GB2370455A

GB2370455A - Automatically testing a radio unit/radio link where a serving unit receives from records and retransmits back to a wireless unit a voice test message

Info

Publication number: GB2370455A
Application number: GB0031090A
Authority: GB
Inventors: Kenneth Jahn Lavrsen
Original assignee: Motorola Inc
Current assignee: Motorola Solutions Inc
Priority date: 2000-12-20
Filing date: 2000-12-20
Publication date: 2002-06-26
Anticipated expiration: 2020-12-20
Also published as: GB2370455B; GB0031090D0

Abstract

A wireless communication system (10) includes a wireless serving communication unit (22-32), having a receiver and transmitter operably coupled to a voice recorder (136). The wireless communication system (10) includes at least one wireless communication unit (12-16) transmitting at least a portion of a voice test message 306 to the wireless serving communication unit (22-32). The wireless serving communication unit (22-32) receives the at least a portion of a voice test message 306, records the voice test message 306 in said voice recorder (136) and re-transmits the voice test message (312) back to said at least one wireless communication unit (12-16). The user will gain a good indication of the quality of the communication link as well as the operability of some radio functions, without disturbing say, a dispatcher of the communication system or any other radio users. Radio users are able to perform radio tests more often, to ensure that they are in range of the communication system. The radio user is also in a position to try out locations for optimal radio coverage before placing a call.

Description

WIRELESS COMMUNICATION SYSTEM, COMMUNICATION UNIT AND METHOD FOR AUTOMATICALLY TESTING A RADIO UNIT/RADIO LINK Field of the Invention This invention relates to wireless communication systems and, in particular, the testing of wireless communication units in such systems. The invention is applicable to, but not limited to, remote, automatic testing of radio units on an ad hoc basis.

Background of the Invention Wireless communications systems, for example cellular telephony or private mobile radio (PMR) communications systems, typically provide for radio telecommunication links to be arranged between a plurality of base transceiver stations (BTSs) and a plurality of subscriber units, often termed mobile stations (MSs).

In the art, the term mobile station generally includes both hand-portable and vehicular mounted radio units.

Furthermore, the communications link from a BTS to a MS is referred to as the down-link path. Conversely, the communications link from a MS to a BTS is referred to as the up-link path.

A popular version of the PMR communication system is twoway radio, where MSs communicate directly to each other, without the need for the communication to be passed through a BTS. An enhancement often provided to the basic two-way radio communication is in the use of a repeater station to extend the range of the communication link.

The repeater station generally performs minimal processing of received signals, typically sufficient processing to correct for any errors introduced in the up-link path, before re-transmitting (repeating) the received transmission to the intended recipient in the down-link path. Such processing may involve the decoding and re-encoding of received speech signals.

Wireless communication systems are distinguished over fixed communication systems, such as a public switched telephone network (PSTN), principally in that MSs are mobile (in the general sense) and therefore may move between service providers (and/or different BTS). In doing so, the MSs encounter varying radio propagation environments. As such, the functionality and system operation considerations in a wireless communication system are very different to wire-line communication systems.

In a wireless communication system, each BTS has associated with it a particular geographical coverage area (or cell). The coverage area defines a particular range that the BTS can maintain acceptable communications

with MSs in its cell. Often these cells combine to produce an extensive coverage area.

Multiple access techniques permit simultaneous transmissions from several MS to a single BTS over a plurality of communication channels. Some channels are used for carrying traffic whilst other channels (which may be logical or dedicated channels) are used for transferring control information, such as call paging, between the base station and subscriber units. Examples of multiple access techniques include: frequency division multiple access (FDMA), time division multiplexing/ multiple access (TDM, TDMA) and code division multiple access (CDMA).

The present invention finds particular application in the PMR domain of wireless communications.

In the field of the present invention, it is known that radio technicians will use a dedicated channel for testing link audio quality when servicing the PMR radio equipment. This dedicated channel is typically one of the normal traffic channels, taken out of service for this particular purpose. Additionally, in order to test the coverage to the infrastructure, the system must have a repeater function, thereby doubling the servicing voice communication links on the system.

In a related field of the present invention, it has been found that the use of coil cords for microphones is a common source of audio quality problems in radio

equipment. This problem is difficult to detect. The inventor of the present invention is unaware of any user friendly mechanism for checking the audio quality of a radio unit.

There are distinctive user requirements served by PMR, which are different from those supported by wireless telephony. One such requirement is the requirement to operate in emergency situations. This sort of requirement needs the simplicity and immediacy of'Push To Talk' (PTT) group call communications, as provided by PMR.

In the field of this invention it is common practice that users who are dependent on their two way radio perform regular radio checks (radio tests) as part of preparations for their daily routines. One typical example is in such public safety PMR systems where, say, a police officer will turn his portable radio on and call the radio dispatcher requesting a radio test. The dispatcher will listen to the message and confirm back to the radio unit user that the call was received and that the audio quality of the received signal was acceptable.

However, a disadvantage with the current radio test procedure is that the radio dispatcher needs to be present and available to receive the voice message. The dispatcher also has to spend time transmitting a message to the respective user to inform them that the voice message was received at an acceptable audio quality.

During this period the dispatcher is not able to communicate on an alternative channel. Furthermore, unless the communication link is made as a private call, this type of radio voice test will disturb other users on the same system or talk group.

Hence, particularly for a large communication system as typically found in public safety systems where there are hundreds of active radio units at any one time, the dispatcher may be continuously interrupted by such radio test requests. Clearly, the dispatcher function is a hindrance in the efficient and effective communication operation for such public safety systems. As such, each radio test is typically limited to a short period, with a simple confirmation that the radio channel is indeed open and working.

Furthermore, the users are encouraged to limit such radio test procedures to a minimum, and there is certainly no time for experimentation to determine particular problems with the radio or radio propagation link to the user's location. This may mean that the user has not properly checked the functioning of his/her radio unit, or the communication link to the radio system, before finding themselves in an emergency situation.

In the field of this invention, it is also known that a dispatcher can check whether a radio is powered on and within range of a wireless serving communication unit.

This dispatcher-controlled radio check is performed by the dispatcher entering the radio identification code

(ID) on a dispatch console and transmitting a special type of selective call, or call alert paging, to the radio. The mobile/portable then responds back to the dispatcher with an acknowledge message. This communication is silent and hidden to the mobile/portable user.

This function only gives a radio check possibility to the dispatcher and does not give any indication of the audio path and function. However, a portable user has two possibilities: requesting a check from the dispatcher or making a call to another radio within audio range, for example, a portable to mobile call.

The use of a dispatcher to test the working of many radios in the field is clearly an inefficient process and a waste of the dispatcher's valuable time.

Thus there exists a need in the field of the present invention to provide a wireless communication system, communication unit and method for automatically testing a radio unit and/or radio link wherein the abovementioned disadvantages may be alleviated.

Statement of Invention In accordance with the present invention there is provided a wireless Communication System, as claimed in claim 1.

In accordance with the present invention there is provided a communication unit, as claimed in claim 11.

In accordance with the present invention there is provided method for automatically testing a wireless communication unit or a wireless communication link, as claimed in claim 14.

Brief Description of the Drawings Exemplary embodiments of the present invention will now be described, with reference to the accompanying drawings, in which: FIG. 1 shows a block diagram of a radio communications system that can be adapted to support the various inventive concepts of a preferred embodiment of the present invention; FIG. 2 shows a block diagram of a wireless serving communication unit adapted to support the inventive concepts of the preferred embodiments of the present invention; and FIG. 3 shows a flow chart of a user-controlled automatic radio unit/radio link verification mechanism, in accordance with a preferred embodiment of the present invention.

Description of Preferred Embodiments In summary, the preferred embodiment of the invention allows a radio user to check that his/her radio is working and within coverage by using an automatic voice recording of a transmission which is re-transmitted back to the user. The embodiment consists of a special signalling scheme combined with a voice recording system.

FIG. 1 shows, in outline, a radio communications network 10, adapted in accordance with a preferred embodiment of the invention.

A plurality of subscriber units, such as a mixture of MSs 12-16 and fixed terminals (not shown), communicate 18-22 over any suitable air-interface. The MSs are shown with a variety of communication options. They can communicate 18-20 via at least one of a plurality of base transceiver stations (BTSs) 24-30 with other MSs. If the system offers telephone interconnect, the MSs can communicate 56-60 with fixed or cellular telephones via a conventional public switched telephone network (PSTN) 34.

Alternatively the MSs can communicate via a simple repeater station, such as MS 16 communicating 21,22 with MS 14 via repeater 32.

Each BTS 24-30 or repeater 32 is principally designed to serve its primary cell, with each BTS 24-30 or repeater 32 containing one or more transceivers. The BTSs 24-30 may be connected to the PSTN 34 through base station controllers (BSCs) 36-40.

Each BSC 36-40 may control one or more BTSs 24-32, with BSCs responsible for establishing and maintaining control channel and traffic channels to serviceable MSs affiliated therewith, as will be understood by those skilled in the art.

In the preferred embodiment of the invention, a voice recording function is provided in at least one of the wireless serving communications units. For simplicity purposes only, a first voice recording function 23 is shown in respect of BTS 25 and a second voice recording function 33 is shown in respect of Repeater 32. In an alternative embodiment of the present invention, the voice recording function 47 can be positioned at a higher layer in the communication system infrastructure, such as BSC 36.

If the inventive concepts described herein were applied to larger wireless communications systems, such voice recording functions could be provided for in an operations and management centre (OMC, not shown), linking the respective BSCs 36-40. In the preferred embodiment of the invention, the voice recording function is provided in the lower levels of the infrastructure such as BTS and/or repeater stations to avoid impacting signalling communications through the higher layers of the system.

In the preferred embodiment of the invention, at least one of the MS 12-16 transmits a voice message to a

wireless serving communication unit, such as BTS 25 or Repeater 32. The voice message is preferably sent in accordance with a special signalling scheme. As mentioned, the BTS 25 and Repeater 32 have been adapted to receive and record the voice message in voice recording functions 23,33, in accordance with the inventive concepts of the present invention.

The BTS 25 and Repeater 32 include a signalling processing function to determine that the received voice message is a test-voice message, in order to decide to record the test-voice message. Once the voice test message has finished, the BTS 25 or Repeater 32 retransmit the recorded voice test message to the MS 12-16 that initially transmitted the voice. In such a manner, the user of the respective MS 12-16 can automatically test the quality of the radio communication link with its serving communication unit, as well as the audio performance of the MS 12-16.

It is within the contemplation of the invention that alternative radio communication architectures could benefit from the inventive concepts described herein.

It is also within the contemplation of the invention that the indicated quality of the communication link includes any of the following: operational condition of a microphone function, a volume setting, radio coverage at the wireless communication unit, a radio propagation condition.

Turning now to FIG. 2, there is shown a block diagram of a wireless serving communication unit 100 adapted to support the inventive concepts of the preferred embodiments of the present invention. The wireless serving communication unit 100 contains an antenna 102 preferably coupled to a duplex filter or circulator 104 that provides isolation between receive and transmit chains within the wireless serving communication unit 100.

The receiver chain includes receiver front-end circuitry 106 (effectively providing reception, filtering and intermediate or base-band frequency conversion). The receiver front-end circuitry 106 is coupled to a signal processing function 108.

In the preferred embodiment of the invention, the receiver chain also includes received signal strength indicator (RSSI) circuitry 112 (shown coupled to the receiver front-end 106, although the RSSI circuitry 112 could be located elsewhere within the receiver chain).

The RSSI circuitry is coupled to a controller 114. The controller 114 is also coupled to the receiver front-end circuitry 106 and the signal processing function 108 (generally realised by a DSP).

The controller 114 may therefore receive bit error rate (BER) or frame error rate (FER) data from recovered information. In the preferred embodiment of the invention the wireless serving communication unit 100

may, in addition to receiving, recording and retransmitting the voice test message, perform a qualitative BER or FER measurement on the received voice message. This qualitative measurement may be retransmitted together with the re-transmitted voice test message to the MS user, so that the user can better determine the overall quality of the MS audio, base-band and RF functions, in addition to a quality of the communication link.

A timer 118 is typically coupled to the controller 114 to control the timing of operations (transmission or reception of time-dependent signals) within the MS. The received voice test message, once received and processed to determine that it is indeed a voice test message, is passed to speech processing unit 130. Speech processing unit 130 includes speech decoding function 132, operably coupled to voice recording function 136 and speech encoder function 134. The controller 114 is operably coupled to speech processing unit 130 to control the recording operation of the voice test message.

The controller and signalling processing function monitor the received voice test message until they determine that it has finished. At this time, the controller ensures that the recorded voice test message is passed to speech encoder 134 for conversion into a signal suitable for modulation and transmission by transmitter/modulation circuitry 122 and power amplifier 124. The transmitter/modulation circuitry 122 and the power amplifier 124 are operationally responsive to the

controller, with an output from the power amplifier coupled to the duplex filter or circulator 104.

Of course, the various components within the wireless serving communication unit 100 can be realised in discrete or integrated component form, with an ultimate structure therefore being merely an arbitrary selection.

Furthermore, a skilled person would readily recognise that alternative architectures could be implemented that would still employ the various inventive concepts of the present invention.

Turning now to FIG. 3, a flow chart 300 of a usercontrolled automatic radio unit/radio link verification mechanism is shown, in accordance with a preferred embodiment of the present invention.

First, when the radio user wants to perform a radio test the radio user initiates a special radio test mode 302 on the radio unit. Preferably, this special test mode is enabled by a dedicated (or even dual function) data entry element, for example a button on a keypad of the radio unit, or alternatively by entering a special test-mode code on the keypad. The radio unit then makes a voice test transmission 306 of typically a few seconds, to its wireless serving communications unit.

In the flowchart, boundary 304 indicates the transition of the voice test message from/to the radio unit, and

boundary 308 indicates the transition of the voice test message to/from the wireless serving communication unit.

In the preferred embodiment of the invention, the voice test message is transmitted using a particular signalling format to ensure that the call is not heard by other users or the dispatcher.

At the wireless serving communication unit, the voice test message is processed to determine that it is a voice test message. In response to a positive determination, the voice test message is recorded 310.

When the voice test message is completed, for example recognised by the user releasing the push to talk button (PTT), the voice is re-transmitted 312 back to the user as a private call, so that the user will be the only person who can hear that particular message.

When the test is complete, the radio unit may then leave its automatic test mode and go back to normal operation.

In the preferred embodiment of the invention, the radio test mode can be terminated in a number of ways, for example, time-out initiated by controller 114 in conjunction with timer 118, after one transmission, when receiving a call, or by depression of a data entry element such as a button on instructed by a menu etc.

It will be understood that the wireless communication system, communication unit and method for automatically testing a radio unit and/or radio link described above provides the following advantages:

(i) The user is more confident in the operability of their radio equipment. The user can repeat the test as often as desired or needed, which is particularly beneficial in public safety systems, where the ability to have an immediate communication link is critical.

(ii) The user will receive a useful indication of the combined transmit and receive path, including microphone function, volume setting and radio coverage, without interrupting the dispatcher or any other users.

(iii) The signalling can be specifically designed for the purpose, or the signalling can be readily implemented on existing standard techniques, such as selective call, call alert and/or private line signalling.

(iv) By a user having the flexibility to automatically test the radio and radio link, thereby avoiding impacting the work of a dispatcher, the user now has the possibility of experimenting with accessories in the field when a problem is identified. One example could be that the user can bend a wire of a microphone or clean the microphone connectors or contacts and determine the optimal operating arrangement by repeatedly testing voice transmissions.

(v) The user has the ability to move location and continue to initiate the voice test mode of operation to

determine the location offering an optimal signal quality level before placing a call.

It is within the contemplation of the invention that a dedicated signalling protocol can be designed for the purpose of this test mode. In an alternative embodiment, the signalling protocol can be based on standard selective call, call alert, or private call signalling or tone-in-band methods. One example could be in an analog system radio test can be a simple use of an alternative private line (PL) continuous tone clear signalling standard (CTCSS). An alternative example could be to employ a tone-in-band technique to transmit the test voice message, so as not to affect normal traffic communication.

It is within the contemplation of the invention, that the up-link and down-link transmissions of the voice test message can use different signalling techniques, according to the set-up and resource availability of the respective wireless serving communication unit (BTS, repeater, BSC or other radio system infrastructure component) and wireless communication (radio) unit.

It is also within the contemplation of the invention that only a portion of the voice test message is needed to accomplish the objective of the present invention, as compared to transmitting and receiving the complete voice test message.

Further, it is within the contemplation of the invention that the voice recorder may be at say, the BTS, whilst control of the transmissions could be controlled by a different element in the infrastructure.

Furthermore, in radio systems such as TErrestrial Trunked RAdio (TETRA) standard as defined by the European Telecommunication Standards Institute (ETSI), the voice test messaging can be implemented as a private calls and/or group calls. With such digital systems, the impact on memory space to record voice messages of typically less than say, 15 seconds, is minimal.

In summary, a wireless communication system (10) has been provided. The wireless communication system (10) includes a wireless serving communication unit (22-32), having a receiver and transmitter operably coupled to a voice recorder (136), and at least one wireless communication unit (12-16). The at least one wireless communication unit (12-16) transmits at least a portion of a voice test message (306) to the wireless serving communication unit (22-32). The wireless serving communication unit (22-32) receives the at least a portion of a voice test message (306), recording the at least a portion of a voice test message (306) in said voice recorder (136) and re-transmits the at least a portion of a voice test message (312) back to said at least one wireless communication unit (12-16).

A wireless serving communication unit (22-32) has also been provided that includes a voice recorder function (136) operably coupled to a controller (114), a receiver chain and a transmitter chain. The receiver (106) receives a voice test message from a wireless communication unit (12-16), records said voice test message in said voice recorder function (136) and retransmits at least a portion of said voice test message back to said wireless communication unit (12-16) once said receiving of said voice test message is completed.

In addition, a method for automatically testing a wireless communication unit (12-16) or a wireless communication link has been provided. The method includes the steps of: transmitting (306), by said wireless communication unit (12-16), at least a portion of a voice test transmission to a wireless serving communications unit (22-32); receiving said at least a portion of a voice test transmission at said wireless serving communication unit (22-32); recording (310) said at least a portion of a voice test message at said wireless serving communication unit (22-32) ; and retransmitting (312) automatically at least a portion of said voice test message from said wireless serving communication unit (22-32) to said wireless communication unit (12-16) once said receiving step has finished.

Thus a wireless communication system, communication unit and method for automatically testing a radio unit and/or radio link have been provided wherein the aforementioned problems with prior art arrangements are alleviated.

Claims

Claims 1. A wireless communication system, comprising a wireless serving communication unit, having a receiver and transmitter operably coupled to a voice recorder, and at least one wireless communication unit, said at least one wireless communication unit transmitting at least a portion of a voice test message to the wireless serving communication unit, the communication system characterised by the wireless serving communication unit receiving the at least a portion of a voice test message, recording the at least a portion of a voice test message in said voice recorder and re-transmitting the at least a portion of a voice test message back to said at least one wireless communication unit.
2. The wireless communication system according to claim 1, further characterised by said voice test message being transmitted and/or received on a signalling channel of the communication system.
3. The wireless communication system according to claim 1 or claim 2, wherein said wireless serving communication unit is a base transceiver station or repeater station or base site controller or radio system infrastructure component.
4. The wireless communication system according to any one of the preceding claims, where said at least a portion of a voice test message is a whole voice test message and is automatically re-transmitted once the whole of the voice test message has been received.
5. The wireless communication system according to any one of the preceding claims, wherein the voice test message is initiated by the user of the wireless communication unit according to at least one of the following: by depression of a dedicated or dual function button on said wireless communication unit, or by entering a special test-mode code on a data entry element of said wireless communication unit.
6. The wireless communication system according to any one of the preceding claims, wherein said wireless serving communication unit includes a signal quality measurement function operably coupled to said receiver, and said re-transmission of said at least a portion of a voice test message from said wireless serving communication unit to said wireless communication unit includes data indicating a quality of a communication link between said wireless serving communication unit and said wireless communication unit.
7. The wireless communication system according to any one of the preceding claims, the wireless serving communication unit further comprising determination means to determine that said transmission is at least a portion of a voice test message, and said recording of said at least a portion of a voice test message in said voice recorder is performed in response to a positive determination.
8. The wireless communication system according to any one of the preceding claims wherein the transmission or re-transmission of the at least a portion of a voice test message uses at least one of the following communication methods: a private call, a selective call, a call alert, tone-in-band.
9. The wireless communication system according to any one of the preceding claims wherein the test mode can be terminated in any one of the following ways: time-out of a timer, after receipt of a first re-transmission, interrupted on receiving a call, user initiated by depression of a data entry element.
10. The wireless communication system according to any one of the preceding claims wherein the use of a voice test message indicates a quality of a communication link, said indicated quality including at least one of the following: operational condition of a microphone function, a volume setting, radio coverage at said wireless communication unit, a radio propagation condition.
11. A wireless serving communication unit comprising a voice recorder function operably coupled to a controller, a receiver chain and a transmitter chain, said wireless serving communication unit characterised in that said receiver receives a voice test message from a wireless communication unit, records said voice test message in said voice recorder function and re-transmits at least a portion of said voice test message back to said wireless communication unit once said receiving of said voice test message is completed.
12. The wireless serving communication unit according to claim 11, wherein said wireless serving communication unit is a base transceiver station or repeater station or base site controller or radio system infrastructure component.
13. The wireless serving communication unit according to claim 11 or claim 12, wherein said wireless serving communication unit includes a signal quality measurement function operably coupled to said receiver, and said retransmission of at least a portion of said voice test message from said wireless serving communication unit to said wireless communication unit includes data indicating a quality of a communication link between said wireless serving communication unit and said wireless communication unit.
14. A method for automatically testing a wireless communication unit or a wireless communication link, the method comprising the steps of: transmitting, by said wireless communication unit, at least a portion of a voice test transmission to a wireless serving communications unit ; receiving said at least a portion of a voice test transmission at said wireless serving communication unit; recording said at least a portion of a voice test message at said wireless serving communication unit; and re-transmitting automatically at least a portion of said voice test message from said wireless serving communication unit to said wireless communication unit once said receiving step has finished.
15. The method for automatically testing a wireless communication unit or a wireless communication link according to claim 14, the method further characterised by the step of: determining, at the wireless serving communication unit that said received message is at least a portion of a voice test message and performing said recording step in response to a positive determination.
16. The method for automatically testing a wireless communication unit or a wireless communication link according to claim 14 or claim 15, wherein said voice test message is transmitted using a private signalling format.
17. The method for automatically testing a wireless communication unit or a wireless communication link according to any one of claims 14 to 16, the method further characterised by the step of: entering, by a user, a test mode of said wireless communication unit in order to initiate said transmission, receiving, recording and re-transmission steps.
18. The method for automatically testing a wireless communication unit or a wireless communication link according to any one of claims 14 to 17, further comprising the step of: terminating a voice test message mode in any one of the following ways: time-out of a timer, after receipt of a first re-transmission, interrupted on receiving a call, user initiated by depression of a data entry element.
19. A wireless communication system, substantially as hereinbefore described with reference to, and/or as illustrated by, FIG. 1 of the accompanying drawings.
20. A wireless serving communication unit, substantially as hereinbefore described with reference to, and/or as illustrated by, FIG. 2 of the accompanying drawings.
21. A method for automatically testing a radio unit and radio link, substantially as hereinbefore described with reference to, and/or as illustrated by, FIG. 3 of the accompanying drawings.