WO2012048735A1

WO2012048735A1 - Methods and arrangements in a communication system

Info

Publication number: WO2012048735A1
Application number: PCT/EP2010/065258
Authority: WO
Inventors: Andreas Nilsson; Anders Derneryd; Jonas FRIDÉN; Lars Manholm
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2010-10-12
Filing date: 2010-10-12
Publication date: 2012-04-19

Abstract

A user equipment (100) in a communication system, which user equipment including at least one antenna (1) configured for receiving and transmitting radio signals, and at least one high frequency interface (2) configured for receiving and transmitting high frequency signals. In addition, the user equipment (100) includes a converter (3) configured for converting radio signals to high frequency signals and converting high frequency signals to radio signals, and a processor (4) configured for processing signals for reception and transmission on the at least one antenna (1) and / or the high frequency interface (2).

Description

METHODS AND ARRANGEMENTS IN A COMMUNICATION

SYSTEM

TECHNICAL FIELD

The present invention relates to communication systems, in particular to methods and arrangements for antenna diversity and MIMO in such systems.

BACKGROUND

In present day communication systems, there is a constant demand for higher throughput and quality for mobile broadband, and the pressure on network operators to increase the network capacity has become more and more intense. One well known way of doing this is to employ more antennas, so called MIMO, both at the base stations and at the user equipment e.g. mobile phones. In present base stations for mobile communication, large antenna separations as well as orthogonally polarized antennas are utilized to provide low radiation pattern correlation and low losses due to reduced mutual coupling. However, in user equipment where the physical structure is small, antennas are by necessity placed in close vicinity to each other. This may cause increased signal correlation and reduced antenna efficiency, both of which tend to degrade performance for wireless systems employing MIMO access schemes.

Another way of increasing the capacity in a communication network is to introduce antenna diversity at the user equipment, i.e. essentially an extra antenna receiving the same signal as the other antennas and in a smart way analyzing the signals from the antennas in order to achieve a large signal to noise ratio (SNR). However, due to the already mentioned small physical size of cell phones, the introduction of an extra diversity antenna is in most cases excluded. There are a lot of prior art on using an extra external antenna for mobile devices to increase the channel capacity. The external antenna is either connected to the mobile device through a cable or a wireless interface. The signal received at the external antenna is demodulated, decoded and processed before it is retransmitted to the mobile device. This means that a radio frequency radio chain is implemented in the vicinity of or close to the external antenna.

In the future, the use of hands-free will probably increase. One reason for this is that it is prohibited in many countries to simultaneously drive a car and talk in a cell phone without using a hands-free. Then almost all people will have to use hands-free daily. The document US 2009/0170455 is related to receive diversity and multiple input multiple output, and more specifically to receive diversity and multiple input multiple output using multiple mobile devices. A mobile device includes an antenna, the antenna being capable of receiving a signal, an interface, the interface being capable of receiving a second signal in synchronization with the signal, and an application, the application configured to perform receive diversity and /or multiple input multiple output processing using the signal and the second signal. A mobile device receives a first signal directly and may receive one or more second signals (demodulated data) from other devices and synchronously processes the first and the one or more second signals. The data (soft bits) from the second signal may be transmitted from the second high bandwidth, low latency interface on the second mobile device to the first high bandwidth low latency interface on the first mobile device. The second signal may be transmitted via a wired or wireless transmission (UWB, WiMAX, USB, a microwave interface, etc.). Synchronization information may be communicated between the first mobile device and the second mobile device via the high bandwidth, low latency interface of these devices.

One problem with the user equipment of today is that only a few antennas will fit in the small physical size of the user equipment. These antennas will in addition be placed close to each other, which may cause high signal correlation and low antenna efficiency. High signal correlation and low antenna efficiency tend to reduce the channel capacity. Another problem is that when using a user equipment in browser mode, the hand of the user usually covers part of the antennas, which reduces the antenna efficiency.

A known concept for increasing transmission and receiving reduncancey and/ or increase the bandwidth of a communication unit in a communication network is called VMAT (Virtual Multiple Antennas) [1]. Basically, the concept of VMAT emulates a MIMO terminal which allows using transmission schemes involving several radio channels, without incorporating several antennas in the same device. A communication network comprises a mobile unit and a plurality of peripheral devices, all of which share a common ID towards a base station. As a result, the base station will perceive the network as a single mobile unit with a plurality of antennas.

The radio frequency radio chain and base band processing implemented close to an external antenna are costly, consume energy, and introduce latency, which deteriorate the channel capacity of the communication link between the base station and the mobile device. Furthermore, synchronization data needs to be communicated between the mobile device and the radio chain connected to the external antenna.

Therefore there is a need for a solution to the above mentioned problems in order to improve the diversity and MIMO capability of a user equipment without the drawbacks presented by the use of multiple integrated antennas or external antennas of prior art.

SUMMARY The present disclosure provides a user equipment and a hands-free device in a communication system and methods of receiving and transmitting signals in the user equipment and hands-free device. A first aspect of the present disclosure provides a user equipment in a communication system. The user equipment includes at least one antenna configured for receiving and transmitting radio signals, and at least one high frequency interface configured for receiving and transmitting high frequency signals. Further, the user equipment includes a converter configured for converting received radio signals to high frequency signals and converting received high frequency signals to radio signals. Finally, the user equipment includes a processor configured for processing signals for reception and transmission on the at least one antenna and/ or the high frequency interface.

A second aspect of the present disclosure provides a wireless hands-free device or satellite device for a user equipment in a communication system. The device includes an antenna configured for communication with a base station, and at least one high frequency interface configured for communication with at least the user equipment. In addition, the device includes a converter configured for converting a radio signal received on the antenna into a high frequency signal for transmission over the at least one high frequency interface, or for converting a high frequency signal received on the at least one high frequency interface into a radio signal for transmission on the antenna, wherein the high frequency signal comprises a representation of the radio signal. A third aspect of the present disclosure provides a method of receiving signals in a user equipment in a communication system. The method includes the steps of receiving at least one radio signal on at least a first antenna in the user equipment, and receiving a high frequency signal over at least one high frequency interface in the user equipment, which high frequency signal comprises a representation of the radio signal. Finally, the method includes converting the received high frequency signal into the radio signal, and selectively and processing the radio signal from the at least a first antenna, and the converted high frequency signal to decode said radio signal.

A fourth aspect of the present disclosure provides a method of transmitting signals in a user equipment in a communication system. The method includes providing at least one radio signal in the user equipment, and converting the provided radio signal into a high frequency signal representative of the radio signal, and finally selectively transmitting the high frequency signal over at least one high frequency interface to a wireless hands-free device and/ or transmitting the provided radio signal on at least one antenna to a base station.

A fifth aspect of the present disclosure provides a method of relaying signals in a wireless hands-free device or satellite device to a user equipment in a communication system. This is enabled by receiving a high frequency signal representative of a radio signal over at least one high frequency interface in the device, converting the received high frequency signal into the radio signal, and finally transmitting the radio signal from at least one antenna in the device, to a base station.

A sixth aspect of the present disclosure provides a method of relaying signals in a wireless hands-free device or satellite device to a user equipment in a communication system. This is enabled by receiving a radio signal on at least one antenna in the device, converting the radio signal into a high frequency signal representative of the radio signal, and finally transmitting the high frequency signal over at least one high frequency interface in the device, to a user equipment.

Advantages of the present disclosure include that since no extra radio chain or base band processing has to be implemented close to the external antenna, the cost is reduced, energy is saved, and the latency is decreased compared to methods that require demodulating and modulating of a signal. BRIEF DESCRIPTION OF THE DRAWINGS

The invention, together with further objects and advantages thereof, may best be understood by referring to the following description taken together with the accompanying drawings, in which:

Fig. 1 illustrates a communication system according to the present invention;

Fig. 2 illustrates a user utilizing an embodiment of a user equipment according to the present invention;

Fig. 3. illustrates an embodiment of a communication system according to the present invention;

Fig. 4 illustrates an embodiment of a user equipment according to the present invention;

Fig. 5 illustrates an embodiment of a wireless hands free device according to the present invention;

Fig. 6 illustrates an embodiment of a receiving method in a user equipment according to the present invention;

Fig. 7 illustrates an embodiment of a transmission method in a user equipment according to the present invention;

Fig. 8 illustrates an embodiment of relaying received radio frequency signals in a hands free device according to the present invention;

Fig. 9 illustrates an embodiment of relaying received high frequency signals in a hands free device according to the present invention;

Fig. 10 illustrates an embodiment of a receiving method in a communication system according to the present invention;

Fig. 1 1 illustrates a further embodiment of a receiving method in a user equipment according to the present invention;

Fig. 12 illustrates an embodiment of a transmitting method in a user equipment according to the present invention. ABBREVIATIONS

MIMO Multiple Input Multiple Output

MISO Multiple Input Single Input

RF Radio Frequency

SIMO Single Input Multiple Output

SINR Signal To Interference and Noise Ratio

TRX Transceiver

UE User Equipment

VMAT Virtual Multiple Antennas

DETAILED DESCRIPTION

Today an increasing number of mobile phone users utilize wireless hands- free devices when using their mobile phones or other mobile user equipment, and the use of wireless hands-free devices is a rapidly developing field of technology. A hands-free device is a device that can be attached to the ear and then used for talking, without a need to pull the mobile phone or other user equipment out of the users pocket or other container.

A basic concept of the present disclosure is to integrate an external antenna in a wireless hands-free device. This antenna can then be used by a user equipment as an extra diversity or MIMO antenna. The term user equipment is used to described a wide range of wireless devices, such as mobile phones, PDA's, laptops etc. To make it possible for the user equipment to use the antenna integrated in the wireless hands-free device, a wireless interface between the hands-free device and the user equipment is also implemented, so that the signal received from the base station by the antenna in the hands-free can be sent to the mobile device or vice versa. This wireless interface preferably has the property that the signal received in the hands- free does not have to be digitally demodulated, decoded, coded and then digitally modulated again before it can be retransmitted, because then there must be a complete radio transceiver in the hands-free device, which will be costly and consume energy. Latency will then also be introduced, which probably will deteriorate the channel capacity between the base station and the mobile device. Therefore, the wireless interface is proposed to be radio frequency over wireless high frequency e.g. optical. This way, the received signal received from the base station in the antenna at the hands-free device can be used to directly modulate the high frequency e.g. optical signal. In addition, the received high frequency signal in the hands-free device can be demodulated and retransmitted to the base station as a radio frequency signal. With reference to Figure 1 a base station BS, a mobile phone 100, and a wireless hands-free device 200 according to the present invention are illustrated. The mobile or cell phone 100 has established a direct wireless communication link (such as 2G, 2.5G, 3G or LTE) with the base station BS. The cell phone 100 can, according to the present disclosure, also establish a second wireless communication link with the base station BS via the wireless hands-free device 200, where the wireless hands-free device 200 is used more or less like a repeater or relay station, although the wireless hands-free device 200 (and of course the cell phone 100) in this case also includes a frequency conversion. The radio frequency over wireless optical interface e.g. high frequency interface between the wireless hands-free 100 and the phone 200 is chosen because then there is no need for a radio chain and base band processor at the hands-free 200, only an radio frequency to optical and an optical to radio frequency converter.

Note that the carrier frequency of the communication link between the wireless hands-free and the user equipment e.g. cell phone is not limited to be in the optical or high frequency range, but it can be any frequency that is essentially higher than the radio carrier frequency, so that the radio frequency signal can be converted directly to the higher frequency..

In order to transfer information via the radio frequency over wireless optical interface there must usually be a line of sight between the transmitter and the receiver e.g. between the hands-free device and the mobile phone. However, recent advances in the optical wireless field have shown that it can also work in some non-line of sight conditions [2]. Further, the line of sight condition is not really a problem, because the need for high data rates in the cell phone is predominantly only needed when the cell phone is used in a browse mode and the user obviously needs a clear view of a graphic screen on the mobile phone. This is illustrated in Figure 2 where a user is using the cell phone 100 in browse mode. Browser mode means that the cell phone is utilized by watching the screen, e.g. using Internet or watching a movie. Moreover, as can be seen in Figure 2, there is no problem to achieve line of sight between the cell phone 100 and the hands-free 200 when the cell phone is used in browser mode.

Figure 3 illustrates a further embodiment of the present disclosure. The cell phone 100 of this embodiment has two antennas 1 , 1 1 , 12. Normally the antennas 1 , 1 1, 12 are integrated in the cell phone 100, but for illustration purposes the two antennas 1 have been placed outside the cell phone 100. The hands-free device 200 has one antenna 10. The antenna 10 in the hands-free device 200 could also be integrated, but is here shown as external to make it more illustrative. The cell phone 100 has established a wireless communication link (such as 2G, 2.5G, 3G or LTE (Long Time Evolution)) with the base station BS directly and indirectly via the hands-free device 200. The wireless communication link between the base station BS and the cell phone 100, and the wireless communication link between the base station BS and the hands-free device 200 are preferably utilizing the same communication type e.g. radio frequency. The communication between the cell phone 100 and the hands-free device 200 is via a high frequency interface e.g. a radio frequency over wireless optical interface. The two antennas 1 , 1 1 , 12 on the cell phone 100 are very close to each other and will therefore experience high signal correlation and high mutual coupling, which will reduce the performance of the communication link between the base station BS and the cell phone 200. The hand of the user that holds the cell phone 100 will also potentially reduce the efficiency of the antennas 1 , 1 1, 12 (especially if they are integrated in the cell phone 100 and partly covered by the hands of the user), which will reduce the channel capacity for the communication link.

In contrast, the antenna 10 at the hands-free device 200 has a large spatial distance from the antennas 1 , 1 1 , 12 in the cell phone 100 and therefore the antenna 10 at the hands-free device 200 has low signal correlation and low mutual coupling to the antennas 1 , 1 1, 12 in the cell phone 100. There is also no hand that covers the antenna 10 at the hands-free device 200 and therefore the efficiency will be high. Therefore, the channel capacity between the base station BS and the cell phone 100 can be largely increased when the cell phone 100 can use the antenna 10 at the hands-free 200 as an additional antenna. One way that the cell phone 100 can use the antenna 10 at the hands-free device 200 is as a diversity or MIMO antenna. The cell phone 100 has only two radio chains and uses switches to choose a subset of two out of three possible antennas (two in the cell phone and one in the hands-free) . With reference to Figure 4, an embodiment of a user equipment 100 e.g. mobile phone 100 in a mobile communication system will be described below. The user equipment 100 includes at least one antenna 1 , 1 1, 12 configured for receiving and transmitting radio frequency signals to and from a base station. As can be seen in the Figure. 4, the at least one antenna 1, 1 1, 12 is connectable to radio chain e.g. transceiver TRX. In addition, the user equipment 100 includes at least one wireless high frequency interface 2 configured for receiving and transmitting high frequency signals from and to a wireless hands free device or other satellite equipment to the user equipment 100. The wireless high frequency interface 2 is connectable to a converter 3 configured for converting radio frequency signals to high frequency signals and converting high frequency signals to radio frequency signals. Further, the converter is connectable to a radio chain or transceiver TRX. Finally the user equipment 100 includes a processor 4 configured for jointly processing signals for reception and transmission on the at least one antenna 1, 1 1 , 12 and/ or the high frequency interface 2. The processor 4 is connected to the radio frequency chains or transceivers TRX.

According to a further embodiment, the user equipment 100 includes a selector unit 5 configured for selective transmission or reception of high frequency signals on the high frequency interface 2 and transmission or reception of radio signals on the at least one antenna 1, 1 1 , 12. The selector unit 5 is preferably configured for enabling selecting to transmit or receive a signal on one or both of the at least one antenna 1 , 1 1 , 12 and the high frequency interface 2.

According to a further embodiment, the user equipment 100 includes two or more antennas 1 , 1 1 , 12. Moreover, the selector 5 is adapted to deselect one of the two or more antennas 1 , 1 1, 12 and instead select the high frequency interface 2.

It is, according to a further embodiment, possible to utilize the two or more antennas in combination with the high frequency interface to enable antenna diversity benefits, or MIMO benefits depending on the situation or specific criteria for a particular service.

With reference to Figure 4, embodiments of a hands-free device 200 or satellite equipment 200 to a user equipment 100 will be described. The wireless hands-free device 200 or satellite device for a user equipment in a communication system includes an antenna 10 configured for communication with a base station, and a high frequency interface 20 e.g. optical interface configured for communication with at least the user equipment 100. In addition, the hands-free device 200 includes a converter 30 configured for converting a radio signal received from a base station on the antenna 10 to a high frequency signal for transmission over the high frequency interface 20 to the user equipment, or for converting a high frequency signal received from the user equipment on the high frequency interface 20 to a radio signal for transmission to the base station on the antenna 10, wherein the high frequency signal comprises a representation of said radio signal.

In particular, the converter 30 simply performs the act of directly mapping a received radio signal into a high frequency signal without having to digitally demodulate, decode, code and digitally modulate the radio signal first. Consequently, on transmit, the received high frequency signal from the mobile device at the hands-free can be demodulated and retransmitted to the base station directly on a radio link.

The antenna 10 and high frequency interface 20 of the hands-free device 200 can be configured to be always active, or to be in a latent mode awaiting an activation signal from the user equipment or base station.

With reference to both Figure. 3 and Figure 4 a communication system for MIMO transmission and reception according to the present invention can be described. If a hands-free device 200 with the extra antenna 10 is in the vicinity, the user equipment e.g. cell phone 100 may choose to use the external antenna 10 in the hands-free device 200 instead of or together with one or more of its own antennas 1, 1 1 , 12. The radio frequency transceivers TRX and all the base band processing are located in the cell phone 100. The switching between antennas is performed on radio frequency and, since the high frequency interface 2, 20 e.g. radio frequency over wireless optical does not introduce any significant extra delays, the external antenna 10 in the hands-free device 200 is seen by a base band processing unit just as an ordinary antenna.

With reference to Figure 6, a basic embodiment of a method of receiving signals in a user equipment will be described. Initially, at least one radio signal is received S 10 on at least a first antenna in the user equipment. In addition, a high frequency signal is received S20 over a high frequency interface in the user equipment. The high frequency signal typically comprises a representation of the same radio signal as the one received on the first antenna. However, it is equally possible that the two radio signals are different, especially for the case of providing antenna diversity. Subsequently the received high frequency signal is converted S30 into the radio signal (or another radio signal), and the radio signal from the at least a first antenna, and the converted high frequency signal are selectively and jointly processed S50 to decode the radio signal. According to a farther embodiment, the processing step S50 comprises actively selecting and jointly processing both the converted high frequency signal and the received radio signal. However, according to other embodiments, the processing step S50 comprises deselecting the at least one antenna and instead selecting the high frequency interface for receiving signals.

The at least one radio signal received from the base station can comprise a MIMO or SIMO signal. A first signal is received by the antenna on the use equipment e.g. cell phone. A second signal is picked up by the antenna on the hands-free device, directly converted to an optical signal, and transferred via an optical interface to the cell phone. The optical signal is then received by the cell phone, converted back to radio frequency, demodulated, and decoded by the radio receiver in the cell phone. The two received signals are then combined using MIMO or diversity reception techniques in the processor.

With reference to Figure 7, an embodiment of a method of transmitting signals in a user equipment according to the present invention will be described. Initially at least one radio signal is provided S I 00 in the user equipment. The signal is converted S200 into a high frequency e.g. optical signal representative of the provided radio signal. Finally, the two signals are selectively transmitted S300, S400 on the at least one antenna and/ or the high frequency interface. According to a particular embodiment, the step of selective transmission S300, S400 comprises actively selecting and jointly transmitting both or one of the converted high frequency signal and the provided radio signal. According to a further embodiment, the step of providing the at least one radio signal S I 00 comprises splitting at least one radio signal into at least two branches, preferably utilizing one of diversity or MIMO processing.

With reference to Figure 8, an embodiment of a method of relaying communication signals in a wireless hands free device or a satellite device to a user equipment will be described. Initially, a high frequency signal is received S410 from a user equipment over a high frequency interface in the device. The high frequency signal comprises a representation of a radio signal. Subsequently, the received high frequency signal is converted, in a converter unit, into the radio signal. Finally, the radio signal is transmitted S600 to a base station from at least one antenna in the device.

In a further embodiment and in a corresponding manner, with reference to Figure 9, a radio signal is received S410' from a base station. The received signal is then converted S500', in a converter unit, into a high frequency signal, which is subsequently transmitted to a user equipment via a high frequency interface in the device.

For both the above described methods, the converting step S500, S500' typically comprises a simple and straightforward modulation/ demodulation of the received signal. However, according to a further embodiment the converting step comprises frequency conversion.

In order to provide a more complete understanding of the inter-relationship between the methods described for the user equipment, and the methods described for the hands-free device, a few embodiments will be described with reference to Figure 10, Figure 1 1 , and Figure 12.

According to the receiving embodiment depicted in Figure 10, at least one radio signal is received S 10 at least one antenna in a user equipment. At the same time, or at least on close timing with said receiving step S 10, the same radio signal or another radio signal is received S410' at an antenna in a wireless hands-free device or some other satellite device associated with the user equipment. The radio signal received in the hands-free device is then subjected to conversion and converted S500' into a high frequency signal which is subsequently transferred or transmitted S600' to a user equipment via a high frequency interface in the hands-free device. Then the high frequency signal is received S20 in the user equipment and converted S30 into a radio signal. Finally, MIMO or diversity processing is performed selectively and jointly on the radio signals, either both or only one of the signals. With reference to Figure 11, an embodiment of a receiving method in a communication system will be described. A first signal is received S10 in a mobile device e.g. user equipment. In coordination, or near in time, a second signal is picked up S410'at a hands-free device. The second signal is converted S500' into an optical signal e.g. high frequency signal, and transferred S600' to the mobile device via a high frequency e.g. optical interface. The transferred high frequency signal is received and converted S20, S30 into a radio signal in the mobile device. Finally, MIMO /diversity processing is performed on the first and second signal, either both or one of them.

With reference to Figure 12 a flowchart describing the process of transmitting a MIMO or MISO signal using the present invention will be described. A radio signal is provided SI 00 in a user equipment e.g. mobile device; this is preferably enabled by splitting the signal in two by a processor in the mobile device using MIMO or transmit diversity techniques. The two signals are converted to radio signals by two parallel radio transmitters. One of the signals is then converted S200 to an optical signal and transferred via an optical interface S400 to a hands-free device, where the optical signal is converted back S500 to a radio signal and retransmitted S600 via the external antenna in the hands-free device into the air, preferably to a base station. The other provided split signal is transmitted S300 via the cell phone's own antenna into the air.

Note that the radio frequency over wireless optical link will not introduce any additional delays in the communication path from cell phone via hands-free to base station and vice versa. Therefore, the radio frequency over wireless optical is completely transparent for both the cell phone and the base station. The present disclosure is not limited to the number of antennas mentioned in the previously described embodiments, neither in the cell phone nor in the wireless hands-free. Consequently, it could prove beneficial to implement more than one antenna in the cell phone or wireless hands-free device to provide further diversity benefits.

The present disclosure is further not limited to wireless hands-free devices, but the extra antenna and the radio frequency over wireless optical can be implemented in any auxiliary or satellite external device associated with the user equipment. As an example, the satellite device can comprise a standalone unit to be placed in the close vicinity of a user's workplace, such as a table mounted unit to be placed on a desk. Other examples include configuring the satellite unit as an integrated part of a private or public transportation vehicle or building, or even as part of a personal accessory such as a piece of jewelry or clothing. In addition, the number of external or satellite devices with additional antennas and radio frequency over wireless optical links can be more than one. According to yet a further embodiment, the satellite device could be configured to support a plurality of nearby user equipment. In a corresponding manner, a user equipment can be configured to actively search for and utilize an external antenna in a nearby wireless hands-free or satellite device associated with another user equipment.

One advantage of the present disclosure compared to prior art solutions for using an extra external antenna is that no extra radio chain or base band processing has to be implemented close to the external antenna. This reduces the cost, saves energy, and decrease the latency compared to methods that require demodulating and modulating of a signal.

A further advantage with utilizing an extra external antenna is that the communication link between a mobile device and a base station gets improved. The improved communication link between the mobile device and the base station is due to many reasons. One reason is that in mobile devices, where the physical structure is small, antennas are by necessity placed in close vicinity to each other. This causes increased signal correlation and reduced antenna efficiency, which both tend to degrade MIMO capacity between the base station and the mobile device. When using an additional antenna integrated in a hands-free that has a large spatial distance from the mobile device and therefore experience small signal correlation and mutual coupling to the antennas in the mobile device, the MIMO capacity can be largely increased.

Another advantage with the methods and arrangements of the present disclosure is that when a user is holding a cell phone in browse mode, the hand of the user will cover parts of the antennas in the cell phone, which will decrease the antenna efficiency and therefore reduce the MIMO capacity. But if the extra external antenna in a hands-free device is used, there is no hand that reduces the efficiency, so the user will get much higher SINR and therefore increase the capacity. The embodiments described above are to be understood as a few illustrative examples of the present invention. It will be understood by those skilled in the art that various modifications, combinations and changes may be made to the embodiments without departing from the scope of the present invention. In particular, different part solutions in the different embodiments can be combined in other configurations, where technically possible. The scope of the present invention is, however, defined by the appended claims. REFERENCES

[1] "Virtual Multiple Antenna (VMAT)", US Patent Application Publication US 2008/0318584 Al . [2] htt : / / live . psu.edu / story/44147

[3] Receive diversity and multiple input multiple output (MIMO) using multiple mobile devices, US Patent Application US 2009/0170455

Claims

1. A user equipment (100) in a communication system, characterized by at least one antenna (1) configured for receiving and transmitting radio signals;

at least one high frequency interface (2) configured for receiving and transmitting high frequency signals;

a converter (3) configured for converting radio signals to high frequency signals and converting high frequency signals to radio signals;

a processor (4) configured for processing signals for reception and transmission on said at least one antenna (1) and/ or said high frequency interface (2).

2. The user equipment (100) according to claim 1 , characterized by said processor (4) being configured for jointly processing signals for reception and transmission on said at least one antenna (1) and/ or said high frequency interface (2).

3. The user equipment (100) according to claim 1 , characterized by at least one selector (5) configured for selective transmission or reception of high frequency signals on said at least one high frequency interface (2) and transmission or reception of radio signals on said at least one antenna (1).

4. The user equipment (100) according to claim 1 , characterized by said at least one high frequency interface (2) comprising an optical interface.

5. A wireless hands-free device (200) or satellite device for a user equipment in a communication system, characterized by

an antenna (10) configured for communication with a base station;

at least one high frequency interface (20) configured for communication with at least said user equipment;

a converter (30) configured for converting a radio signal received on said antenna (10) to a high frequency signal for transmission over said high frequency interface (20), or for converting a high frequency signal received on said high frequency interface (20) to a radio signal for transmission on said antenna (10), wherein said high frequency signal comprises a representation of said radio signal.

6. The device according to claim 5, wherein said device (200) is integrated in a piece of furniture, a vehicle, piece of a building.

7. The device according to claim 5, wherein said device (200) is configured to communicate with a plurality of user equipments (100) over said high frequency interface.

8. The device according to claim 5, characterized in that said converter (30) is configured to directly modulate / demodulate said radio signal to / from said high frequency signal without introducing any delay.

9. The device according to claim 5, characterized by said at least one high frequency interface (20) comprising an optical interface.

10. A method of receiving signals in a user equipment in a communication system, characterized by

in said user equipment:

receiving (S 10) at least one radio signal on at least a first antenna;

receiving (S20) a high frequency signal over a high frequency interface, said high frequency signal comprising a representation of said radio signal; converting (S30) said received high frequency signal into said radio signal; selectively and jointly processing (S50) said radio signal from said at least a first antenna, and said converted high frequency signal to decode said radio signal.

11. The method according to claim 10, characterized by actively selecting and jointly processing both said converted high frequency signal and said received radio signal.

12. A method of transmitting signals in a user equipment in a communication system, characterized by:

in said user equipment:

providing (SI 00) at least one radio signal;

converting (S200) said radio signal into a high frequency signal representative of said radio signal;

selectively transmitting (S400) said high frequency signal over at least one high frequency interface and/ or transmitting (S300) said radio signal on at least one antenna.

13. The method according to claim 12, characterized by actively selecting and jointly transmitting both said converted high frequency signal and said provided radio signal.

14. The method according to claim 12, characterized by said step of providing at least one radio signal (SI 00) comprising splitting at least one radio signal into at least two branches.

15. The method according to claim 14, characterized by said step of splitting said at least one radio signal into at least two branches comprising utilizing one of diversity or MIMO processing.

16. A method of relaying signals in a wireless hands-free device or satellite device to a user equipment in a communication system, characterized by in said device:

receiving (S410) a high frequency signal representative of a radio signal over at least one high frequency interface;

converting (S500) said received high frequency signal into said radio signal;

transmitting (S600) said radio signal from at least one antenna.

17. A method of relaying signals in a wireless hands-free device or satellite device to a user equipment in a communication system, characterized by in said device:

receiving (S410') a radio signal on at least one antenna;

converting (S500⁵) said radio signal into a high frequency signal representative of said radio signal;

transmitting (S600') said high frequency signal over at least one high frequency interface.