WO2013150346A1

WO2013150346A1 - Communications aid for end user cellular device

Info

Publication number: WO2013150346A1
Application number: PCT/IB2012/055826
Authority: WO
Inventors: Andries Petrus Cronje Fourie
Original assignee: Poynting Antennas (Pty) Limited
Priority date: 2011-10-25
Filing date: 2012-10-23
Publication date: 2013-10-10

Abstract

A communications aid 10 for a cellular end-user communications device 12 comprises a cellular device interface 16 for interfacing with the cellular end-user communications device. An antenna port 22 which is connectable to an auxiliary antenna 24. A switch arrangement 32 is provided for selectively making in time multiplex manner one of a) a receive path 26 from the antenna port 22 to the cellular device interface 16 and which receive path comprises a receive amplifier 30 and b) a transmit path 20 from the cellular device interface to the antenna port and which transmit path comprises a transmit amplifier 28.

Description

COMMUNICATIONS AID FOR END USER CELLULAR DEVICE INTRODUCTION AND BACKGROUND

This invention relates to wireless communications systems and more particularly to wireless cellular communications systems and a communications aid to be used with a cellular end-user communications device, such as a cellular or mobile phone, a cellular modem etc.

It often happens that a cellular end-user device for data and voice finds itself in a weak signal area and does not have adequate internal antennas to achieve satisfactory communication with a remote cellular base station. The situation may be improved by connecting an external antenna to the cellular end-user device. Connection to an external antenna may be performed be using an antenna connector on the device. However, in many cases, no connector is provided and/or the connector type is not easily sou reed. Recently, there have been developed aids comprising passive electromagnetic couplers to alleviate this situation. In use, these electromagnetic couplers are located close to the cellular device and couples to the fields generated by the small internal antenna of the cellular device. This coupled energy can then be provided to an external antenna, to improve the communication capability of the cellular end-user device. However, it is well known that the coupling achieved is not ideal and hence some of the power transmitted or received is lost in the coupling between the passive coupler and the cellular end-user device. Typical losses are in the range of 2 to 6 dB for a well designed coupler, which is ideally positioned relative to the cellular end-user device. These losses may be exacerbated by poor relative placement and/or orientation of the cellular end-user device and the coupler. Additionally, some transmit power is lost in a cable leading from the coupler to the external antenna. The problem may be alleviated by adding a bi-directional amplifier to the device, but current cellular bi-directional amplifiers are expensive, since they typically incorporate filters to separate the transmit signal from the receive signal.

OBJECT OF INVENTION

Accordingly it is an object of the present invention to provide an alternative communications aid with which the applicant believes the aforementioned disadvantages may at least be alleviated or which may provide a useful alternative for the known devices. SUMMARY OF INVENTION

According to the invention there is provided a communications aid for a cellular end-user communications device, the communications aid comprising: - a cellular device interface for interfacing with the cellular end- user communications device;

- an antenna port which is connectable to an auxiliary antenna; and

- a switch arrangement for selectively making in time multiplex manner one of a) a receive path from the antenna port to the cellular device interface and which receive path comprises a receive amplifier and b) a transmit path from the cellular device interface to the antenna port and which transmit path comprises a transmit amplifier.

The cellular device interface may comprise a coupler part or connector part. The coupler part may be an electromagnetic coupler part which may be used to establish an electromagnetic coupling between a complementary coupler part, such as an antenna, of the cellular end-user device and the electromagnetic coupler part. The electromagnetic coupling is preferably a near-field coupling, in that a separation D between the antenna and the electromagnetic coupler part is such that:

D< 2d/A

wherein λ is the wavelength of a carrier of the signal to be transmitted or received and d is the larger of the maximum dimension of either the electromagnetic coupler part or the complementary coupler part.. The carrier may have any suitable and scalable frequency, but preferably is in a first band of 800Mhz to 1000MHz or a second band of 1700MHz to 2200MHz.

The aid may comprise a housing carrying the electromagnetic coupler part, the receive and transmit paths, the switch arrangement and the antenna port. The housing may be in the form of a cradle for receiving the cellular end-user communications device and may be mountable on a host, such as a vehicle, or may be portable.

The auxiliary antenna may be separate and connectable to the antenna port via a cable. In other embodiments, the auxiliary antenna may permanently be connected to the antenna port and provided on the housing.

The switch arrangement may be configured normally and as a default to make the receive path, and to make the transmit path upon detection of a transmit signal originating from the cellular end-user communications device.

The communications aid may comprise an automatic controller for the switch arrangement, the controller comprising a transmit signal detector and being configured upon detection of a signal having a signal strength above a threshold value, to cause the switch arrangement to make the transmit path.

In some embodiments, the switch arrangement may be configured selectively to switch on, in time multiplex manner, one of the receive amplifier and transmit amplifier, thereby to make the receive path or transmit path, as the case may be.

The transmit amplifier may be connected in a transmit segment between the cellular device interface and the antenna port and the receive amplifier may be connected in a receive segment between the antenna port and the cellular device interface and which receive branch is parallel to the transmit branch.

In other embodiments, the switch arrangement may comprise a first switch and a second switch, the first switch may comprise a first pole connected to the transmit segment, a second pole connected to the receive segment and a selector connected to the cellular device interface and the second switch may comprise a first pole connected to the transmit segment, a second pole connected to the receive segment and a selector connected to the antenna port.

In yet another embodiment of the communications aid the cellular device interface may comprise a transmit signal frequency modulator arrangement comprising a plurality of input ports which are connectable to a plurality of device ports and an output port; and a receive signal frequency demodulator arrangement comprising an input port and a plurality of output ports which are connectable to the plurality of device ports respectively, the communications aid may further comprise an antenna interface comprising a transmit signal frequency demodulator arrangement having an input port and a plurality of output ports which are connectable via the antenna port to a plurality of antennas; and a receive signal frequency modulator arrangement comprising a plurality of input ports which are connectable to the plurality of antennas and an output port; and the switch arrangement may be operative to make the receive path by connecting via a cable the output port of the receive signal frequency modulator arrangement to the input port of the receive signal frequency demodulator arrangement and to make the transmit path by connecting via the said cable the output port of the transmit signal frequency modulator arrangement to the input port of the transmit signal frequency demodulator arrangement.

In this embodiment, the switch arrangement may comprise a first switch and a second switch, the first switch may comprise a first pole connected to the output port of the transmit signal frequency modulator arrangement, a second pole connected to the input port of the receive signal frequency demodulator arrangement and a selector connected to one end of the cable and the second switch may comprise a first pole connected to the input port of the transmit signal frequency demodulator arrangement, a second pole connected to the output port of the receive signal frequency modulator arrangement and a selector which is connected to the other end of the cable.

The transmit amplifier may be provided between the output port of the transmit signal frequency modulator arrangement and the first switch.

The receive amplifier may be provided between the output port of the receive signal frequency modulator arrangement and the second switch.

The cellular device interface may comprise any suitable kind of connection arrangement for connecting to the device ports, including, but not limited to an arrangement of electromagnetic coupler parts.

BRIEF DESCRIPTION OF THE ACCOMPANYING DIAGRAMS

The invention will now further be described, by way of example only, with reference to the accompanying diagrams wherein:

figure 1 is a basic block diagram of an example embodiment of a communications aid in cooperating relationship with a cellular end-user communications device, which, in the embodiment shown, is a cellular or mobile phone; figure 2 is a diagram similar to figure 1 illustrating the communications aid cooperating with a different type of cellular end-user device, which, in the embodiment shown, is a cellular USB modem;

figure 3 basic block diagram of another embodiment of the communications aid cooperating with a multi-input multi- output (MIMO) cellular end-user device; and

figure 4 is a more detailed diagram of part of the communications aid shown in figure 3.

DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

One example embodiment of a communications aid for a cellular end-user device 12 is generally designated by the reference numeral 10 in figures 1 and 2.

The aid 10 comprises a portable housing 14. Located in or on the housing there is provided a cellular device interface comprising an electromagnetic coupler part 16. The coupler part 16 is configured to be brought into electromagnetic coupling relationship with a complementary coupler part on the cellular end-user device 12, for example an antenna 18 of the device. An antenna port 22 on the housing is connectable to an auxiliary antenna 24. A switch arrangement 32 selectively makes or closes in time multiplex manner one of a receive path from the antenna port 22 to the cellular device interface 16 and a transmit path from the cellular device interface 16 to the antenna port 22. The receive path comprises a segment 26 that is parallel to a segment 20 of the transmit path. A receive amplifier 30 is connected in the receive segment and a transmit amplifier 28 is connected in the transmit segment.

The switch arrangement 32 comprises a first switch 32.1 and a second switch 32.2. The first switch 32.1 comprises a first pole 32.1 1 which is connected to the transmit segment 20, a second pole 32.12 which is connected to the receive segment 26 and a selector 32.13 which is connected to the electromagnetic coupler part 16. The second switch 32.2 comprises a first pole 32.21 which is connected to the transmit segment 20, a second pole 32.22 which is connected to the receive segment 26 and a selector 32.23 which is connected to the antenna port 22.

Normally and as a default, the receive path is made or closed and the transmit path is open.

The communications aid 10 further comprises an automatic controller 34 for the switch arrangement 32. The controller 34 comprises an arrangement 36 which is sensitive to a signal originating from the cellular end-user device and a signal detector 38 connected to said sensitive arrangement 36. The signal detector 38 is configured upon detection of a signal having a signal strength larger than a threshold value, to make or close the transmit path and to open or break the receive path. When the signal level drops below the threshold level again, the transmit path is opened or broken and the receive path is made or closed.

The communications aid 10 may further comprise a local power supply 40 for supplying power to electronic components of the communications aid requiring power for their operation, such as components 28, 30 and 38. In some embodiments the local power supply may comprise a rechargeable battery (not shown) in known manner.

In other embodiments, the communications aid may comprise an umbilical power cable (not shown in figure 1 ), which, at a free end thereof, is connected to a suitable connector, such as a USB or jack plug. The cable, towards the other end thereof, extends into the housing 14 and is connected in known manner to the electronic components of the communications aid requiring power for their operation. The aforementioned connector is removably connectable to a power outlet socket of the cellular end-user device 12, so that the communications aid derives power from the same power source as the cellular end-user device

12. For example, in figure 2, there is shown an arrangement wherein the communications aid 10 cooperates with wireless modem 50 connected in known manner to a laptop computer 52 via a first USB port 54 of the computer. The connector 44 of the power cable 42 of the communications aid 10 is connected to a second USB port 56 of the computer 52. The coupler part 16 of the aid 10 and an antenna (not shown) of the modem 50 are positioned in electromagnetic coupling relationship with one another.

In the example embodiments of figures 1 and 2, only one cellular device 12 is catered for. In these embodiments, the switch arrangement 32 is configured normally and as a default, to connect the receive path between the antenna port 22 and the electromagnetic coupler 16. Signals received from a cellular base station and via auxiliary antenna 24 are then amplified by receive amplifier 30 and fed to the coupler part 16, to be coupled electromagnetically to the conventional antenna 18 of the cellular device.

It is known that an outbound signal originating from the cellular end-user device 12 has a much larger signal strength than any received signal received via the auxiliary antenna. Only when an outbound signal originating from the cellular end-user device is detected - and which may be detected by by the controller 34 in that its signal strength exceeds a threshold value - is the switch arrangement 32 activated to break the receive path 26 and to make the transmit path 20 between the coupler part 16 and the antenna port 22, so that the outbound signal is amplified by transmit amplifier 28, before the outbound signal is fed via antenna port 22 to be transmitted by auxiliary antenna 24.

In the example embodiment 100 of the communications aid illustrated in figures 3 and 4, the cellular end-user device may be a multi-input multi- output (MIMO) device 1 12 comprising four device ports 1 12.1 to 1 12.4. In conventional devices if this kind, four separate cables are required to connect the ports 1 12.1 to 1 12.4 of the device 1 12 to respective auxiliary antennas 124.1 to 124.4.

The communications aid 100 comprises a cellular device interface 101 , which is connectable to the four ports of the device 1 12. The aid further comprises an antenna interface 103, which is connectable via an antenna port 122 to four auxiliary antennas 124.1 to 124.4. The device interface 101 comprises a transmit signal frequency modulator arrangement 102 and a receive signal frequency demodulator arrangement 104. The transmit signal frequency modulator arrangement comprises four input ports 102.1 to 102.4 which are connectable to the device ports 1 12.1 to 1 12.4 and a single output port 106. The receive signal frequency demodulator arrangement 104 comprises a plurality of output ports 104.1 to 104.4 which are connectable to the device ports and a single input 108. The output port 106 of the transmit signal frequency modulator arrangement 102 is connected to a first pole 132.1 1 of a first switch 132.1 of a switch arrangement 132 and a second pole 132.12 of the first switch 132.1 is connected to the input port 108 of the receive signal demodulator arrangement 104.

The antenna interface 103 comprises a transmit signal frequency demodulator arrangement 110 and a receive signal frequency modulator arrangement 1 16. The transmit signal frequency demodulator arrangement comprises four output ports 1 10.1 to 1 10.4 which are connectable to the antennas 124.1 to 124.4 and a single input port 1 14. The receive signal frequency modulator arrangement 116 comprises a plurality of input ports

116.1 to 1 16.4 which are connectable to the antennas and a single output port 1 18. The input port 1 14 of the transmit signal frequency demodulator arrangement 1 10 is connected to a first pole 132.21 of a second switch

132.2 of the switch arrangement 132 and a second pole 132.22 of the second switch 132.2 is connected to the output port 1 18 of the receive signal frequency demodulator arrangement 1 16.

The auxiliary antennas 124.1 to 124.4 are connected via the antenna port 122 to the respective output ports 1 10.1 to 1 10.4 of the transmit signal frequency demodulator arrangement 110 and the input ports of the receive signal frequency modulator arrangement 116. The selectors 132. 3 and 132.23 of the first and second switches are connected to a suitable conductor, such as a coaxial cable 140. The switch arrangement 132 may be configured, as hereinbefore described, so that the selectors 132.13 and 132.23 are normally, or as a default, connected to make a receive path 126 between the antenna interface 103 and the device interface 101. Only when an outbound signal propagating from any one of the device ports 1 12.1 to 112.4 is detected by the controller 134, as hereinbefore described, is the switch arrangement 132 activated to break or open the receive path 126 and to make or close the transmit path 120 between the device interface 101 and the antenna interface 103.

A transmit signal amplifier 150 with suitable broad band characteristics may be provided between the output 106 of the transmit signal frequency modulator arrangement 102 and the switch 132.1. A receive signal amplifier 1 52 with suitable broad band characteristics may be provided between the output 1 18 of the receive signal frequency modulator arrangement 16 and the switch 132.2.

In figure 4, transmission of signals via the aid 100 is illustrated in more detail. Reception, which would be the inverse and clear to a person skilled in the art, is hence not described in detail hereinafter. In transmit modulator arrangement 102, the baseband signals at f_c received from the ports 1 12.1 to 1 12.4 of the MIMO device 1 12 are mixed upwardly in the frequency domain, in known manner, with a respective mixing signal fi to f₄, to separate them in the frequency domain, as illustrated at 160, before being fed via the switch 132.1 into the coaxial cable 140. In the transmit path 120, these signals may be amplified by the broad band transmit amplifier 1 50, before being received at the input 1 14 of the transmit signal demodulator arrangement 1 10. In the transmit signal demodulator arrangement 1 10, the aforementioned modulated signals are demodulated back to base band f_c by down-mixing them with the mixing signals fi to f₄ respectively. The demodulated signals are transmitted via the auxiliary antennas 24.1 to 24.4, respectively.

DC electrical power for operation of the communications aid 100 may be provided or derived from the cellular end-user device in a manner similar to that hereinbefore described with reference to communications aid 10. Furthermore, DC power for components such as the transmit signal frequency demodulator arrangement 1 10 and receive signal frequency modulator arrangement 1 16 may be provided via the coaxial cable 140.

It will be appreciated that apart from the switch arrangements as herein described any one of the transmit and receive paths may be made or closed by switching on DC power to the relevant signal amplifier in the path and may be broken or opened by switching off or interrupting the DC power to the relevant amplifier. Other suitable time multiplexing switching techniques will be clear to the person skilled in the art and are covered by the appended claims.

Claims

1. A communications aid for a cellular end-user communications device, the communications aid comprising:

- a cellular device interface for interfacing with the cellular end- user communications device;

- an antenna port which is connectable to an auxiliary antenna: and

- a switch arrangement for selectively making in time multiplex manner one of ) a receive path from the antenna port to the cellular device interface and which receive path comprises a receive amplifier and b) a transmit path from the cellular device interface to the antenna port and which transmit path comprises a transmit amplifier.

A communications aid as claimed in claim 1 wherein the cellular device interface comprises an electromagnetic coupler part which, in use, serves to establish an electromagnetic coupling with a complementary coupler part of the cellular end-user communications device.

A communications aid as claimed in claim 2 wherein the electromagnetic coupling is a near-field coupling. A communications aid as claimed in any one of claims 1 to 3 wherein the switch arrangement is configured normally and as a default to make the receive path, and to make the transmit path upon detection of a transmit signal originating from the cellular end- user communications device.

A communications aid as claimed in claim 4 comprising an automatic controller for the switch arrangement, the controller comprising a transmit signal detector and being configured upon detection of a signal having a signal strength above a threshold value, to cause the switch arrangement to make the transmit path.

6. A communications aid as claimed in any one of claims 1 to 5 wherein the switch arrangement is configured selectively to switch on, in time multiplex manner, one of the receive amplifier and transmit amplifier, thereby to make the receive path or transmit path. 7. A communications aid as claimed in any one of claims 1 to 6 wherein the transmit amplifier is connected in a transmit segment between the cellular device interface and the antenna port and the receive amplifier is connected in a receive segment between the antenna port and the cellular device interface and which receive segment is parallel to the transmit segment.

A communications aid as claimed in any one of claims 6 and 7 wherein the switch arrangement comprises a first switch and a second switch, wherein the first switch comprises a first pole connected to the transmit segment, a second pole connected to the receive segment and a selector connected to the cellular device interface and wherein the second switch comprises a first pole connected to the transmit segment, a second pole connected to the receive segment and a selector connected to the antenna port.

A communications aid as claimed in any one of claims 1 to 6 wherein the cellular device interface comprises a transmit signal frequency modulator arrangement comprising a plurality of input ports which are connectable to a plurality of device ports and an output port; and a receive signal frequency demodulator arrangement comprising an input port and a plurality of output ports which are connectable to the plurality of device ports respectively; wherein the communications aid further comprises an antenna interface comprising a transmit signal frequency demodulator arrangement having an input port and a plurality of output ports which are connectable via the antenna port to a plurality of antennas; and a receive signal frequency modulator arrangement comprising a plurality of input ports which are connectable to the plurality of antennas and an output port; the switch arrangement being operable to make the receive path by connecting via a cable the output port of the receive signal frequency modulator arrangement to the input port of the receive signal frequency demodulator arrangement and to make the transmit path by connecting via the said cable the output port of the transmit signal frequency modulator arrangement to the input port of the transmit signal frequency demodulator arrangement.

10. A communications aid as claimed in claim 1 1 wherein the switch arrangement comprises a first switch and a second switch, wherein the first switch comprises a first pole connected to the output port of the transmit signal frequency modulator arrangement, a second pole connected to the input port of the receive signal frequency demodulator arrangement and a selector connected to one end of the cable and wherein the second switch comprises a first pole connected to the input port of the transmit signal frequency demodulator arrangement, a second pole connected to the output port of the receive signal frequency modulator arrangement and a selector which is connected to the other end of the cable. A communications aid as claimed in claim 10 wherein the transmit amplifier is provided between the output port of the transmit signal frequency modulator arrangement and the first switch. 12. A communications aid as claimed in claim 10 or claim 1 1 wherein the receive amplifier is provided between the output port of the receive signal frequency modulator arrangement and the second switch.

13. A communications aid as claimed in any one of claims 2 to 10 comprising a housing carrying the electromagnetic coupler part, the receive and transmit paths, the switch arrangement and the antenna port.

14. A communications aid as claimed in any one of claims 1 to 1 1 which is powered by a power supply of the end-user communications device.