PATENT DOCUMENT

Publication Number: US-11005544-B2
Application Number: US-201615137021-A
Country: US
Kind Code: B2

Title: Communication device and method for performing radio communication

Abstract:
A communication device is described comprising a first antenna, a second antenna and a third antenna; a first transceiver configured to communicate using at least the first antenna; a second transceiver configured to communicate using at least the second antenna; and a controller configured to determine whether the third antenna is to be used by the first transceiver or the second transceiver based on a selection criterion and configured to control the first transceiver to communicate using the first antenna and the third antenna if the controller has determined that the third antenna is to be used by the first transceiver and to control the second transceiver to communicate using the second antenna and the third antenna if the controller has determined that the third antenna is to be used by the second transceiver.

Claims:
The invention claimed is: 
     
       1. A communication device comprising:
 a first transceiver configured to communicate according to a first radio access technology (RAT) using at least a first antenna; 
 a second transceiver configured to communicate according to a second RAT using at least a second antenna; 
 a controller configured to:
 receive, from the second transceiver, a request for communication of a streaming type of data; 
 in response to receiving said request, transmitting a report to a base station while a rank of a MIMO channel between the first transceiver and the base station is equal to two, wherein the report indicates that the rank of the MIMO channel is one, wherein the report is transmitted via the first transceiver; and 
 in response to transmitting the report, controlling the first transceiver to receive a downlink transmission of rank 1 from the base station using the first antenna, and switching a third antenna from the first transceiver to the second transceiver, to enable the second transceiver to perform rank 2 MIMO communication using the second antenna and third antenna. 
 
 
     
     
       2. The communication device of  claim 1 , wherein the first RAT is 3GPP Long Term Evolution, wherein the second RAT is WiFi. 
     
     
       3. The communication device of  claim 1 , wherein the streaming type of data is streaming video data. 
     
     
       4. The communication device of  claim 1 , wherein, when the controller receives said request, the first transceiver is engaged in a rank 2 MIMO connection using the first and third antennas. 
     
     
       5. The communication device of  claim 4 , wherein, when the controller receives said request, the first transceiver is conducting a voice call using the first and third antennas. 
     
     
       6. The communication device of  claim 1 , wherein the communication device is a wireless user equipment device. 
     
     
       7. The communication device of  claim 1 , wherein said controlling and said switching support a transfer of the streaming type of data from the base station to a wireless device, via the communication device. 
     
     
       8. The communication device of  claim 1 , wherein said communication device further comprises the first, second and third antennas. 
     
     
       9. The communication device of  claim 8 , further comprising circulators, wherein each of the antennas is coupled to a respective one of the circulators. 
     
     
       10. An apparatus comprising processing circuitry, wherein the processing circuitry is configured to cause a user equipment device to:
 communicate, via a first transceiver, according to a first radio access technology (RAT) using at least a first antenna; 
 communicate, via a second transceiver, according to a second RAT using at least a second antenna; 
 receive, from the second transceiver, a request for communication of a streaming type of data; 
 in response to receiving said request, transmit a report to a base station while a rank of a MIMO channel between the first transceiver and the base station is equal to two, wherein the report indicates that the rank of the MIMO channel is one, wherein the report is transmitted via the first transceiver; and 
 in response to transmitting the report, control the first transceiver to receive a downlink transmission of rank 1 from the base station using the first antenna, and switch a third antenna from the first transceiver to the second transceiver, to enable the second transceiver to perform rank 2 MIMO communication using the second antenna and third antenna. 
 
     
     
       11. The apparatus of  claim 10 , wherein the first RAT is 3GPP Long Term Evolution, wherein the second RAT is WiFi. 
     
     
       12. The apparatus of  claim 10 , wherein the streaming type of data is streaming video data. 
     
     
       13. The apparatus of  claim 10 , wherein, when the request is received, the first transceiver is engaged in a rank 2 MIMO connection using the first and third antennas. 
     
     
       14. The apparatus of  claim 13 , wherein, when the request is received, the first transceiver is conducting a voice call using the first and third antennas. 
     
     
       15. The apparatus of  claim 10 , wherein said controlling and said switching support a transfer of the streaming type of data from the base station to a wireless device, via the user equipment device. 
     
     
       16. A non-transitory memory medium storing program instructions, wherein the program instructions, when executed by processing circuitry, cause a user equipment (UE) device to perform operations comprising:
 communicating, via a first transceiver, according to a first radio access technology (RAT) using at least a first antenna; 
 communicating, via a second transceiver, according to a second RAT, using at least a second antenna; 
 receiving, from the second transceiver, a request for communication of a streaming type of data; 
 in response to receiving said request, transmitting a report to a base station while a rank of a MIMO channel between the first transceiver and the base station is greater than one, wherein the report indicates that the rank of the MIMO channel is one, wherein the report is transmitted via the first transceiver; and 
 in response to transmitting the report, controlling the first transceiver to receive a downlink transmission of rank 1 from the base station using the first antenna, and switching a third antenna from the first transceiver to the second transceiver, to enable the second transceiver to perform rank N MIMO communication using at least the second antenna and third antenna, wherein N is greater than one. 
 
     
     
       17. The non-transitory memory medium of  claim 16 , wherein, when the request is received, the first transceiver is engaged in a rank 2 MIMO connection using the first and third antennas.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. Ser. No. 14/062,982, filed Oct. 25, 2013, which claims the benefit of U.S. provisional patent application No. 61/827,029, filed May 24, 2013, all of which are hereby incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     Embodiments described herein generally relate to communication devices and methods for performing radio communication. 
     BACKGROUND 
     Today&#39;s mobile communication devices (such as smartphones, tablets, notebooks etc.) may support multiple Radio Access Technologies (RATs) like WLAN (Wireless Local Area Network), Bluetooth, GPS (Global Positioning System), GSM (Global System for Mobile Communications), UMTS (Universal Mobile Telecommunication System), LTE (Long Term Evolution) etc. For the reception and transmission of wireless signals using a certain RAT a communication device needs an antenna. For high-data speed or improved reception with technologies like Receive Diversity or Transmit Diversity or MIMO (Multiple Input Multiple Output) even multiple antennas may be needed for a certain RAT, e.g. LTE or WLAN. 
     However, the available space in a mobile communication device is typically very limited and often not sufficient to place a higher number of antennas. A reduction of the size of the antennas may not be possible or may be undesirable since it may reduce the antennas&#39; performance significantly. Furthermore, each antenna that is incorporated in a mobile communication device generates additional cost during production of the mobile communication device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings, like reference characters generally refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the following description, various aspects are described with reference to the following drawings, in which: 
         FIG. 1  shows a communication arrangement. 
         FIG. 2  shows a communication device. 
         FIG. 3  shows a flow diagram illustrating a method for performing radio communication. 
         FIG. 4  shows a transceiver arrangement with an LTE transceiver and a WLAN transceiver sharing an antenna. 
         FIG. 5  shows a signal diagram illustrating a scenario in which a shared antenna is switched from LTE to WLAN for a period of unknown length. 
         FIG. 6  shows a signal diagram in which a shared antenna is switched from LTE to WLAN for a short period of known length. 
         FIG. 7  shows a signal diagram in which a shared antenna is switched from LTE to WLAN for a very short period. 
         FIG. 8  shows a communication arrangement in a tethering scenario. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     The following detailed description refers to the accompanying drawings that show, by way of illustration, specific details and aspects of this disclosure in which the invention may be practiced. Other aspects may be utilized and structural, logical, and electrical changes may be made without departing from the scope of the invention. The various aspects of this disclosure are not necessarily mutually exclusive, as some aspects of this disclosure can be combined with one or more other aspects of this disclosure to form new aspects. 
       FIG. 1  shows a communication arrangement  100 . 
     The communication arrangement  100  includes a mobile communication device  101  (such as a smartphone, a tablet, a notebooks etc) which supports two (or more) radio access technologies (RATs), in this example LTE (Long Term Evolution) and WiFi (or, in other words, WLAN). For this, the mobile communication device  101 , also referred to as mobile terminal, includes a first transceiver  102 , in this example an LTE transceiver and a second transceiver  103 , in this example a WiFi transceiver. 
     The mobile communication device  101  further comprises a plurality of antennas  104 . By means of one or more of the antennas  104 , the LTE transceiver  102  may communicate with an LTE base station  105  and the WiFi transceiver  103  may communicate with a WLAN (Wireless Local Area Network) access point  106 . 
     It should be noted that LTE and WiFi are only examples and other RATs may be used such as UMTS (Universal Mobile Telecommunications System), GSM (Global System for Mobile Communications), Bluetooth, GPS (Global Positioning System) etc. 
     The RATs, in this example LTE and WiFi may support technologies that require the usage of more than one antenna, for example MIMO (Multiple Input Multiple Output). To provide both transceivers  102 ,  103  with a sufficient number for such technologies while not including a high number of antennas, which may be undesirable, e.g. due to space restrictions, an antenna may be used (uncontrolled) in parallel by a plurality of RATs. However, due to the possible interaction between the signals of the different RATs and the lack of tuning the antenna to a specific RAT the reception performance may be degraded. 
     As described in the following, according to one example, a communication device provided in which one or more antennas may be shared between RATs (which each request multiple antennas) by switching it between the RATs in a controlled manner. RATs such as LTE and WiFi typically require multiple antennas only for high-speed data reception or transmission or under bad radio conditions. However, it is unlikely that multiple RATs do a high-speed data reception or transmission at the same time. In case that multiple RATs experience degrading radio conditions a priority decision could be taken which RAT is more important and is assigned a shared antenna. 
       FIG. 2  shows a communication device  200 . 
     The communication device  200  comprises a first antenna  201 , a second antenna  202  and a third antenna  203 , a first transceiver  204  configured to communicate using at least the first antenna  201  and a second transceiver  205  configured to communicate using at least the second antenna  202 . 
     The communication device  200  further comprises a controller  206  configured to determine whether the third antenna  203  is to be used by the first transceiver  204  or the second transceiver  205  based on a selection criterion and configured to control the first transceiver  204  to communicate using the first antenna  201  and the third antenna  203  if the controller  206  has determined that the third antenna  203  is to be used by the first transceiver  204  and to control the second transceiver  205  to communicate using the second antenna  202  and the third antenna  203  if the controller  206  has determined that the third antenna  203  is to be used by the second transceiver  205 . 
     In other words, an antenna (in this example the third antenna) may be shared between different transceivers (e.g. operating according to different RATs) in the sense that it is decided based on a certain criterion which transceiver may use the antenna (in addition to the one or more antennas that are assigned to the transceiver anyway). The criterion may for example be based on a required quality of the communication of the first transceiver and the communication of the second transceiver (e.g. a required throughput, robustness, Quality of Service, latency etc.), on a priority of the first transceiver and a priority of the second transceiver and/or the current radio conditions that the transceiver experiences. For example, the transceiver which experiences the worse radio conditions is assigned with the shared antenna. Worse radio conditions may for example mean a higher risk of a lost communication connection or a higher bit error rate or packet error rate, a lower signal-to-noise ratio etc. 
     The communication device  200  for example carries out a method as illustrated in  FIG. 3 . 
       FIG. 3  shows a flow diagram  300 . 
     The flow diagram  300  illustrates a method for performing radio communication, for example carried out by a controller of a communication device. 
     In  301 , the controller determines whether a third antenna of the communication device which comprises a first antenna, a second antenna and the third antenna is to be used by a first transceiver or a second transceiver of the communication device based on a selection criterion. 
     In  302 , the controller controls the first transceiver to communicate using the first antenna and the third antenna if the third antenna is to be used by the first transceiver. 
     In  302 , the controller controls the second transceiver to communicate using the second antenna and the third antenna if the third antenna is to be used by the second transceiver. 
     The following examples pertain to further embodiments. 
     Example 1, as described with respect to  FIG. 2 , is a communication device comprising a first antenna, a second antenna and a third antenna; a first transceiver configured to communicate using at least the first antenna; a second transceiver configured to communicate using at least the second antenna; and a controller configured to determine whether the third antenna is to be used by the first transceiver or the second transceiver based on a selection criterion and configured to control the first transceiver to communicate using the first antenna and the third antenna if the controller has determined that the third antenna is to be used by the first transceiver and to control the second transceiver to communicate using the second antenna and the third antenna if the controller has determined that the third antenna is to be used by the second transceiver. 
     In Example 2, the subject matter of Example 1 can optionally include the first transceiver being configured to communicate according to a first radio access technology and the second transceiver being configured to communicate according to a second radio access technology different from the first radio access technology. 
     In Example 3, the subject matter of Examples 1-2 can optionally include the first transceiver including a first baseband circuit and the second transceiver including a second baseband circuit. 
     In Example 4, the subject matter of Examples 1-3 can optionally include the controller being configured to control the first transceiver to communicate using the first antenna and the third antenna and the second transceiver to communicate simultaneously using the second antenna if the controller has determined that the third antenna is to be used by the first transceiver and to control the second transceiver to communicate using the second antenna and the third antenna and the first transceiver to communicate simultaneously using the first antenna if the controller has determined that the third antenna is to be used by the second transceiver. 
     In Example 5, the subject matter of Examples 1-4 can optionally include the controller being configured to determine whether the third antenna is to be used by the first transceiver or the second transceiver based on a quality requirement of the communication of the first transceiver and a quality requirement of the communication of the second transceiver. 
     In Example 6, the subject matter of Example 5 can optionally include the controller being configured to determine that the third antenna is to be used by the first transceiver if the quality requirement of the communication of the first transceiver is higher than the quality requirement of the communication of the second transceiver and to determine that the third antenna is to be used by the second transceiver if the quality requirement of the communication of the second transceiver is higher than the quality requirement of the communication of the first transceiver. 
     In Example 7, the subject matter of Examples 5-6 can optionally include the quality requirement being a throughput requirement or a robustness requirement or a combination of both. 
     In Example 8, the subject matter of Examples 1-7 can optionally include the controller being configured to determine whether the third antenna is to be used by the first transceiver or the second transceiver based on a priority of the communication of the first transceiver and a priority of the communication of the second transceiver. 
     In Example 9, the subject matter of Examples 1-8 can optionally include the controller being configured to determine whether the third antenna is to be used by the first transceiver or the second transceiver based on radio conditions of the communication of the first transceiver and based on radio conditions of the communication of the second transceiver. 
     In Example 10, the subject matter of Example 9 can optionally include the controller being configured to determine that the third antenna is to be used by the first transceiver if the radio conditions of the communication of the first transceiver are worse than the radio conditions of the communication of the second transceiver and to determine that the third antenna is to be used by the second transceiver if the radio conditions of the communication of the second transceiver are worse than the radio conditions of the communication of the first transceiver. 
     In Example 11, the subject matter of Examples 1-10 can optionally include the controller being configured to control the first transceiver to perform a MIMO communication using the first antenna and the third antenna if the controller has determined that the third antenna is to be used by the first transceiver and to control the second transceiver to perform a MIMO communication using the second antenna and the third antenna if the controller has determined that the third antenna is to be used by the second transceiver. 
     In Example 12, the subject matter of Examples 1-11 can optionally include the communication device being a communication terminal. 
     In Example 13, the subject matter of Examples 1-12 can optionally include the communication device being a subscriber terminal of a mobile cellular radio communication system and the first transceiver is configured to communicate with a base station of the mobile cellular radio communication system. 
     In Example 14, the subject matter of Examples 1-13 can optionally include the second transceiver being configured to communicate with an access point of a wireless local area network. 
     In Example 15, the subject matter of Examples 1-14 can optionally include the controller being configured to control the first transceiver to perform downlink communication using the first antenna and the third antenna if the controller has determined that the third antenna is to be used by the first transceiver and to control the second transceiver to perform downlink communication using the second antenna and the third antenna if the controller has determined that the third antenna is to be used by the second transceiver. 
     In Example 16, the subject matter of Examples 1-15 can optionally include the controller being configured to control the first transceiver to perform downlink communication using the first antenna and the third antenna and the second transceiver to simultaneously perform downlink communication using the second antenna if the controller has determined that the third antenna is to be used by the first transceiver and to control the second transceiver to perform downlink communication using the second antenna and the third antenna and the first transceiver to simultaneously perform downlink communication using the first antenna if the controller has determined that the third antenna is to be used by the second transceiver. 
     In Example 17, the subject matter of Examples 1-16 can optionally include the controller being configured
         to determine whether the third antenna is to be used by the first transceiver or the second transceiver for downlink communication;   to control the first transceiver to perform downlink communication using the first antenna and the third antenna if the controller has determined that the third antenna is to be used by the first transceiver for downlink communication;   to control the second transceiver to perform downlink communication using the second antenna and the third antenna if the controller has determined that the third antenna is to be used by the second transceiver for downlink communication;   to determine whether the third antenna is to be used by the first transceiver or the second transceiver for uplink communication;   to control the first transceiver to perform uplink communication using the first antenna and the third antenna if the controller has determined that the third antenna is to be used by the first transceiver for uplink communication; and   to control the second transceiver to perform uplink communication using the second antenna and the third antenna if the controller has determined that the third antenna is to be used by the second transceiver for uplink communication.       

     In Example 18, the subject matter of Examples 1-17 can optionally include the first transceiver being configured to communicate with a first device and the second transceiver being configured to communicate with a second device different from the first device. 
     In Example 19, the subject matter of Examples 1-18 can optionally include the first device being a base station of a cellular mobile communication network. 
     In Example 20, the subject matter of Examples 1-19 can optionally include the second device being a communication terminal and the communication device being configured to provide the second device with a communication connection to the cellular mobile communication network by means of the first transceiver and the second transceiver. 
     Example 21, as described with respect to  FIG. 3 , is a method for performing radio communication comprising determining whether a third antenna of a communication device comprising a first antenna, a second antenna and the third antenna is to be used by a first transceiver or a second transceiver of the communication device based on a selection criterion; controlling the first transceiver to communicate using the first antenna and the third antenna if the third antenna is to be used by the first transceiver; and controlling the second transceiver to communicate using the second antenna and the third antenna if the third antenna is to be used by the second transceiver. 
     In Example 22, the subject matter of Example 21 can optionally include the first transceiver communicating according to a first radio access technology and the second transceiver communicating according to a second radio access technology different from the first radio access technology. 
     In Example 23, the subject matter of Examples 21-22 can optionally include the first transceiver including a first baseband circuit and the second transceiver including a second baseband circuit. 
     In Example 24, the subject matter of Examples 21-23 can optionally include controlling the first transceiver to communicate using the first antenna and the third antenna and the second transceiver to communicate simultaneously using the second antenna if the third antenna is to be used by the first transceiver and controlling the second transceiver to communicate using the second antenna and the third antenna and the first transceiver to communicate simultaneously using the first antenna if the third antenna is to be used by the second transceiver. 
     In Example 25, the subject matter of Examples 21-24 can optionally include determining whether the third antenna is to be used by the first transceiver or the second transceiver based on a quality requirement of the communication of the first transceiver and a quality requirement of the communication of the second transceiver. 
     In Example 26, the subject matter of Example 25 can optionally include determining that the third antenna is to be used by the first transceiver if the quality requirement of the communication of the first transceiver is higher than the quality requirement of the communication of the second transceiver and to determine that the third antenna is to be used by the second transceiver if the quality requirement of the communication of the second transceiver is higher than the quality requirement of the communication of the first transceiver. 
     In Example 27, the subject matter of Examples 25-26 can optionally include the quality requirement being a throughput requirement or a robustness requirement or a combination of both. 
     In Example 28, the subject matter of Examples 21-27 can optionally include determining whether the third antenna is to be used by the first transceiver or the second transceiver based on a priority of the communication of the first transceiver and a priority of the communication of the second transceiver. 
     In Example 29, the subject matter of Examples 21-28 can optionally include determining whether the third antenna is to be used by the first transceiver or the second transceiver based on radio conditions of the communication of the first transceiver and based on radio conditions of the communication of the second transceiver. 
     In Example 30, the subject matter of Example 29 can optionally include determining that the third antenna is to be used by the first transceiver if the radio conditions of the communication of the first transceiver are worse than the radio conditions of the communication of the second transceiver and determining that the third antenna is to be used by the second transceiver if the radio conditions of the communication of the second transceiver are worse than the radio conditions of the communication of the first transceiver. 
     In Example 31, the subject matter of Examples 21-30 can optionally include controlling the first transceiver to perform a MIMO communication using the first antenna and the third antenna if the third antenna is to be used by the first transceiver and controlling the second transceiver to perform a MIMO communication using the second antenna and the third antenna if the third antenna is to be used by the second transceiver. 
     In Example 32, the subject matter of Examples 21-31 can optionally include the communication device being a communication terminal. 
     In Example 33, the subject matter of Examples 21-32 can optionally include the communication device being a subscriber terminal of a mobile cellular radio communication system and the first transceiver being configured to communicate with a base station of the mobile cellular radio communication system. 
     In Example 34, the subject matter of Examples 21-33 can optionally include the second transceiver being configured to communicate with an access point of a wireless local area network. 
     In Example 35, the subject matter of Examples 21-34 can optionally include controlling the first transceiver to perform downlink communication using the first antenna and the third antenna if the third antenna is to be used by the first transceiver and controlling the second transceiver to perform downlink communication using the second antenna and the third antenna if the third antenna is to be used by the second transceiver. 
     In Example 36, the subject matter of Examples 21-35 can optionally include controlling the first transceiver to perform downlink communication using the first antenna and the third antenna and the second transceiver to simultaneously perform downlink communication using the second antenna if the third antenna is to be used by the first transceiver and controlling the second transceiver to perform downlink communication using the second antenna and the third antenna and the first transceiver to simultaneously perform downlink communication using the first antenna if the third antenna is to be used by the second transceiver. 
     In Example 37, the subject matter of Examples 21-36 can optionally include
         determining whether the third antenna is to be used by the first transceiver or the second transceiver for downlink communication   controlling the first transceiver to perform downlink communication using the first antenna and the third antenna if the third antenna is to be used by the first transceiver for downlink communication   controlling the second transceiver to perform downlink communication using the second antenna and the third antenna if the third antenna is to be used by the second transceiver for downlink communication   determining whether the third antenna is to be used by the first transceiver or the second transceiver for uplink communication;   controlling the first transceiver to perform uplink communication using the first antenna and the third antenna if the third antenna is to be used by the first transceiver for uplink communication; and   controlling the second transceiver to perform uplink communication using the second antenna and the third antenna if the third antenna is to be used by the second transceiver for uplink communication.       

     In Example 38, the subject matter of Examples 21-37 can optionally include the first transceiver communicating with a first device and the second transceiver communicating with a second device different from the first device. 
     In Example 39, the subject matter of Examples 21-38 can optionally include the first device being a base station of a cellular mobile communication network. 
     In Example 40, the subject matter of Examples 21-39 can optionally include the second device being a communication terminal and the communication device providing the second device with a communication connection to the cellular mobile communication network by means of the first transceiver and the second transceiver. 
     Example 41 is a computer readable medium having recorded instructions thereon which, when executed by a processor, make the processor perform a method for performing radio communication according to any one of Examples 21 to 40. 
     In the following, a detailed example is described with reference to the communication arrangement  100  shown in  FIG. 1 , i.e. in which an LTE transceiver  102  and a WiFi transceiver  103  share one of the antennas  104  as both RATs can employ MIMO and support high-speed data. The approach described with reference to  FIGS. 2 and 3  may also be applied to other RATs like Bluetooth, GPS, UMTS, GSM, etc. and extended to more than one shared antenna. 
       FIG. 4  shows a transceiver arrangement  400 . 
     The transceiver arrangement  400  includes an LTE transceiver  401  corresponding to the LTE transceiver  102  and a WiFi transceiver  402  corresponding to the WiFi transceiver  103 . The transceiver arrangement  400  further includes a first antenna  403 , a second antenna  404  and a third antenna  405  which correspond to the antennas  104 . In this example, the first antenna  403  is permanently assigned to the LTE transceiver  401 , the second antenna  404  is permanently assigned to the WiFi transceiver  402  and the third antenna  405  is a shared antenna which may be switched between the LTE transceiver  401  and the WiFi transceiver  402  by means of a switch  406 . Both transceivers  401 ,  402  in this example support 2×2 MIMO (i.e. MIMO with two transmit antennas and two receive antennas) for reception, i.e. for downlink transmission from the base station  105  and the access point  106  to the mobile communication device  101 . 
     The transceiver  401 ,  402  which uses only a single antenna has a slightly degraded performance compared to the other transceiver  401 ,  402  since it may not use two antennas for MIMO. In the following, examples are given how a controller of the mobile communication device  101  may decide to which transceiver  401 ,  402  the shared antenna  405  is assigned such that that both RATs (i.e. transceivers  401 ,  402 ) still can perform well. 
     For example, a controller of the mobile communication device  101  switches the shared antenna  405  by means of controlling the switch  406  according to a smart control mechanism which takes various parameters into account. For example the controller can: 
     a) detect which RAT (in other words which transceiver  401 ,  402 ) requires the higher data rate and assign the shared antenna to this RAT (i.e. the corresponding transceiver  401 ,  402 ). If the mobile communication device  101  has an active WLAN (i.e. WiFi) connection e.g. when its user is at home or at work typically the WLAN connection provides a higher data rate than an LTE connection and the mobile communication device  101  typically uses the WLAN connection, e.g. for video streaming. When the mobile communication device  101  leaves WLAN coverage and for example scans for an accessible WLAN, it may perform a high-speed data transfer (such as video streaming) via LTE and the controller may for this switch the shared antenna  405  to LTE.
 
b) detect that a certain RAT is in degrading radio conditions and assign the shared antenna  405  to this RAT to improve the reception performance of this RAT to keep the corresponding communication connection (i.e. to avoid a connection loss). For example, in the basement of a house the WLAN radio conditions may still be good (perhaps with an WLAN hot spot or repeater) but due to the walls the LTE reception may be degraded and close to a connection loss. In this case, the controller could switch the shared antenna  405  to LTE to keep the connection. On the other hand, when the user leaves his home (or the office or goes in the back of his garden) with his mobile communication device  101  the LTE coverage may be good but the reception of his WLAN may degrade and the controller may decide to switch the shared antenna  405  to WLAN, i.e. to the WLAN transceiver  402 .
 
c) take parameters not originating from the two RATs into account like:
         The traffic types generated by the user like browsing, streaming, voice call, file download and their routing/distribution to the RATs.   User preference (e.g. configured in a menu, possibly with different thresholds like “neutral”, “small preference for RAT 1 or 2”, “high preference”). This preference may also be configured by a network operator (e.g. the LTE communication network operator to which the base station  105  belongs) or the device manufacturer of the mobile communication device  101 , e.g. based on their wishes or capabilities regarding WLAN off-loading.   Location information (provided by a GNSS (Global Navigation Satellite System), WLAN IDs, LTE cell IDs etc.) which might e.g. indicate that WLANs preferred by the user (e.g. a home WLAN, or an office WLAN etc.) are nearby or indicate a location with known bad LTE coverage.   Information (such as the information given in the items above) based e.g. on a historic collection of the mobile communication device  101 , on a central database or on some other information available in the mobile communication device like calendar entries indicating a location.
 
d) take into account the request of a transceiver  401 ,  402  for multiple antennas which may also depend on a dynamic receive or transmit diversity scheme employed by the transceiver which switches on/off (or requests the switching) of antennas, e.g. a diversity antenna based on its own status like good/bad conditions, dedicated packets being received, etc. For example, in case one transceiver  401 ,  402  requests only a single antenna anyway (e.g. because of good conditions), the controller may assign the shared antenna  405  to the other transceiver  401 ,  402 .
       

     The controller may carry out its decision (or determination) also on a combination of the above items and parameters. 
     The controller may also carry out its decision depending on whether the transceivers  401 ,  402  are idle or have an active connection. For example, instead of both transceivers  401 ,  402  having (or establishing) active connections and the controller deciding to which transceiver  401 ,  402  the shared antenna  405  should be assigned for the active connections, the controller may also decide to which transceiver  401 ,  402  the shared antenna  405  should be assigned in case one or both of the transceivers  401 ,  402  are in idle mode. For example, in idle mode typically reception gaps (e.g. in a DRX (discontinuous reception) scheme) are used for a RAT to save power. In this case the controller may switch the shared antenna  405  in a reception gap of one RAT to the other RAT since it is not needed for the RAT with the reception gap. 
     As further example is described in the following. It is assumed that the mobile communication device  101  has a VoLTE voice call via LTE and, in parallel, a WiFi connection. In this case, the controller may differentiate between sporadic WLAN traffic like for browsing and continuous WLAN like for video streaming.
         For sporadic (e.g. browsing) traffic the controller may for example assign the shared antenna  405  to the first transceiver  401 , in other words the VoLTE voice call. The controller may for example switch the shared antenna  405  for short a time period to the second transceiver  402  for the sporadic WLAN traffic. After this time periods, the controller switches the antenna  405  back to LTE for an efficient use of the network capacity.   With a high-rate video streaming via WiFi, for example, the controller may assign the shared antenna to the WiFi transmitter  402  as the low rate VoLTE call can be supported by a single antenna in good radio conditions. However, if the controller detects bad LTE radio conditions it may decide to switch the shared antenna to LTE to avoid a call drop by the enhanced reception offered by the diversity achieved when using a plurality of antennas, to e.g. ensure that the call kept on LTE or is properly handed over to another communication network, e.g. a 2G or 3G communication network.       

     When switching antennas between RATs the controller may consider which transmission schemes the RATs employ. If a RAT (LTE, WLAN etc.) employs e.g. 2×2 MIMO then two antennas are needed for reception to decode the two MIMO streams. However, in practical application the transmission paths of the two antennas may have a high correlation such that only a single MIMO stream may be efficiently supported. To control the transmission the mobile communication device  101  may report a parameter like the rank of the MIMO channel matrix to the transmitter (in this case the base station  105 ). A rank of 2 indicates that two MIMO streams are possible (with two antennas needed) while a rank of 1 indicates the request for a single MIMO stream which can be decoded with a single antenna with a small performance degradation compared to the usage of two antennas. 
     In the following an example is given how this rank reporting can be used by the mobile communication device  101  to configure the MIMO schemes employed at the transmitters of the RATs. As an example, the case of an LTE link running with rank 2 and a WLAN link requesting the shared antenna  405  is used. The RATs may also be reversed or this may also be applied to other RAT combinations. 
     First, a scenario is assumed in which the mobile communication device  101  has a VoLTE voice call via LTE and, in parallel, performs video streaming via WiFi. It is assumed that the radio conditions for LTE are good. The flow is illustrated in  FIG. 5 . 
       FIG. 5  shows a signal diagram  500 . 
     In the signal diagram  500 , time flows from left to right and the assignment of the shared antenna  405  is shown in a first sub-diagram  501 , the MIMO channel matrix rank reported by the LTE transceiver  401  is shown in a second sub-diagram  502  and the MIMO channel matrix rank used by the base station  105  (i.e. the number of streams transmitted) is shown in a third sub-diagram  503 . 
     At first, the shared antenna  405  is assigned to LTE and, due to the good LTE radio conditions, the LTE transceiver  401  reports rank 2 to efficiently use the network capacity. 
     At the start of the video stream the WiFi transceiver  402  requests the shared antenna  405  for a long period of unknown length. 
     Before the shared antenna  405  is switched to WLAN the LTE fakes rank 1 in its report to the base station  105  starting on a first point in time  504  so that the base station  105  changes the transmission to a rank 1 MIMO transmission at a second point in time  505 , which can be received with a single antenna by the LTE receiver. Only then the antenna is switched to WLAN at a third point in time  505 . 
     When the Video stream stops and the WLAN transceiver  402  releases (i.e. no longer uses) the shared antenna  405 , the controller switches the shared antenna  405  back to LTE at a fourth point in time  507 . The LTE transceiver  401  then measures the real rank of the MIMO channel matrix and then starts reporting the correct rank (1 or 2) at a fifth point in time  508 . For example, in case rank 2 is reported the base station  105  continues transmission using two streams at a sixth point in time  509 . 
     As second example, a scenario is assumed in which the WLAN transmitter  402  only requests the shared antenna  405 , e.g. for short browsing data transfer, for a period with a known short length. This is illustrated in  FIG. 6 . 
       FIG. 6  shows a signal diagram  600 . 
     In the signal diagram  600 , time flows from left to right and the assignment of the shared antenna  405  is shown in a first sub-diagram  601 , the MIMO channel matrix rank reported by the LTE transceiver  401  is shown in a second sub-diagram  602  and the MIMO channel matrix rank used by the base station  105  (i.e. the number of streams transmitted) is shown in a third sub-diagram  603 . 
     At first, the shared antenna  405  is assigned to LTE and, due to the good LTE radio conditions, the LTE transceiver  401  reports rank 2 to efficiently use the network capacity. 
     As in the first scenario described with reference to  FIG. 5 , the LTE transceiver  401  fakes rank 1 at a first point in time  604 . The base station  105  changes the transmission to a rank 1 MIMO transmission at a second point in time  605 , which can be received with a single antenna by the LTE receiver. Only then the antenna is switched to WLAN at a third point in time  606 . After the short time period during which the WiFi transceiver  402  requires the shared antenna  405 , the shared antenna  405  is switched back to LTE at a fourth point in time  607 . 
     In contrast to the first scenario described with reference to  FIG. 5 , due to the short time period during which LTE does not have the shared antenna  405 , the LTE transceiver  401  assumes that at the end of the period (when LTE gets back the second antenna) the rank 2 from before is still valid because of an only slowly changing channel and requests the base station  105  to use the rank 2 MIMO transmission scheme already in advance at a fifth point in time  608 . This assumption of the previous rank may for example be done based on a threshold for the length of the gap. This threshold may also e.g. be adapted to speed of the mobile communication device  101 , i.e. how fast the channel changes at the mobile communication device  101 . 
     According to the request by the LTE transceiver  401 , the base station  105  continues transmission using two streams at a sixth point in time  609 . 
     It should be noted that if LTE is already using rank 1 then the faking of rank 1 in the examples described with reference to  FIGS. 5 and 6  is not needed. Furthermore, if the scenario changes in between (e.g. if the LTE connection ends), then only the first or the second part of the schemes as described with respect to  FIGS. 5 and 6  may be used. 
     There may be also scenarios where the shared antenna  405  is used by the second RAT (in this example WiFi) only for a very short time. This could be e.g. short tracking measurements by a GPS/GNSS module after it has an acquisition or short quality measurements by WiFi. The data of the short usage may also be stored to enable offline processing afterwards, without the need of the antenna being active. 
     For such very short antenna switches the overhead of preparing LTE for the switch (e.g. faking rank 1) may be too large compared to the benefit. 
     In such a case the controller may simply switch the shared antenna  405  for the short time period without informing the LTE transceiver  401 . The LTE transceiver  401  in this case experiences a small &amp; short degradation but typically, no severe and long-term effect will be visible because HARQ (Hybrid Automatic Repeat Request) and higher layer retransmissions conceal the impairment. This approach is illustrated in  FIG. 7 . 
       FIG. 7  shows a signal diagram  700 . 
     In the signal diagram  700 , time flows from left to right and the assignment of the shared antenna  405  is shown in a first sub-diagram  701  and the MIMO channel matrix rank reported by the LTE transceiver  401  is shown in a second sub-diagram  702 . 
     At first, the shared antenna  405  is assigned to LTE and, due to the good LTE radio conditions, the LTE transceiver  401  reports rank 2 to efficiently use the network capacity. 
     At a first point in time  703  the controller switches the shared antenna  705  to the WiFi transceiver  402 . The controller decides that, due to the short period during which the shared antenna  705  remains switched to the WiFi transceiver  402 , the LTE transceiver  401  is not informed about this. Accordingly, the LTE transceiver  401  continues to report rank 2. At a second point in time  704 , the shared antenna  705  is switched back to the LTE transceiver  401 . 
     The switch control described above may also be able to control the frequency characterization of the antenna itself. This may be desirable because it may be difficult to create an antenna that covers the full frequency range of both cellular (700 Mhz to 2700 Mhz) and WiFi (2400 Mhz to 5800 Mhz) RATs. The controller may use means to cause an antenna to have an extended frequency range using internal switching of capacitor banks—or any other electrical means which is controlled by the same signal that switches the antenna between the WiFi mode and cellular mode. 
     In the following, a further example is described. One typical application for a smartphone is tethering. With tethering there exists a cellular connection (e.g. according to 3G or LTE) of the smartphone to the Internet. The smartphone gives access to this Internet connection to another device e.g. via cable, Bluetooth, or WiFi. Thus, this other device (e.g. a tablet, ultrabook, notebook etc.) which may have no own cellular connection can have Internet access, for example even outside of WiFi coverage. 
     For applications like HDTV/Video streaming very high data rates are required. To achieve a high data rate, a multiple antenna technology such as MIMO (e.g. 2×2), TX diversity and RX Diversity may be used. In the following, an approach for antenna sharing in a tethering scenario where MIMO is used for data transmission. Specifically, in the approach described in the following, a different number of antennas is used for uplink and downlink to reduce the number of antennas in a mobile phone needed for a high-speed tethering scenario. 
       FIG. 8  shows a communication arrangement  800 . 
     The communication arrangement  800  includes a mobile phone  801  for example corresponding to the mobile communication device  101 , an LTE base station  802  corresponding to the base station  105  and a further communication device  803 . 
     The mobile phone  801  includes an LTE transceiver  804 , a WiFi transceiver  805 , a controller  806  (e.g. implemented by an application processor or a control circuit) and antennas  807 ,  808 ,  809 . A first antenna  807  is permanently assigned to LTE, a second antenna  808  is permanently assigned to WiFi and a third antenna  809  is a shared antenna which may be switched by the controller  806  between LTE and WiFi. 
     In this example, there is a high-speed tethering scenario with the mobile phone  801  (acting as UE (User Equipment) according to LTE) having a LTE 2×2 MIMO (alternatively, this may for example also be 3G/HSDPA MIMO) downlink from the base station  802  for an Internet connection and the mobile phone  801  serving as WiFi access point for tethering to the further device  803 , e.g. a Notebook, with 2×2 MIMO WiFi. 
     In this example, the controller  806  decides to assign the shared antenna  809  to LTE for reception since while the mobile phone  801  only needs to receive a small amount of data from the further device  803 , i.e. has little throughput requirements for WiFi reception, the mobile phone  801  has large throughput requirements for LTE reception. 
     However, for transmission, the shared antenna  809  is assigned to WiFi since it has a high throughput requirement for WiFi transmission while it has a low throughput requirement for LTE transmission. 
     Thus, there is antenna sharing between the cellular link (i.e. the communication connection between the base station  802  and the mobile phone  801 ) and the tethering link (i.e. the communication connection between the further communication device  803  and the mobile phone  801 ). Thus, the number of antennas can be reduced from 4 (2 for 2×2 LTE MIMO and 2 for 2×2 WiFi MIMO) to 3, with still each antenna  807 ,  808 ,  809  serving only one radio technology per direction. In other words, uplink and downlink are considered separately per radio technology and reception and transmission per antenna. 
     Specifically, as the downlink (from the base station  802  to the further device  803 ) requires a much higher data rate (e.g. for HD Video streaming) than the uplink multiple antenna technologies are only applied in the downlink. 
     For the scenario of  FIG. 8 , the downlink includes the downlink connections from the base station  802  to the mobile phone  801  and from the mobile phone  801  to the further device  803 . For the cellular downlink connection, i.e. the downlink connection from the base station  105  to the mobile phone  801 , the mobile phone  801  is the receiver, while for the tethering downlink connection, i.e. the downlink connections from the mobile phone  801  to the further device  803 , it is the transmitter. Accordingly, the mobile phone  801  uses for the cellular downlink connection multiple (here 2) receive antennas, while for the tethering downlink connection the mobile phone  801  uses multiple (here 2) transmit antennas. Considering that for both connections at least one antenna for the reverse (i.e. uplink) direction is needed, the mobile phone  801  may provide the tethering using only 3 antennas instead of 4 with this kind of smart antenna sharing. 
     The antenna transmission and reception signals may be separated by means of circulators  810 . Different frequencies for transmission and reception on one antenna may be used in Frequency Duplex Division (FDD) systems and in Carrier Aggregation scenarios the frequencies may be significantly different. WiFi and e.g. LTE can operate also on similar bandwidth. 
     The approach described with reference to  FIG. 8  may also be applied for more antennas and e.g. higher MIMO schemes (4×2, 4×4 etc.). Further, there may be a matrix connection between the LTE transceiver  804  and the WiFi transceiver  805  and the antennas  807 ,  808 ,  809  (i.e. all transceivers can be connected to all antennas, e.g. by a combined digital feed RF chip) and the controller  806  may flexibly optimize which antenna  807 ,  808 ,  809  is chosen for which connection. For example, one antenna may be degraded by shadowing for the cellular connection while due to the different angle of reception another antenna may be degraded for the tethering connection. The controller  806  may assign antennas taking such effects into account. 
     While specific aspects have been described, it should be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the aspects of this disclosure as defined by the appended claims. The scope is thus indicated by the appended claims and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced.

Metadata:
Filing Date: 20160425
Publication Date: 20210511
Grant Date: 20210511
Priority Date: 20130524
Inventors: CLEVORN, THORSTEN
HERRERO, PABLO
PERLMUTTER, URI
KRONFELD, RONEN
Assignee: APPLE INC
CPC Classifications: [{"code": "H04W72/542", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0689", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B7/0689", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0877", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0693", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0871", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0871", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W88/06", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W72/046", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0693", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0877", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0693", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0486", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B7/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0877", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0871", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0689", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04L5/0023", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W88/06", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04B7/0486", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W72/046", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0689", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0877", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L5/0023", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0693", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0871", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W72/085", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/04", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 51863308