radio units at any one time. It is possible, and often implemented in multi-site systems, that the same communication resources are re-allocated on a geographical basis to some users as long as they do not interfere with existing users using that particular resource, for example where any potential interfering signal level from new users would be too low to be detected by the existing users.

In two-way radio communications systems, coirnmilni cation between two radios is typically performed via individual cafis between two users or via group calls where users communicate to a number of other users in a particular communication group. In mobile trunked radio communication systems, the recording or logging of voice communications is carried out at a central location of the system, for example a central controller or primary base station. A central location is the optimal position for performing voice recording as all voice communications pass through such a position. An example of the necessity for logging voice communications is found in Public Safety Systems where a record of say, a police operation is logged. The information stored in such a process includes the step by step record of ?M 11 2 actual voice communication including what information was provided, at what time, who was involved, etc.

Furthermore, in such communication systems, the registration of used talk time for a subscriber radio leads to the opportunity for the service 5 provider to bill according to the resource voice within the system. In a Groupe Speciale Mobile (GSM) cellular communication system, a record of phone call times is logged at the central station, as communications pass through the central station, which is subsequently used for billing purposes.

In a time division multiple access (TDMA) communication system time and frequency resources are allocated to users in trunked and/or nontrunked commilni cations, for example where each frequency includes four time slots for use by four separate users. In trunked communication systems, use of the communications resource can be monitored and billed for by the service provider, by way of monitoring at the central stations cornmimi cations that pass through. This is often a lucrative business, once the infrastructure and the frequencies have been purchased. In nontrunked operation, i.e. direct mode operation (DMO) in the European TETRA standard, the radio units may communicate on a particular time slot dedicated for this mode of operation. However, there is no central element in this type of communication for either monitoring the use made of the resource by radio units or for recording voice communications.

This invention seeks to provide a two-way communication system, a radio unit for use in the two-way communication system and methods of operating the two way communication system and radio unit which mitigate at least some of the above mentioned disadvantages.

Summary of the Invention

According to a first aspect of the invention there is provided a two way radio communication system. The two way radio communication system includes a plurality of radio units communicating via at least one 35 communication resource. At least one radio unit of the plurality of radio 3 units comprises a voice logger for recording voice information of the at least one communication resource by the at least one first radio unit.

In the preferred embodiment of the invention, the voice logger includes either a time recording fimction for monitoring the time voice of the at least one communication resource by the at least one first radio unit and/or a voice recording function.

In this manner, the voice made of the available communications by the at least one radio unit can be monitored, and the voice communications can be stored and either retained locally in the radio unit and/or relayed to a central control unit at a later date, for example as would be useful in Police radio situations where transmissions may be required for evidence purposes in legal proceedings.

Preferably, the radio unit includes a receiver for receiving voice transmissions on the two way radio communication system, the voice logger includes a voice decoding element operably coupled to the receiver and a memory element for storing said voice transmissions after they have been received and decoded. The voice logger records voice transmissions between the at least one first radio unit and any other radio unit of the plurality of radio units and is capable of transmitting the stored voice transmissions to a central unit over the air or via a fixed communication link. In the preferred embodiment of the invention, the voice logger can be selectively enabled according to the present voice of the two way radio communication system.

In a second aspect of the present invention a first radio unit for use in a two way radio communication system, as hereinbefore described, is provided.

In a third aspect of the present invention a method of operating a radio unit in a two way communication system, as hereinbefore described, is provided.

A preferred embodiment of the invention will now be described by way of example only, with reference to the drawing.

7 1 4 Brief Description of the Dra _

FIG. 1 shows a first two way communication system according to a preferred embodiment of the invention.

FIG. 2 shows a second two way communication system according to a preferred embodiment of the invention.

FIG. 3 shows a block diagram of a at least one first radio unit according to a preferred embodiment of the invention.

FIG. 4 is a flow chart showing a method of operating a at least one first radio unit in the two way communication system according to a preferred embodiment of the invention.

Detailed Description of the Drawings

Referring first to FIG. 1, a two-way radio communications system is shown. Communications are typically performed via individual calls between two remote mobilelportable users or alternatively via group calls where users communicate to a number of other users in a particular communication group, as highlighted in FIG. 1 with communication group 14 containing portable radios 10, 12 and 16. Portable radio unit 10 has entered into communication on a frequency resource with portable radio unit 12, whilst portable radio unit 16 has entered into a commimi on with a fixed portable radio unit 18. It should be noted that the fixed portable radio unit 18 may be any fixed radio unit on the communications system.

Referring now to FIG. 2, a two way communication system 20 is shown that includes a plurality of at least one first radio units, for example mobile stations 22, 24, 26, 28, 30 and 32. In such two way radio communication systems, the mobile stations can be arranged in groups, for example mobile stations 22 and 24 are members of a first group, mobile stations 32 and 30 are members of a second group and mobile stations 36 and 38 are members of a third group. In the preferred embodiment of the invention, the two way communication system 20 has a plurality of communication resources including radio frequencies 34 and 36, each having respective time slots (not shown) arranged in a Time Division 1 Multiple Access (TDAIA) manner. However, it is within the contemplation of the invention that other communication schemes, such as Frequency Division Multiple Access (FDMA) or Code Division Multiple Access (CDMA) would also benefit from the present invention. A communication between mobile radio 26 and mobile radio 28 is being monitored as shown.

The communication begins at a first time period 19 followed by alternating transmissions by each mobile radio before the communication is terminated at time period 21. The total duration 23 of the communication is recorded. It is within the contemplation of the invention that each mobile/portable radio unit monitors at least one time factor of a communication, such as day/date, call start time, call end time, call duration, duration of transmissions by that particular mobile/portable radio unit, total duration of a number of calls by that particular mobile/portable radio unit.

Referring now to FIG. 3, a block diagram of a mobile station 22, 24, 26, 28, 30 or 32 of FIG. 2 is shown. Preferably all mobile stations of the two way communi cation system 20 monitor the transmissions each mobile station makes on either of the radio frequencies 34, 36. Each mobile station includes monitoring means 44 for monitoring the transmission activities on the radio frequency 34 or 36. An antenna 43 is connected to an antenna switch 49, for transferring received signals to a receiver block 48. A second position of the antenna switch 49 connects the antenna 43 to a transmitter block 47. The monitoring means 44 is connected to the receiver block 48 and to the processor 42. The processor 42 contains a timer 41 and is connected to the transmitter block 47 and to a memory element 46. The memory element 46, which may include the function of the processor 42, contains a list 45 of radio frequency transmissions. Processor 42 is also operably coupled to a speech coder for encoding and decoding speech signals to be transmitted from, or received by, the radio unit.

In a first operation of the radio unit, a communication between mobile radio 26 and mobile radio 28 is monitored by monitoring means 44.

The monitoring means 44 monitors here a call is initiated and passes this information to the processor 42. The processor 42, with a time stamp provided by the timer 41, then records timing information of that call to the r--,\ 6 list 45 in the memory element 46. This information may include: other party calling ID, day/date, call start time, call end time, call duration, duration of transmissions by that particular mobile/portable radio unit, total duration of a number of calls by that particular mobile/portable radio unit.

In a second, perhaps alternative, operation of the radio unit, voice communication between mobile radio 26 and mobile radio 28 is recorded by memory element 46. The memory element 46 records transmitted voice signals and/or received voice signals, as provided by the encoding or decoding operation of the speech coder. Such information may be stored with a time stamp, as provided by the timer 41. In the TETRA system, such recording of voice communications can be readily performed as the voice information is often in compressed form. This allows a large number of voice transmissions to be recorded in a limited memory space. Preferably, the voice recording is linked in with a Voice Activation Detection system, either in the transmit and/or receive path, to further limit the amount of voice communication to be stored. Once stored, the recorded voice information can then be transferred to some fixed point, by means of a wireline connection or via over-the-air transmission, as shown in FIG. 1 with the communication between radio unit 16 and radio unit 18.

An over-the-air transmission download of recorded voice transmissions, or time voice, may be implemented whenever the communication system is lightly loaded with regard to traffic communication and the radio unit is within communication range of the fixed unit. This invention also offers the service provider to charge different rates for voice of the communication resource during different time periods or say, on week-ends. Such an opportunity to bill, and bill at different rates, greatly assists the service provider in regulating and controlling the use of the resource.

It is within the contemplation of the invention that other radio ftmction arrangements can be used to provide a similar voice logging function. It is also within the contemplation of the invention that the service provider may provide one allocated receiver (portable, mobile or base station) to each communication resource, e.g. frequency, for logging all of 1 7 the voice communications on that particular frequency. This could include recording all voice transmissions and/or recording the time periods that particular users utilise that frequency, by way of using their call ID.

The method for operating a voice logging function in the mobile/portable radio unit will now be described with reference to FIG. 4. In the preferred embodiment, the communication system is a Time Division Multiple Access (TDMA) communication system, having a number of frequency channels, wherein each radio frequency is divided into four time-slots. The method of operating a radio unit in a two way radio communication system includes setting up a call with another radio unit, as in step 100. If voice messages are to be recorded, as shown in step 102, the radio unit transmits on the at least one comirniini cation resource and stores samples of the transmitted and/or received speech in a memory element, as in step 104. If the call time factors are to be monitored and stored, as in step 106, the timer 41 in the processor 42 is started, and the time used transmitting, and perhaps receiving, on the at least one communication resource by the radio unit is monitored and stored, as shown in step 108. The stored call time factor data may include at least one of. details of the other party's callin ID, day, date, call start time, call duration, call end time, total call time. Once the call is terminated in step 110, the radio preferably checks to see whether it is connected to, or within range of a fixed voice logging or billing radio. If it is connected to such a radio, or within range, the radio unit may transmit the stored information to a fixed central unit for either storing the recorded voice centrally and/or determining the call charge rate to be billed to the radio unit, as shown in step 112.

As shown in FIG. 4, the operation of the voice recording function or call time factor monitoring function can be selectively enabled. Such a feature is beneficial in order to further control the amount of information to be stored in the radio unit. Furthermore, it is within the contemplation of the invention that such enabling of these functions can be initiated either by wireline or via over-the-air transmissions. This enables for example, a fixed unit of a police radio system to remotely initiate a voice monitoring or 8 voice recording functions in a remote radio immediately to record communications in an emergency situation.

In this manner, a two way communication system, a method of operating the two way communication system and a radio unit for use in the two-way commilnication system are provided which mitigate at least some of the aforementioned disadvantages with present communications systems.

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Claims

1. A two way radio communication system having a plurality of radio units communicating via at least one communication resource wherein at least one first radio unit of the plurality of radio units comprises:

a voice logger for recording voice communications of the at least one communication resource by the at least one first radio unit on the two way radio communication system.

2. A two way radio communication system according to claim 1, wherein the at least one first radio unit includes a receiver for receiving voice transmissions on the two way radio communications system and the voice logger includes a voice decoding element operably coupled to the receiver and a memory element for storing said voice transmissions after they have been received and decoded.

3. A two way radio communication system according to claim 1 or 2, wherein the voice logger records voice transmissions between the at least one first radio unit and any other radio unit of the plurality of radio units.

4. A two way radio communication system according to any one of preceding claims 1 to 3, wherein the at least one first radio unit further comprises a transmitter to transmit the stored voice transmissions to a central unit over the air or via a fixed communication link.

5. A two way radio communication system according to any one of the preceding claims wherein the voice logger can be selectively enabled according to voice of the two way radio communication system.

6. A two way radio communication system as claimed in any one of the preceding claims wherein the at least one communication resource is a frequency channel and the communication system is a Time Division Multiplex Access (TDMA) communication system operating in a direct mode of operation (DMO). 35 C.

7. A radio unit for use in a two way radio commilnication system according to any one of the preceding claims.

8. A radio unit for use in a two way radio communication system, the radio unit comprising a voice logger for recording voice information of at least one communication resource on the two way radio communication system by the first radio unit.

9. A radio unit according to claim 8 wherein the radio unit includes a receiver for receiving voice transmissions on the two way radio communications system and the voice logger includes a voice decoding element operably coupled to the receiver and a memory element for storing said voice transmissions after they have been received and decoded.

10. A radio unit according to claim 8 or 9, wherein the voice logger records voice transmissions between the first radio unit and any other radio unit of the plurality of radio units.

11. A radio unit according to any one of preceding claims 8 to 10, wherein the first radio unit further comprises a transmitter to transmit the stored voice transmissions to a central unit over the air or via a fixed communication link.

12. A radio unit according to any one of the preceding claims 8 to 11, wherein the voice logger can be selectively enabled according to the present voice of the two way radio communication system.

13. A method of operating a radio unit in a two way radio communication system having a plurality of radio units communicating via at least one communication resource the radio unit including a processor, the method comprising the steps of. transmitting on the at least one communication resource by the radio unit; and -W 11 recording voice transmissions to or from the radio unit on by the processor of the at leash one communication resource used by the radio unit.

14. A method of operating a radio unit in a two way radio communication system according to claim 13, wherein the radio unit includes a receiver for receiving voice transmissions on the two way radio communication system and includes a voice decoding element operably coupled to the receiver and a memory element, the method further comprising the step ofstoring voice transmissions in the memory element of the radio unit after they have been received and decoded.

15. A method of operating a radio unit in a two way radio communication system according to claim 13 or 14, wherein the radio unit ffirther comprises a transmitter, the method further comprising the step of. transmitting the stored voice transmissions to a central unit over the air or via a fixed communication link.

16. A method of operating a radio unit in a two way radio communication system according to any one of preceding claims 13 to 15, the method further comprising the steps of.. selectively enabling the voice monitoring or voice recording functions 25 according to the present voice of the two way radio communication system.

17. A communication system substantially as hereinbefore described with reference to, or as illustrated by, FIG. 1 or FIG. 2 of the drawings.

18. A at least one first radio unit substantially as hereinbefore described with reference to, or as illustrated by, FIG. 3 of the drawings.

19. A method of operating a communi on system substantially as hereinbefore described with reference to, or as illustrated by, FIG. 4 of the 35 drawings.