Radio communication apparatus

Abstract

A radio communication apparatus is provided which comprises first and second radio circuit portions arranged to receive radio signals in a common frequency band from an antenna, the first and second radio circuit portions comprising respective first and second amplifiers. An amplifier sharing portion is operable to direct radio signals amplified by the first amplifier to one or more further components of the second radio circuit portion. The radio communication apparatus is operable in a first mode in which only the first radio circuit portion is configured to receive radio signals, said radio signals being amplified using the first amplifier, a second mode in which only the second radio circuit portion is configured to receive radio signals, said radio signals being amplified using the second amplifier, and a third mode in which the first and second radio circuit portions are configured to receive radio signals, said radio signals being amplified by the first amplifier and directed to one or more further components of the second radio circuit portion using the amplifier sharing portion.

Description

[0001] Radio Communication Apparatus

[0002] BACKGROUND OF THE INVENTION

[0003] The present invention relates to a radio communication apparatus.

[0004] Many different wireless radio communication protocols share the same or overlapping frequency bands. For instance, Bluetooth, Zigbee, Thread and some wireless local-area network (WLAN) protocols use the 2.4 GHz industrial, scientific, and medical (ISM) band, because in many countries it can be used at low powers without a specific licence. This can lead to communication issues when signals according to such protocols are transmitted or received simultaneously in close proximity. When two or more radio communication protocols operate in close proximity and share the same frequency band, they are sometimes referred to as coexisting protocols.

[0005] Many modern devices can themselves support multiple wireless communication protocols that share the same frequency band - e.g. a modern mobile telephone may support a Bluetooth connection (e.g. with wireless headphones) at the same time as a WLAN connection (e.g. with a Wi-Fi router). Some devices are even arranged to use a common antenna for protocols sharing the same frequency band, to reduce part count. To avoid interference issues, devices supporting multiple wireless communication protocols that share the same frequency band typically implement coexistence procedures. Conventional coexistence procedures include packet traffic arbitration (PTA), in which different radio modules send communication request signals (i.e. requests to send or receive a data packet in a particular time window) to an arbitration circuit, which issues a grant signal to only one radio module at a time. This avoids conflicts between the two radio modules, reducing packet losses.

[0006] However, conventional approaches to coexistence may not result in optimal behaviour for all communication situations. An improved approach may be desired. SUMMARY OF THE INVENTION

[0007] According to a first aspect of the present invention there is provided a radio communication apparatus comprising: a first radio circuit portion arranged to receive radio signals in a common frequency band from an antenna, the first radio circuit portion comprising a first amplifier and one or more further components for processing radio signals; a second radio circuit portion arranged to receive radio signals in the common frequency band from the antenna, the second radio circuit portion comprising a second amplifier and one or more further components for processing radio signals; and an amplifier sharing portion operable to direct radio signals amplified by the first amplifier to the one or more further components of the second radio circuit portion; wherein the radio communication apparatus is operable in: a first mode in which only the first radio circuit portion is configured to receive radio signals, said radio signals being amplified using the first amplifier; a second mode in which only the second radio circuit portion is configured to receive radio signals, said radio signals being amplified using the second amplifier; and a third mode in which the first and second radio circuit portions are configured to receive radio signals, said radio signals being amplified by the first amplifier and directed to the one or more further components of the second radio circuit portion using the amplifier sharing portion.

[0008] Thus, as will be appreciated by those skilled in the art, the amplifier sharing portion enables the second radio circuit portion to make use of the first amplifier in the third mode, allowing the radio communication apparatus to be operated more efficiently and / or with greater sensitivity compared to each radio circuit portion using its own amplifier in all circumstances (e.g., with radio signals from the antenna being split between the first and second radio circuit portions before amplification). Whilst the first amplifier may not always be optimised for use with the further components of the second radio circuit portion, the inventors have recognised that this may be acceptable in many situations in exchange for the improvements in efficiency and / or sensitivity. The amplifier sharing portion may be arranged, in the third mode, to direct radio signals amplified by the first amplifier to a node in the second radio circuit portion to which the second amplifier outputs amplified radio signals in the second mode. In other words, the amplifier sharing portion may allow the first amplifier to be used as a direct replacement of the second amplifier in the third mode. This may enable smoother switching in and out of the third mode (e.g. with minimal or no interruptions). In a set of embodiments, the first amplifier may comprise a buffer via which amplified radio signals are directed to the one or more further components of the second radio circuit portion in the third mode.

[0009] The radio communication apparatus may operate in the first mode when only the first radio circuit portion is expecting to receive radio signals, or when the first radio circuit portion’s reception of radio signals is prioritised. For instance, the radio communication apparatus may operate in the first mode at a time when the first radio circuit portion is scheduled to receive radio signals, or when a radio signal for the first radio circuit portion is detected (e.g. when processing of incoming radio signals indicates the presence of data for the first radio circuit portion).

[0010] Similarly, the radio communication apparatus may operate in the second mode when only the second radio circuit portion is expecting to receive radio signals, or when the second radio circuit portion’s reception of radio signals is prioritised.

[0011] The radio communication apparatus may operate in the third mode when both of the first and second radio circuit portions are expecting to receive radio signals, or equally when neither of the first and second radio circuit portions are expecting to receive radio signals. In other words, the radio communication apparatus may operate in the third mode to allow both of the first and second radio circuit portion to listen for incoming radio signals.

[0012] The fact that both radio circuit portions are enabled in the third mode may increase power usage in this mode compared to the first and second modes (although the sharing of the amplifier may mitigate this to a degree). The radio communication apparatus may therefore be arranged to switch from the third mode into one of the first and second modes if radio signals received in the third mode indicate an imminent period in which only radio signals for the first or second radio circuit portion will arrive, or an imminent period in which reception by the first or second radio circuit portion should be prioritised. In other words, the radio communication apparatus may operate in the third mode to allow both radio circuit portions to listen for incoming radio signals, and then switch to the first or second mode as appropriate to reduce power use.

[0013] The inventors have recognised, however, that switching between the first, second and third modes may briefly disrupt the reception of radio signals. In a set of embodiments, therefore, the radio communication apparatus is arranged to inhibit switching from the third mode to the first or second mode whilst the first or second radio circuit portion is actively receiving radio signals (e.g. decoding information from received radio signals) in the third mode. For instance, the radio communication apparatus may block mode switching until the first or second radio circuit portion has finished receiving a data packet. This may help to mitigate reception errors. Additionally or alternatively, in a set of embodiments, the radio communication apparatus is arranged to inhibit switching from the first or second mode to the third mode whilst the first or second radio circuit portion is actively receiving radio signals.

[0014] The amplifier sharing portion may simply comprise a permanent electrical connection between suitable nodes in the first and second radio circuit portions. However, in some embodiments, when not in the third mode (e.g. when in the first and second modes), the amplifier sharing portion may disconnect the first amplifier from the second radio circuit portion. This may avoid unnecessarily loading either radio circuit portion when the first amplifier is not being shared.

[0015] In a set of embodiments, the amplifier sharing portion comprises a switch operable to connect and disconnect the first amplifier from the second radio circuit portion. In some such embodiments, the amplifier sharing portion comprises a first switch and a second switch, and both switches operate to connect and disconnect the first amplifier from the second radio circuit portion. A conduction path from the first switch to the first radio circuit portion may have a lower impedance than a conduction path between the first switch and the second radio circuit portion. Similarly, a conduction path from the second switch to the second radio circuit portion may have a lower impedance than a conduction path between the second switch and the first radio circuit portion. Having the first and second switches “near” to their respective radio circuit portions in this way may minimise loading of both radio circuit portions when the radio communication apparatus is not in the third mode, i.e. by allowing superfluous conduction paths to be entirely disconnected when they are not in use. This may also mitigate inadvertent picking up of noise or other interference.

[0016] The first switch may be provided with the first radio circuit portion (e.g. on the same PCB or in the same chip). Similarly, the second switch may be provided with the second radio circuit portion (e.g. on the same PCB or in the same chip). It will be understood that references to “switches” extend to appropriately configured semiconductor-based equivalents such as field-effect and other transistors.

[0017] In some embodiments one or both of the first and / or second radio circuit portions may be arranged to only receive radio signals (i.e. they may be radio receivers only). However, in a set of embodiments, the first radio circuit portion is also arranged to transmit radio signals in the common frequency band. Additionally or alternatively, the second radio circuit portion may be arranged to transmit radio signals in the common frequency band. In other words, the first and / or second radio circuit portion may comprise a radio transceiver, i.e. arranged to transmit and receive radio signals. The first and / or second radio circuit portions may comprise various radio transmission components for transmitting radio signals in the common frequency band (e.g. one or more amplifiers, mixers, baluns or filters).

[0018] Because the first and second radio circuit portion both operate using radio signals in the common frequency band, there is the possibility of interference between communications to (or from) the first and second radio circuit portions causing errors and / or lost data. Therefore, in a set of embodiments, the radio communication apparatus comprises an arbitration circuit portion arranged to coordinate access to the common frequency band by the first and second radio circuit portions.

[0019] The first and / or second radio circuit portions may be arranged to send communication request signals to the arbitration circuit portion (e.g. to request access to the common frequency band to receive radio signals). The arbitration circuit portion may be arranged to issue grant and / or refusal signals in response to communication request signals. In other words, the arbitration circuit portion may be arranged to grant or refuse communication requests from the first and / or second radio circuit portions. The arbitration circuit portion may determine an arbitration outcome (e.g. grant or refusal) based on an input state determined from the communication request signals. The arbitration outcome may be determined based on fixed arbitration rules and / or based on a look-up table of input states and arbitration outcomes. The arbitration circuit portion may comprise a packet traffic arbiter (PTA).

[0020] A communication request signal may comprise a transmit request, a receive request, or another radio operation request (e.g. a combined request for transmission, or reception if transmission is not possible). A communication request signal may comprise supplementary information, e.g. indicating a communication type of a communication request (e.g. a transmission or a reception), and / or indicating a priority of the communication request (e.g. whether the communication requested is of high priority or low priority), and / or indicating a current activity of the first or second radio circuit portion (i.e. a current state of the first or second radio circuit portion).

[0021] In some embodiments, the arbitration circuit portion may be arranged to receive communication request signals from only one of the first and second radio circuit portions. In other words, one of the first and second radio circuit portions may not itself be able to request permission to use the common frequency band. For instance, one of the first and second radio circuit portions may simply be unilaterally allocated use of the common frequency band at suitable times. However, the arbitration circuit portion may be arranged to receive communication request signals from the first radio circuit portion and the second radio circuit portion.

[0022] The radio communication apparatus may comprise a communication channel between the arbitration circuit portion and first and / or second radio circuit portions. The arbitration circuit portion may comprise one or more interfaces for sending and / or receiving signals from the first and / or second radio circuit portions. The arbitration circuit portion may be connected to the first radio circuit portion and / or the second radio circuit portion by a 1-wire connection (e.g. a single conductor). The 1-wire connection may provide a single communication channel for sending a grant signal to the first or second radio circuit portion. In some embodiments, the arbitration circuit portion is arranged to be connected to the first radio circuit portion and / or the second radio circuit portion by a 2-wire connection, e.g., facilitating the reception of request signals and the issuing of grant signals. In some embodiments, the arbitration circuit portion is arranged to be connected to the first radio circuit portion and / or the second radio circuit portion by a 3- or 4-wire connection, e.g., facilitating the reception of request signals, the issuing of grant signals and the reception of supplementary information. More complex communication channels (e.g. with more wires) may also be used. In some embodiments, the radio communication apparatus may comprise one or more data buses for communication between the arbitration circuit portion and the first and / or second radio circuit portions.

[0023] The first and second radio circuit portions share the same antenna, which can help to reduce the part count, cost and size of the radio communication apparatus. The use of the antenna may need to be carefully managed to avoid conflicts or even damage. In a set of embodiments, the radio communication apparatus comprises an antenna switching portion for selectively connecting the antenna to either the first radio circuit portion or the second radio circuit portion. In some such embodiments, the antenna cannot be connected to both radio circuit portions at the same time, e.g., to mitigate a situation in which one radio circuit portion transmits high power radio signals into the other radio circuit portion. The antenna may be part of the radio communication apparatus or it may be provided separately. Similarly, the antenna switching portion may be provided separately, with the radio communication apparatus simply being arranged to control the antenna switching portion appropriately.

[0024] The antenna switching portion may be arranged to connect the antenna to the first radio circuit portion in the first and third modes, and to connect the antenna to the second radio circuit portion in the second mode. In other words, the antenna switching portion may connect the antenna to the first radio circuit portion when only the first radio circuit portion is receiving radio signals or when the first and second radio circuit portions are receiving radio signals, and connect the antenna to the second radio circuit portion when only the second radio circuit portion is receiving radio signals.

[0025] The antenna switching portion may be used for transmissions too, in relevant embodiments. The antenna switching portion may connect the antenna to (only) the first radio circuit portion when the first radio circuit portion is transmitting radio signals and connect the antenna to (only) the second radio circuit portion when the second radio circuit portion is transmitting radio signals.

[0026] The antenna switching portion may comprise one or more switches (or semiconductor-based equivalents), e.g. a single-pole-multiple-throw switch.

[0027] The antenna switching portion may be controlled directly by the first and / or second radio circuit portions and / or by an arbitration circuit portion, e.g. to configure the antenna switching portion appropriately for one or more communication requests that have just been granted.

[0028] However, in a set of embodiments the radio communication apparatus comprises an antenna switching controller arranged to control an antenna switching portion (e.g. to control a state of one or more switches of the antenna switching portion). The antenna switching controller may be configured to determine an appropriate setting for the antenna switching portion based on one or more inputs from the first and / or second radio circuit portions and / or an arbitration circuit portion (e.g. said inputs indicating one or more communication requests that have just been granted, or one or more active or imminent communications). In a set of embodiments, the first and / or second radio circuit portion is configured to indicate its communication state (e.g. transmitting, receiving, idle) to the antenna switching controller and the antenna switching controller is arranged to control the antenna switching portion in response. Additionally or alternatively, the first and / or second radio circuit portion may be configured to indicate a communication intent (e.g. to transmit, receive, neither) to the antenna switching controller (i.e. an indication of a future state) and the antenna switching controller may be arranged to control the antenna switching portion in response. The antenna switching controller may operate according to fairly simple rules. In some embodiments, the antenna switching controller may be provided primarily or entirely in hardware, i.e. the operation of the antenna switching controller may not rely on control software being executed by an associated processor. This may improve efficiency and / or speed and / or robustness (e.g. by mitigating the risk of software bugs arising through updates of control software causing errors).

[0029] In a set of embodiments, the antenna switching portion and / or an antenna switching controller is arranged to provide feedback to the first and / or second radio circuit portion on a connection setting of the antenna (e.g. to indicate which radio circuit portion the antenna is currently connected to). In embodiments where one or both of the first and second radio circuit portions is operable to transmit radio signals, said first and / or second radio circuit portion may be arranged only to transmit when the feedback indicates that it is connected to the antenna. In other words, the antenna switching portion and / or the antenna switching controller may be arranged to block a radio circuit portion from transmitting when the antenna is not connected to said radio circuit portion. This may mitigate the risk of damage caused by an active transmitter being disconnected from its energy sink (the antenna).

[0030] The amplifier sharing portion may be controlled directly by the first and / or second radio circuit portions and / or by an arbitration circuit portion, e.g. to configure the amplifier sharing portion appropriately for one or more communication requests that have just been granted. In other words, the first and / or second radio circuit portions and / or an arbitration circuit portion may cause the radio communication apparatus to operate in a suitable mode for current and / or upcoming communications. For instance, if the arbitration circuit portion has just granted two concurrent receive requests by the first and second radio circuit portions, it may accordingly control the amplifier sharing portion such that the radio communication apparatus operates in the third mode.

[0031] However, in a set of embodiments the radio communication apparatus comprises an amplifier sharing controller arranged to control the amplifier sharing portion (e.g. to control a state of one or more switches). The amplifier sharing controller may be configured to determine an appropriate setting for the amplifier sharing portion based on one or more inputs from the first and / or second radio circuit portions and / or an arbitration circuit portion (e.g. said inputs indicating one or more communication requests that have just been granted, or one or more active or imminent communications). In a set of embodiments, the first and / or second radio circuit portion is configured to indicate its communication state or intent (e.g. transmitting, receiving, idle) to the amplifier sharing controller and the amplifier sharing controller is arranged to control the amplifier sharing portion accordingly. In such embodiments it will be recognised that the amplifier sharing controller controls the radio communication apparatus to operate in the first, second or third mode as appropriate.

[0032] For instance, the input(s) from the first and / or second radio circuit portions and / or an arbitration circuit portion may indicate that the only the first or only the second radio circuit portion is in or is entering a radio reception state, and the amplifier sharing controller may accordingly cause the radio circuit portion to operate in the first or second state respectively. Alternatively, the input(s) may indicate that the first and the second radio circuit portions are entering a radio reception state, and the amplifier sharing controller may accordingly cause the radio circuit portion to operate in the third state.

[0033] The amplifier sharing controller may be provided primarily or entirely in hardware, i.e. the operation of the amplifier sharing controller may not rely on control software being executed by an associated processor. This may improve efficiency and / or speed and / or robustness.

[0034] The operations of the amplifier sharing portions and antenna switching portions are closely related. In embodiments with a switchable antenna, successful operation in the first, second and third modes may rely on an appropriate configuration of the antenna switching portion. In a set of embodiments, therefore, the antenna switching controller is also configured to perform the functions of the amplifier sharing controller (i.e. the antenna switching controller may comprise the amplifier sharing controller). In such embodiments, the antenna switching controller may be arranged to control the amplifier sharing portion and the antenna switching portion in response to a single set of one or more inputs from the first and / or second radio circuit portions and / or an arbitration circuit portion. This may simplify circuitry and help to optimise performance. It will be appreciated that the antenna switching controller and / or the amplifier sharing controller may operate in concert with an arbitration circuit portion to achieve proper operation of the radio communication apparatus. For instance, the first and / or second radio circuit portion may first request permission for a given communication from the arbitration circuit portion (e.g. by sending one or more relevant communication request signals), and if permission is granted (e.g. if the arbitration circuit portion replies with a grant signal), instruct the antenna switching controller and / or the amplifier sharing controller as appropriate to obtain the necessary configuration of the amplifier sharing portion and / or the antenna switching portion. This process may repeat for further communications, with the arbitration circuit portion deciding which communications can occur and the antenna switching controller and / or the amplifier sharing controller implementing the necessary changes to the amplifier sharing portion and / or the antenna switching portion to perform said communications. In some embodiments, the arbitration circuit portion may be integrated with the amplifier sharing controller and / or the antenna switching controller (e.g. provided by a single circuit portion). In other words, the arbitration circuit portion may be configured to perform the functions of the amplifier sharing controller and / or the antenna switching controller.

[0035] In a set of embodiments, the first radio circuit portion is arranged to receive (and optionally transmit) radio signals according to a first wireless communication protocol (i.e. data may be encoded in the radio signals according to the first wireless communication protocol and / or the radio signals themselves may follow timing and / or modulation rules according to the first wireless communication protocol). The first wireless communication protocol may be a wireless local area network (WLAN) protocol, e.g., according to one of the IEEE 802.11 standards, often referred to as Wi-Fi. In some embodiments, the second radio circuit portion is arranged to receive (and optionally transmit) radio signals according to a second wireless communication protocol, different to said first wireless communication protocol (i.e. data may be encoded in the radio signals according to the second wireless communication protocol and / or the radio signals themselves may follow timing and / or modulation rules according to the second wireless communication protocol). The second wireless communication protocol may be a wireless personal area network (WPAN) protocol e.g. according to one of the IEEE 802.15 standards. For instance, the second wireless communication protocol may be Bluetooth, Zigbee or Thread (e.g. Bluetooth Low Energy (LE)). The first wireless communication protocol may support longer-range and / or higher data rate communications than the second wireless communication protocol.

[0036] Conversely, the second wireless communication protocol may support longer-range and / or higher data rate communications than the first wireless communication protocol. The second wireless communication protocol may be a wireless local area network (WLAN) protocol, and / or the first wireless communication protocol may be a wireless personal area network (WPAN) protocol.

[0037] The common frequency band may be an industrial, scientific and medical (ISM) radio band. For instance, the common frequency band may include frequencies between 2.4 GHz - 2.5 GHz.

[0038] The first and / or second radio circuit portion may not be limited to communicating in only the common frequency band. In a set of embodiments the first and / or second radio circuit portion is arranged to send and / or receive radio signals in a second frequency band. For instance, the first and / or second radio circuit portion may be operable to communicate using a 5 GHz IEEE 802.11 communication protocol in addition to a 2.4 GHz IEEE 802.11 communication protocol. The radio circuit portion may be able to communicate in further frequency bands (third, fourth, etc.).

[0039] The first and second amplifiers apply a gain to incoming radio signals, e.g. to allow said signals to be processed efficiently by the one or more further components. In practice, the strength of radio signals received by the first and second radio circuit portions will vary, dependent on numerous factors such as the distance to and power output of a transmitter, the frequency at which the signals are transmitted and the environmental surroundings. However, it is often desirable to keep the amplitude of amplified signals within a certain range, e.g. to allow for optimal use of elements in a signal reception chain such as an analogue-to-digital converter. Many radio communication devices thus actively control a gain applied to incoming radio signals to optimise performance, referred to as automatic gain control (AGO). In a set of embodiments, the first amplifier has a controllable gain. The first radio circuit portion may be arranged to control a gain applied by the first amplifier based on a strength of the received radio signals. Similarly, the second amplifier may have a controllable gain and the second radio circuit portion may be arranged to control said gain. Gain control may be operated using one or more feedback loops, e.g. by measuring a strength of radio signals after they have been amplified.

[0040] However, the applicant has recognised that, in the third mode when both the first and second radio circuit portions receive radio signals amplified by the first amplifier, active gain control by the first radio circuit portion may cause errors in the reception of the radio signals by the second radio circuit portion. For instance, significant changes to the gain applied by the first amplifier (e.g. to aid reception of data encoded in the radio signals according to a first wireless communication protocol) may prevent the second radio circuit portion from effectively retrieving data encoded in the amplified radio signals according to the second wireless communication protocol. Thus, in a set of embodiments, the first radio circuit portion is arranged to follow a gain control limitation when the radio communication apparatus operates in the third mode. The gain control limitation may comprise preventing any changes to the gain during third mode operation, or it may comprise reducing an allowable gain range and / or rate of gain change during third mode operation.

[0041] In a set of embodiments, the first and second radio circuit portions are arranged to communicate gain information. For instance, the first radio circuit portion may be arranged to indicate to the second radio circuit portion a gain applied by the first amplifier, e.g., to allow the second radio circuit portion to determine accurately a Received Signal Strength Indicator (RSSI) in the third mode.

[0042] The first and / or second radio circuit portions may be used for packet-based radio communications in which data is encoded into radio signals in distinct blocks. When the first and / or second radio circuit portions are configured to receive radio signals they may be scanning for incoming packets and / or processing incoming packets.

[0043] The first radio circuit portion may comprise an analogue front-end portion comprising the first amplifier and at least one of the one or more further components. The first amplifier may be a low noise amplifier (LNA). The one or more further components may comprise one or more filters, mixers, baluns, additional amplifiers or analogue-to-digital converters (ADCs). Similarly, the second radio circuit portion may comprise an analogue front-end portion comprising the second amplifier and at least one of the one or more further components (e.g. one or more filters, mixers, baluns, additional amplifiers or analogue-to-digital converters (ADCs)). The second amplifier may be a low noise amplifier (LNA). Additionally or alternatively, the first and / or second radio circuit portions may comprise a digital baseband portion comprising at least one of the one or more further components (e.g. a baseband processor). The first and / or second radio circuit portion may comprise in-phase and quadrature signal paths for incoming and / or outgoing radio signals (i.e. comprising l / Q pairs of one or more components in the reception or transition signal paths).

[0044] The first and / or second radio circuit portions may comprise a microcontroller, e.g. for controlling an analogue front-end portion, a digital baseband portion and / or for communicating with other parts of the radio communication apparatus. For instance, the microcontroller may be responsible for sending communication request signals to an arbitration circuit portion and / or receiving grant and / or refusal signals from an arbitration circuit portion.

[0045] The radio communication apparatus described herein has first and second radio circuit portions which use a common frequency band for communications (i.e. first and second coexisting radio circuit portions). However, the radio communication apparatus is not limited to only two radio circuit portions. In a set of embodiments, the radio communication apparatus comprises one or more additional radio circuit portion arranged to transmit and / or receive signals. The one or more additional radio circuit portions may also be arranged to communicate (i.e. transmit and / or receive radio signals) in the common frequency band, although in some embodiments the radio communication apparatus comprises one or more additional radio circuit portions arranged to communicate in a different frequency band (e.g. a 5 GHz WLAN radio alongside co-existing Bluetooth LE and 2.4 GHz WLAN radios).

[0046] The radio communication apparatus may comprise an integrated circuit such as a System-on-Chip (SoC). The radio communication apparatus may comprise a single physical device, e.g. a single SoC. Alternatively, the radio communication apparatus may comprise several physical devices (e.g. several integrated circuits (ICs)) connected together.

[0047] The radio communication apparatus may comprise a primary circuit portion (e.g. an application processor) which receives data from received radio signals from the first and second radio circuit portions. In relevant embodiments, the primary circuit portion may be arranged to send data to be transmitted to the first and / or second radio circuit portions.

[0048] The primary circuit portion may be provided separately to the radio communication apparatus (e.g. as a separate SoC). For instance, the present invention extends to a radio communication device comprising a primary circuit portion and the radio communication apparatus disclosed herein, wherein the primary circuit portion uses the radio communication apparatus to receive (and optionally send) data encoded in radio signals. For instance, the primary circuit portion may comprise an application processor.

[0049] Features of any aspect or embodiment described herein may, wherever appropriate, be applied to any other aspect or embodiment described herein. Where reference is made to different embodiments, it should be understood that these are not necessarily distinct but may overlap.

[0050] BRIEF DESCRIPTION OF THE DRAWINGS

[0051] One or more non-limiting examples will now be described, by way of example only, and with reference to the accompanying figures in which:

[0052] Figure 1 is a schematic view of a radio communication device according to an embodiment of the invention; and

[0053] Figure 2 is a more detailed schematic view of part of the radio communication device of Figure 1.

[0054] DETAILED DESCRIPTION

[0055] A radio communication device 100 is shown in Figure 1. The device 100 comprises an application processor 102, an RF System-on-Chip (SoC) 104, an antenna switching portion 106 and a shared antenna 108. The SoC 104 comprises a WLAN radio module 110, a WPAN (e.g. Bluetooth Low Energy (BLE)) radio module 112, an arbitration circuit portion 114, an antenna switching controller 115 and an amplifier sharing portion 117. In another example not shown, the application processor 102 may be part of the SoC 104.

[0056] The WLAN radio module 110 comprises a WLAN microcontroller 116 and a WLAN RF portion 118. The WLAN microcontroller 116 controls the WLAN RF portion 118 to send and receive radio packets using a 2.4 GHz frequency band and a 5 GHz frequency band. The WPAN radio module 112 comprises a WPAN microcontroller 120 and a WPAN RF portion 122. The WPAN microcontroller 120 controls the RF portion 122 to send and receive radio packets using the 2.4 GHz frequency band. The application processor 102 communicates with the WLAN and WPAN microcontrollers 116, 120, to control their operation and to send and receive data.

[0057] In use, the application processor 102 uses the SoC 104 to send and receive data encoded in radio signals, with the WLAN radio module 110 being used to send and receive WLAN radio packets and the WPAN radio module 112 being used to send and receive WPAN radio packets.

[0058] The WLAN radio module 110 and the WPAN radio module 112 share the same antenna 108. The antenna switching portion 106 connects the antenna 108 to only one of the WLAN radio module 110 and the WPAN radio module 112 at a given time under the control of the antenna switching controller 115. The antenna switching portion 106 is shown in Figures 1 and 2 as connecting only the WLAN radio module 110 to the antenna 108. As will be explained below in more detail, the amplifier sharing portion 117 is operable to connect an amplifier of the WLAN radio module 110 to the WPAN radio module 112, under the control of the antenna switching controller 115.

[0059] Because the WLAN radio module 110 and the WPAN radio module 112 share the same antenna 108 and the same 2.4 GHz frequency band, the arbitration circuit portion 114 coordinates access to this frequency band to avoid conflicts using a request / grant protocol. When one of the radio modules 110, 112 wishes to access the common 2.4 GHz frequency band (i.e. to send or receive radio signals), its microcontroller 116, 120 sends a communication request signal (labelled R in Figure 1) to the arbitration circuit portion 114. If the requested communication would not result in any unacceptable conflicts, the arbitration circuit portion 114 grants the request by issuing a grant signal (labelled G). If the request is refused, no grant signal is issued.

[0060] Once a communication request has been granted, the relevant microcontroller 116, 120 controls its RF portion 118, 122 to perform the necessary transmission or reception. To allow the appropriate transmission or reception to take place, the antenna switching portion 106 and the amplifier sharing portion 117 must be configured appropriately. The RF portions 118, 122 indicate to the antenna switching controller 115when they are transmitting (signal TX) or receiving (signal RX), so that the antenna switching controller 115can configure the antenna switching portion 106 and the amplifier sharing portion 117 appropriately.

[0061] Figure 2 shows part of the radio communication device 100 in more detail. The WLAN RF portion 118 comprises an analogue front-end portion 119, and the WPAN RF portion 122 comprises an analogue front-end portion 123. The WLAN RF front-end portion 119 comprises a transmit path 121 for transmitting radio signals and a receive path 124 for receiving radio signals. The receive path 124 comprises a low-noise amplifier (LNA) 126, a mixer 128 and a filter 130. The transmit path 121 comprises corresponding components.

[0062] Similarly, the WPAN RF front-end portion 123 comprises a transmit path 132 for transmitting radio signals and a receive path 134 for receiving radio signals. The receive path 134 comprises an LNA 136, a mixer 138 and a filter 140. The transmit path 132 comprises corresponding components.

[0063] The amplifier sharing portion 117 connects the output of the WLAN reception amplifier 126 to the input of the WPAN reception mixer 138 via first and second switches 117A, 117B. The first switch 117A is located physically near to the WLAN analogue front-end portion 119, and the second switch 117B is located physically near to the WPAN analogue front-end portion 123. To connect the output of the WLAN reception amplifier 126 to the input of the WPAN reception mixer 138, both switches 117A, 117B are closed. To disconnect the output of the WLAN reception amplifier 126 from the input of the WPAN reception mixer 138, both switches 117A, 117B are opened. Using two switches located near to the connection nodes minimises additional load on the front-end portions 119, 123 and mitigates the picking up of noise or other interference when the switches 117A, 117B are open.

[0064] The operation of the radio communication device 100 for receiving radio signals will now be explained in more detail. In particular, the operation of the radio communication device 100 will be described in the situation where both the WLAN radio module 110 and the WPAN radio module 112 seek to operate using the common 2.4 GHz frequency band.

[0065] As the radio communication device 100 is used, the application processor 102 may wish to use the SoC 104 to scan for incoming WLAN packets or incoming WPAN packets.

[0066] To scan for WLAN packets, the application processor 102 instructs only the WLAN microcontroller 116 to enter a scanning mode. The WLAN microcontroller 116 accordingly sends a receive communication request to the arbitration circuit portion 114. No other communication is ongoing, so the arbitration circuit portion 114 grants the request.

[0067] On receipt of the grant signal, the WLAN microcontroller 116 controls the WLAN RF portion 118 to start to receive radio signals and scan them for incoming WLAN packets. The RF portion 118 indicates to the antenna switching controller 115that it is about to start receiving radio signals. In response, the antenna switching controller 115controls the antenna switching portion 106 to connect the antenna 108 to the WLAN RF front-end portion 119, and controls the amplifier sharing portion 117 to disconnect the output of the WLAN reception amplifier 126 from the input of the WPAN reception mixer 138.

[0068] Radio signals picked up by the antenna 108 are directed to the WLAN reception amplifier 126, amplified and sent on to the other components of the WLAN RF portion 118 for processing. This is the SoC 104 operating in a first reception mode.

[0069] To scan for only WPAN packets, a similar process happens but with the WPAN radio module 112. The antenna switching controller 115controls the antenna switching portion 106 to connect the antenna 108 to the WPAN RF front-end portion 123, and controls the amplifier sharing portion 117 to disconnect the output of the WLAN reception amplifier 126 from the input of the WPAN reception mixer 138. Radio signals picked up by the antenna 108 are directed to the WPAN reception amplifier 136, amplified and sent on to the other components of the WPAN RF portion 123 for processing. This is the SoC 104 operating in a second reception mode.

[0070] In some situations, the application processor 102 may wish to use the SoC 104 to scan for incoming WLAN packets and incoming WPAN packets at the same time. In such situations, the application processor 102 instructs both the WLAN and WPAN microcontrollers 116, 120 to enter the scanning mode. Both microcontrollers 116, 120 send receive communication requests to the arbitration circuit portion 114. The arbitration circuit portion 114 is configured to permit concurrent reception and so both requests are granted.

[0071] Accordingly, both RF portions 118, 122 indicate to the antenna switching controller 115that they are about to start receiving radio signals. The antenna switching controller 115controls the antenna switching portion 106 to connect the antenna 108 to the WLAN RF front-end portion 119, and controls the amplifier sharing portion 117 to connect the output of the WLAN reception amplifier 126 to the input of the WPAN reception mixer 138.

[0072] In this configuration the WPAN RF front-end portion 123 utilises the WLAN reception amplifier 126 instead of its own amplifier 136. Radio signals picked up by the antenna 108 are directed to the WLAN reception amplifier 126, amplified and sent on to the other components of the WLAN RF portion 118 and the other components of the WPAN RF portion for processing. This is the SoC 104 operating in a third reception mode. Figure 2 shows the SoC 104 configured to operate in this third reception mode.

[0073] Concurrent reception could be achieved by simply splitting signals from the antenna 108 between the WLAN and WPAN radio modules 110, 112. However, the WPAN radio module 112 making use of the WLAN reception amplifier 126 in the third reception mode, embodiments of the present invention can enable concurrent reception more efficiently and / or with greater sensitivity, because the radio signals are not split before amplification.

[0074] While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.

Claims

Claims1. A radio communication apparatus comprising: a first radio circuit portion arranged to receive radio signals in a common frequency band from an antenna, the first radio circuit portion comprising a first amplifier and one or more further components for processing radio signals; a second radio circuit portion arranged to receive radio signals in the common frequency band from the antenna, the second radio circuit portion comprising a second amplifier and one or more further components for processing radio signals; and an amplifier sharing portion operable to direct radio signals amplified by the first amplifier to the one or more further components of the second radio circuit portion; wherein the radio communication apparatus is operable in: a first mode in which only the first radio circuit portion is configured to receive radio signals, said radio signals being amplified using the first amplifier; a second mode in which only the second radio circuit portion is configured to receive radio signals, said radio signals being amplified using the second amplifier; and a third mode in which the first and second radio circuit portions are configured to receive radio signals, said radio signals being amplified by the first amplifier and directed to the one or more further components of the second radio circuit portion using the amplifier sharing portion.

2. The radio communication apparatus of claim 1 , wherein the amplifier sharing portion is arranged, in the third mode, to direct radio signals amplified by the first amplifier to a node in the second radio circuit portion to which the second amplifier outputs amplified radio signals in the second mode.

3. The radio communication apparatus of claim 1 or 2, wherein the first amplifier comprises a buffer via which amplified radio signals are directed to the one or more further components of the second radio circuit portion in the third mode.

4. The radio communication apparatus of any preceding claim, wherein the amplifier sharing portion disconnects the first amplifier from the second radio circuit portion when the radio communication apparatus is not in the third mode.

5. The radio communication apparatus of any preceding claim, wherein the amplifier sharing portion comprises a first switch and a second switch, and both switches operate to connect and disconnect the first amplifier from the second radio circuit portion; and wherein a conduction path from the first switch to the first radio circuit portion has a lower impedance than a conduction path between the first switch and the second radio circuit portion, and a conduction path from the second switch to the second radio circuit portion has a lower impedance than a conduction path between the second switch and the first radio circuit portion.

6. The radio communication apparatus of any preceding claim, arranged to inhibit switching from the third mode to the first or second mode whilst the first or second radio circuit portion is actively receiving radio signals in the third mode.

7. The radio communication apparatus of any preceding claim, arranged to inhibit switching from the first or second mode to the third mode whilst the first or second radio circuit portion is actively receiving radio signals.

8. The radio communication apparatus of any preceding claim, wherein the first and / or second radio circuit portion comprises a radio transceiver.

9. The radio communication apparatus of any preceding claim, comprising an arbitration circuit portion arranged to coordinate access to the common frequency band by the first and second radio circuit portions.

10. The radio communication apparatus of any preceding claim, comprising an antenna switching portion for selectively connecting the antenna to either the first radio circuit portion or the second radio circuit portion, wherein the antenna switching portion is arranged to connect the antenna to the first radio circuit portion in the first and third modes, and to connect the antenna to the second radio circuit portion in the second mode.

11. The radio communication apparatus of any preceding claim, comprising an antenna switching controller arranged to control the antenna switching portion, wherein the first and / or second radio circuit portion is configured to indicate its communication state or communication intent to the antenna switching controller and the antenna switching controller is arranged to control the antenna switching portion in response.

12. The radio communication apparatus of any preceding claim, comprising an amplifier sharing controller arranged to control the amplifier sharing portion, wherein the amplifier sharing controller is configured to determine an appropriate setting for the amplifier sharing portion based on one or more inputs from the first and / or second radio circuit portions.

13. The radio communication apparatus of any preceding claim, wherein the first radio circuit portion is arranged to receive radio signals according to a first wireless communication protocol and the second radio circuit portion is arranged to receive radio signals according to a second wireless communication protocol.

14. The radio communication apparatus of claim 13, wherein the first wireless communication protocol is a wireless local area network protocol and the second wireless communication protocol is a wireless personal area network protocol.

15. The radio communication apparatus of any preceding claim, wherein the common frequency band is an industrial, scientific and medical radio band.

16. The radio communication apparatus of any preceding claim, wherein the first amplifier has a controllable gain and the first radio circuit portion is arranged to control a gain applied by the first amplifier based on a strength of the received radio signals, wherein the first radio circuit portion is arranged to follow a gain control limitation when the radio communication apparatus operates in the third mode17. The radio communication apparatus of any preceding claim, wherein the first radio circuit portion is arranged to indicate to the second radio circuit portion a gain applied by the first amplifier.

18. The radio communication apparatus of any preceding claim, wherein the first amplifier is a low noise amplifier.

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