Calculation-based detuning of coupled antennas

Abstract

A user equipment (UE) is provided that detunes a receive antenna while a transmit antenna transmits. To determine the detuning, the UE first transmits a signal through the transmit antenna while sequentially coupling the receive antennas through a known load. At each load, the UE determines an input reflection coefficient for a transmit path to the transmit antenna. Based on the known load and the corresponding input reflection coefficient, the UE determines a load to be coupled to the receive antenna to perform detuning.

Description

Technical Field

[0001] The present disclosure relates generally to wireless communications and, more particularly, to detuning of coupled antennas. Background Art

[0002] In order to achieve higher data rates in modern wireless communication systems such as fifth generation (5G) systems, cellular handsets have evolved to employ antenna arrays. Using antenna arrays has several advantages over using a single antenna. For example, when the received signal strength decreases, the signal-to-noise ratio becomes a limiting factor in the achievable data rate. But the use of multiple receive antennas enables multiple input multiple output (MIMO) and beamforming techniques to increase the received signal strength and thus enhance the achievable data rate. User equipment (UE) such as cellular handsets can therefore use separate transmit and receive antennas.

[0003] As the number of transmit and receive antennas increases, the coupling between antennas may also increase. For example, a transmit antenna may be coupled to a receive antenna so that the transmit power is then dissipated in a low noise amplifier coupled to the receive antenna. Therefore, coupling results in a loss of total radiated power (TRP). But each transmit and receive antenna in a UE may have a unique orientation and position within the UE, which results in different coupling levels between any two antennas. In addition, antenna coupling may change depending on how the user handles the UE. In addition, antenna coupling affects antenna impedance. Therefore, coupling between antennas in a UE is problematic. Summary of the invention

[0004] The following overview discusses some aspects of the present disclosure to provide a basic understanding of the technology discussed. This summary is not an exhaustive overview of all the expected features of the present disclosure, and is neither intended to identify the key or important elements of all aspects of the present disclosure, nor to describe the scope of any or all aspects of the present disclosure. The sole purpose of this summary is to present some concepts of one or more aspects of the present disclosure in a summarized form as a prelude to more specific embodiments presented later.

[0005] According to one aspect of the present disclosure, there is provided an apparatus for wireless communication, the apparatus comprising: a plurality of antennas, the antennas comprising a first antenna and a second antenna; a first amplifier; a plurality of loads; an antenna switching module; an antenna switching array, the antenna switching array having a first configuration, in which the output signal path from the first amplifier is coupled to the first antenna, and in which the antenna switching module is coupled to the second antenna; wherein the antenna switching module is configured to couple to a selected load from the plurality of loads during a calibration mode; and a signal detector, the signal detector being configured to detect a forward signal from the output signal path to provide a detected forward signal, and to detect a reflected signal from the output signal path to provide a detected reflected signal.

[0006] According to another aspect of the present disclosure, a user equipment (UE) for wireless communication is provided, the user equipment (UE) comprising: multiple antennas, the antennas comprising a transmitting antenna and a receiving antenna; a power amplifier; a low noise amplifier; an adjustable load; an antenna switching module, the antenna switching module having a first configuration and a second configuration, in which the antenna switching module is coupled to the low noise amplifier, and in which the antenna switching module is coupled to the adjustable load; an antenna switching array, the antenna switching array having a first configuration, in which the output signal path from the power amplifier is coupled to the transmitting antenna, and in which the antenna switching module is coupled to the receiving antenna; and a signal detector, the signal detector being configured to detect a forward signal from the output signal path and a reflected signal from the output signal path.

[0007] According to another aspect of the present disclosure, a method for wireless communication is provided, the method comprising: propagating a forward signal through a transmission path to transmit the forward signal from a first antenna of a user equipment; coupling a second antenna of the user equipment to each load from a plurality of loads during the transmission of the forward signal from the first antenna; for each load, determining a ratio of a reflected signal from the transmission path to the forward signal to provide a plurality of ratios; determining a scattering parameter in response to a function of the plurality of ratios and the plurality of loads; and detuning the second antenna based on the determination of the scattering parameter.

[0008] Finally, according to another aspect of the present disclosure, a user equipment for wireless communication is provided, which includes: a first antenna; a second antenna; a power amplifier; a directional coupler coupled between the power amplifier and the first antenna; a low noise amplifier; multiple loads; and a controller, which is configured to: when the power amplifier is transmitting through the first antenna, control the second antenna to disconnect from the low noise amplifier and connect to a selected load from the multiple loads.

[0009] After studying the description of the specific exemplary implementation of the present disclosure below in conjunction with the accompanying drawings, other aspects, features and implementations of the present disclosure will be apparent to those of ordinary skill in the art. Although the features of the present disclosure may be discussed below with respect to certain implementations and the accompanying drawings, all implementations of the present disclosure may include one or more of the advantageous features discussed herein. In other words, although one or more implementations are discussed as having certain advantageous features, one or more of such features may also be used according to the various implementations of the present disclosure discussed herein. In a similar manner, although exemplary implementations may be discussed below as device, system or method implementations, it should be understood that such exemplary implementations may be implemented in various devices, systems and methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings are used to further illustrate various specific implementations and explain various principles and advantages according to the present disclosure. In the accompanying drawings, the same figure numbers refer to the same or functionally similar elements throughout the individual views, and the accompanying drawings are incorporated into the specification together with the following specific embodiments and form a part of the specification.

[0011] Figure 1 An example of a system for wireless communication in which a UE can operate a calculation-based detuning according to aspects of the present disclosure is illustrated.

[0012] Figure 2 An example subframe structure including a sounding reference signal portion according to an aspect of the present disclosure is illustrated.

[0013] Figure 3 An example UE configured with adjustable load for calculated based detuning according to one aspect of the present disclosure is illustrated.

[0014] Figure 4 An example UE configured with a fixed load for calculation-based detuning according to one aspect of the present disclosure is illustrated.

[0015] Figure 5 A Smith chart with a profile of detuned gain according to one aspect of the present invention is shown.

[0016] Figure 6 is a flow chart of a method of computation-based detuning according to an aspect of the present disclosure. DETAILED DESCRIPTION

[0017] The following detailed description is intended as a description of various configurations, but is not intended as a description of various configurations, and is not intended to represent the only configurations in which the concepts described herein may be practiced. In order to provide a comprehensive understanding of the various concepts, the specific embodiments include specific details. However, it is apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, in order to avoid obscuring such concepts, well-known structures and components are shown in block diagram form.

[0018] In order to address the mutual coupling between the transmit antenna and the adjacent receive antenna, a wireless communication device (also referred to as user equipment (UE)) is disclosed, which detunes the receive antenna to reduce the mutual coupling. To provide the detuning, each receive antenna can be coupled to the receiver of the UE via an antenna switching module (ASM). The ASM has an operating state and a plurality of known load states. In the operating state (also represented as an operating mode herein), the ASM couples its receive antenna to a receive path in the receiver. Such operation is conventional, so the following discussion will focus on the use of known load states. These known load states are used sequentially during a characterization operating mode in which the transmit antenna is transmitting and mutually coupled to the receive antenna. For example, the characterization mode can include the use of three known load states, as described below.

[0019] In this characterization mode, the directional coupler samples the forward signal propagating from the power amplifier to the transmit antenna and also samples the reflected signal propagating from the transmit antenna back to the power amplifier so that the reflection coefficient can be determined. The reflection coefficient depends on the scattering parameters between the transmit antenna and the receive antenna and the load selected by the antenna switching module. There are four scattering parameters in such a two-port network: the first port corresponds to the input / output terminal for the transmit antenna and the second port corresponds to the input / output terminal for the receive antenna. The first scattering parameter S 11 Indicates how much power is reflected from the first port. The second scattering parameter S 22 Indicates how much power is reflected from the second port. The third scattering parameter S 21 Indicates how much power is coupled from the first port to the second port, and the fourth scattering parameter S 12 Indicates how much power is coupled from the second port to the first port.

[0020] Since the two-port network is passive, the scattering parameter S 21 and S 12equal. Therefore, there are three unknown quantities when characterizing the scattering parameters between the transmit antenna and the receive antenna. As shown in this article, the reflection coefficient is a linear function of these three unknown quantities and the known loads selected by the antenna switching module. Various reflection coefficient measurements are therefore related to the three unknown scattering parameters through linear equations of the three unknown scattering parameters and the corresponding loads. By sequencing these three loads and measuring the corresponding reflection coefficients as determined by sampling the forward and reverse signals at the directional coupler between the power amplifier and the transmit antenna, the UE can then solve for the scattering parameters.

[0021] With the scattering parameters determined, the UE may then determine which of the three loads minimizes the coupling between the transmit antenna and the receive antenna. During subsequent transmissions by the transmit antenna during the detuned portion of the operating mode, the UE may control the antenna switching module to apply the determined load to the receive antenna. The receive antenna is thus detuned relative to the transmit antenna so that the total radiated power from the transmit antenna can be maximized. For example, during subsequent data transmission, the transmitter may modulate a radio frequency (RF) carrier signal with data to obtain a modulated signal, amplify the modulated signal to obtain an output RF signal with an appropriate output power level, filter the output RF signal, and send the output RF signal to the base station via one or more transmit (TX) antennas when the corresponding receive antenna is detuned. During data reception, the UE may control the antenna switching module to select a receive path including a low noise amplifier (LNA), a filter, and other suitable components. During the receive portion of the operating mode in which the receive antenna is used to receive a signal, the antenna switching module does not apply the determined load to the receive antenna. Thus, there are two parts or sub-modes to the operating mode: a detuned part, in which the receive antenna is not used for reception but is instead detuned, and a receive part, in which the receive antenna is used for reception and is therefore not detuned.

[0022] Since the scattering parameters will change as the user handles the UE and in response to changes in other conditions such as beamforming and beam steering, the detuning process can be repeated periodically. During one scattering parameter state, it may be the first load that provides the best detuning, while a different load provides the best detuning during another scattering parameter state. In the detuned state, part of the transmitted power that would otherwise be coupled to the receive path is instead reradiated by the receive antenna, which improves the TRP.

[0023] The signal sent by the UE during the determination of the scattering parameters may be a reference signal. In the UE transceiver, a radio frequency front end circuit (RFFE) may send the reference signal to a transmit antenna. A directional coupler positioned between the RFFE and the transmit antenna may be configured to measure the magnitude and phase of the forward signal and the magnitude and phase of the reverse signal. In some implementations, only the magnitude of the forward signal and the reverse signal is detected.

[0024] In some specific implementations, the antenna switching module may select a tunable load. In the case of determining the scattering parameters, the UE may then adjust the tunable load to an optimal value or a value relatively close to the optimal value to better detune the coupled antenna from the transmit antenna when the transmit antenna is transmitting. Alternatively, the load selected by the antenna switching module may be a fixed load, such as an open circuit, a closed circuit, and a capacitive load. Using the determined scattering parameters, the UE may then select a fixed load from these fixed loads that provides the best detuning. Although such detuning may be suboptimal compared to the adjustment of a variable load, the resulting detuning may be satisfactory and also result in reduced design complexity and cost. Regardless of whether the load is fixed or variable, the calculated detuning is independently packaged within the UE, allowing the UE to dynamically detune during operation. In some configurations, this can reduce or eliminate the need to perform time-consuming TRP measurements in an antenna test range or room before operation.

[0025] The calculation-based detuning techniques as discussed herein may allow a UE to detect coupling between any antenna pair (including TX and RX antennas) by using a reference signal. When one of the TX antennas is transmitting a reference signal, the UE may determine the scattering parameters between the transmit antenna and the receive antenna to find the optimal load to effectively detune the coupling to the receive antenna. The set of optimal loads (or values ​​closest to the optimal loads) for the coupled antennas may be recorded by the UE and used for a period of time after the scattering parameter determination.

[0026] Wireless systems can use various types of reference signals to provide channel estimation for adaptive multi-antenna operations in uplink and / or downlink directions. For example, a channel state information reference signal (CSI-RS) can be used on the downlink from the base station to help the base station perform beamforming, an uplink demodulation reference signal (DM-RS) specific to each UE can be used to estimate the channel information for the uplink, and each UE can use a sounding reference signal (SRS) on the uplink to help with scheduling (e.g., determining which frequency bands are good or bad for data). Taking SRS as an example, the UE can send SRS to the base station sequentially through all its antennas (including TX and RX antennas). The base station can characterize the uplink channel based on the received SRS. Therefore, the RX antenna is used as a transmitting antenna by sending the SRS. Therefore, the antenna coupling measurement disclosed in this article can be applied between any antenna pairs: from the TX antenna to the RX antenna, from the RX antenna to another RX antenna, and so on. It will be understood that although the terms "TX antenna" and "RX antenna" are used herein, there may be times, modes, or configurations when the TX antenna operates to receive and / or there may be times, modes, or configurations when the RX antenna operates to transmit.

[0027] To better appreciate the advantageous properties of this computation-based detuning, aspects of the present disclosure are initially described in the context of a wireless communication system. Figure 1 An example of a wireless communication system 100 that supports computation-based detuning is illustrated. The wireless communication system 100 includes a base station 105, a UE 115, and a core network 130. In some examples, the wireless communication system 100 can be a long term evolution (LTE) network, an advanced LTE (LTE-A) network, an LTE-A Pro network, or a new radio (NR) network. In some cases, the wireless communication system 100 can support enhanced broadband communications, ultra-reliable (e.g., mission-critical) communications, low-latency communications, or communications with low-cost and low-complexity devices. The techniques described herein may be applicable to positioning in 5G NR and future releases, and / or may be applicable to detection of users of UE 115.

[0028] The base station 105 may communicate wirelessly with the UE 115 via one or more base station antennas. The base station 105 described herein may include or may be referred to by those skilled in the art as a base station transceiver, a wireless base station, an access point, a wireless transceiver, a node B, an evolved node B (eNB), a next generation node B or a giga node B (any of which may be referred to as a gNB), a home node B, a home evolved node B, or some other appropriate terminology. The wireless communication system 100 may include different types of base stations 105 (e.g., macro base stations or small cell base stations). The UE 115 described herein is capable of communicating with various types of base stations 105 and network equipment (including macro eNBs, small cell eNBs, gNBs, relay base stations, etc.) and / or is capable of communicating directly with each other.

[0029] Each base station 105 may be associated with a geographic coverage area 110, supporting communications with various UEs 115 in the particular geographic coverage area. Each base station 105 may provide communication coverage for the corresponding geographic coverage area 110 via a communication link 125, and the communication link 125 between the base station 105 and the UE 115 may utilize one or more carriers. The communication link 125 shown in the wireless communication system 100 may include an uplink transmission from the UE 115 to the base station 105, or a downlink transmission from the base station 105 to the UE 115. Downlink transmissions may also be referred to as forward link transmissions, and uplink transmissions may also be referred to as reverse link transmissions.

[0030] One or more UE 115 supports computation-based detuning, as will be further explained herein. Each UE 115 may be dispersed throughout the wireless communication system 100, and each UE 115 may be stationary or mobile. UE 115 may also be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other appropriate term, wherein "device" may also be referred to as a unit, a station, a terminal, or a client. UE 115 may also be a personal electronic device, such as a cellular phone, a personal digital assistant (PDA), a tablet computer, a laptop computer, or a personal computer. In some examples, UE 115 may also refer to a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a machine type communication (MTC) device, etc., which may be specifically implemented in various items such as electrical appliances, vehicles, meters, etc.

[0031] Some UEs 115 (such as MTC or IoT devices) may be low-cost or low-complexity devices and may provide automated communications between machines (e.g., via machine-to-machine (M2M) communications). M2M communications or MTC may refer to data communications technology that allows devices to communicate with each other or with a base station 105 without human intervention. In some examples, M2M communications or MTC may include communications from devices that integrate sensors or meters to measure or capture information and relay the information to a central server or application that may utilize the information or present the information to a person interacting with the program or application. Some UEs 115 may be designed to collect information or implement automated behavior of machines. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business charging.

[0032] The base stations 105 may communicate with the core network 130 and with each other. For example, the base stations 105 may interface with the core network 130 via a backhaul link 132 (e.g., via S1, N2, N3, or other interface). The base stations 105 may communicate with each other directly (e.g., directly between the base stations 105) or indirectly (e.g., via the core network 130) over a backhaul link 134 (e.g., via X2, Xn, or other interface).

[0033] The wireless communication system 100 may operate using one or more frequency bands, such as in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). The 300 MHz to 3 GHz region is referred to as the ultra-high frequency (UHF) region or decimeter band because the wavelengths are in the range of from about 1 decimeter to 1 meter long. UHF waves may be blocked or redirected by buildings and environmental features. However, these waves may penetrate various structures sufficiently so that macro cells provide services to UEs 115 located indoors. Transmission of UHF waves may be associated with smaller antennas and shorter ranges (e.g., less than 100 km) compared to transmission using lower frequencies and longer waves in the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz.

[0034] The wireless communication system 100 may also operate in the very high frequency (SHF) region using frequency bands from 3 GHz to 30 GHz, also known as centimeter bands. The SHF region includes frequency bands that may be opportunistically used by devices that may be able to tolerate interference from other users, such as the 5 GHz Industrial, Scientific, and Medical (ISM) band.

[0035] The wireless communication system 100 may also be operated in the extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz or higher), which is also referred to as the millimeter wave band (which may also include some frequencies in the 20 GHz range in some systems). In some examples, the wireless communication system 100 may support millimeter wave (mmW) communications between the UE 115 and the base station 105, and the EHF antennas of the corresponding devices may be even smaller and more closely spaced than UHF antennas. In some cases, this may facilitate the use of antenna arrays within the UE 115. However, the propagation of EHF transmissions may be subject to even greater atmospheric attenuation and shorter range than SHF or UHF transmissions.

[0036] Each UE 115 is equipped with multiple antennas, which can be used to adopt technologies such as transmit diversity, receive diversity, multiple input multiple output (MIMO) communication or beamforming. For example, the wireless communication system 100 can use a transmission scheme between a transmitter device (e.g., a base station 105 in a downlink) and a receiver device (e.g., a UE 115 in a downlink), wherein the transmitter device is equipped with multiple antennas and the receiver device is equipped with one or more antennas. MIMO communication can use multipath signal propagation to increase spectral efficiency by sending or receiving multiple signals via different spatial layers, which can be referred to as spatial multiplexing. The multiple signals can be sent, for example, by the transmitter device via different antennas or different combinations of antennas. Similarly, the multiple signals can be received by the receiving device via different antennas or different combinations of antennas. Each of the multiple signals can be referred to as a separate spatial stream and can carry bits associated with the same data stream (e.g., the same codeword) or different data streams. Different spatial layers can be associated with different antenna ports for channel measurement and reporting. MIMO technology includes single-user MIMO (SU-MIMO), in which multiple spatial layers are transmitted to the same receiving device, and multi-user MIMO (MU-MIMO), in which multiple spatial layers are transmitted to multiple devices.

[0037] Beamforming (which may also be referred to as spatial filtering, directional transmission, or directional reception) is a signal processing technique that may be used at a sender device or a receiver device (e.g., a base station 105 or a UE 115) to shape or direct an antenna beam (e.g., a transmit beam or a receive beam) along a spatial path between the sender device and the receiver device. Beamforming may be achieved by combining signals communicated via antenna elements of an antenna array so that signals propagating at some orientations relative to the antenna array experience constructive interference, while other signals experience destructive interference. Adjustments to signals communicated via antenna elements may include the sender device or the receiver device applying one or more amplitude and phase offsets to signals carried via each antenna element associated with the device. Adjustments associated with each antenna element may be defined by a set of beamforming weights associated with an orientation (e.g., relative to the antenna array of the sender device or the receiver device, or relative to some other orientation).

[0038] The communication between the UE 115 and the base station 105 can be divided into subframes (SFs) in the time domain. Figure 2 , illustrates an example SF 200 that allocates multiplexed sounding reference signals (SRS). In one embodiment, although the subframe structure 200 operates within a short time frame of approximately 500 microseconds, the short time frame can also be shorter or longer than this microsecond. The short time frame allows the base station 105 to essentially "freeze" the channel state for the duration of the subframe to minimize the effects of channel decorrelation.

[0039] The calculation-based detuning described herein is not limited to any particular type of transmitted signal. The following discussion of using SRS as the transmitted signal used during calculation-based detuning is therefore exemplary only. However, because SRS in 5G systems are sequenced by each TX and RX antenna, it is convenient to use SRS as the transmitted signal during calculation-based detuning. If the calculation-based detuning calculation is performed during SRS transmission, the calculation-based detuning does not require the addition of additional delay compared to conventional SRS operation.

[0040] For ease of explanation, Figure 2200; as will be appreciated, the structure of the SF 200 may be extended to any number of subframes as needed or desired. Each SF 200 includes a plurality of time slots 206, each time slot 206 including a plurality of orthogonal frequency division multiplexing (OFDM) symbols. Each time slot 206 in the SF 200 may be divided into an uplink portion 202 and a downlink portion 204 separated by a transition portion U / D. As part of the uplink portion 202, the UE 115 may transmit various types of signals to the base station 105. These may include, for example, SRS, uplink data, and optionally a request for information (e.g., in an uplink burst). A transition portion U / D is provided between the uplink portion 202 and the downlink portion 204. During the downlink portion 204, the base station 105 transmits various types of signals to the UE 115, including, for example, a user equipment reference signal (UERS) and downlink data (e.g., in a downlink burst). In some embodiments, the base station 105 can use the SRS in the UL portion 202 to derive information that facilitates a downlink between the UE 115 and the base station 105. For example, the base station 105 can train its antenna based on the SRS to beamform downlink data sent back to the UE 115 so that, for example, interference with other UEs within range of the base station 105 is reduced.

[0041] Within a time slot 206, the SRS may span one, two, or four consecutive OFDM symbols within the last six OFDM symbols of the time slot 206. Each antenna may transmit its own SRS so that the sounding reference signal is multiplexed across the antennas of the UE, each antenna having its own SRS in the corresponding time slot 206. Each time slot 206 may include a first cyclic prefix (CP) prepended to the OFDM symbol that multiplexes the SRS. Each time slot 206 may also include a second CP before a guard period before the start of the next time slot. The guard period ensures that the UE 115 has enough time to perform SRS antenna switching. Figure 2Also illustrated in the figure are the timing of SRS antenna switching and calculation-based detuning. At the beginning of time slot 206, the SRS switching antenna switching is configured to couple the transmission path to the selected antenna in preparation for transmitting the multiplexed SRS. When the selected antenna begins to transmit the multiplexed SRS, the calculation-based detuning is also performed ("ON"). In some specific implementations, the duration of the calculation-based detuning of one coupled antenna is shorter than the transmission of the multiplexed SRS by the selected antenna, so that the detuning is completed before the start of the second CP preceding the protection period ("OFF"). The calculation-based detuning of another pair of coupled antennas (or the same pair) begins with the subsequent transmission of the multiplexed SRS. For example, the first SRS transmission on the OFDM symbol in the first time slot 206 can be used to determine the coupling and detuning between the first pair of antennas, the second SRS transmission in the second time slot 206 can be used to determine the coupling and detuning between the second pair of antennas, and so on. In some examples, the antennas in the first pair of antennas are also included in the second pair of antennas.

[0042] Figure 2 The four time slots 206 shown in are for illustrative purposes and not for limitation. The number of SRS transmissions for calculated detuning may be greater or less than the four SRS transmissions in sequence, depending on the number of antennas that need to be detuned in the UE 115. In addition, depending on the desired calculated detuning update or refresh, the multiplexed SRS transmission sequence and the corresponding calculated detuning may be repeated over time. The repeated SRS transmission also allows the UE 115 to collect the best detuning settings for the same antenna multiple times at different repeated time slots 206, and average these values ​​to provide improved detuning. In the time slot 206, the multiplexed SRS may be the same for each antenna. Alternatively, the multiplexed SRS may be unique for each antenna, so that the base station 105 can identify which antenna is transmitting the corresponding received SRS. As shown, it may be performed in continuous time slots, or it may be performed in discontinuous time slots or only in certain selected time slots (e.g., based on the determination that it will be beneficial to update one or more parameters between a certain antenna pair). Some example UE architectures for calculated detuning will now be discussed in more detail.

[0043] Calculation-based detuning with adjustable load

[0044] As previously described, a pair of antennas characterized by a calculated detuning can be viewed as forming a two-port network. The input / output terminal to the first antenna forms the first port of the two-port network, while the input / output terminal to the second antenna forms the second port. The antenna switching module switches so that different loads are sequentially applied to the second port while the transmitter drives the first port so that the first antenna transmits. A directional coupler coupled to the first port measures or determines the reflection coefficient. Based on the measured reflection coefficient and the known load, the UE can then determine the scattering parameters of the two-port network in this example and detune the second antenna accordingly.

[0045] In one specific implementation, the antenna switching module can be coupled to the adjustable load during the calculated detuning period. The antenna switching module thus does not need to switch to select from one load to another, but instead the adjustable load is adjusted to provide (e.g., three) different loads. Figure 3 An example UE 300 with computation-based detuning using an adjustable load 384 is shown in . In this example, the UE 300 includes a data processor 310, a transceiver 320, an antenna switching array 350, and a plurality of antennas including an antenna 362 and an antenna 364. The data processor 310 may also be embodied as a modem. The transceiver 320 includes a transmitter 330 and a receiver 340 that support bidirectional wireless communication. In a transmit path, the data processor 310 processes (e.g., encodes and modulates) data to be transmitted and provides an analog output signal to the transmitter 330. A memory 312 of the processor 310 may store program code and data for the data processor 310. A transmit power controller 314 may control the transmit power of the transceiver 320. A detuning controller 316 may control the on / off state of switches in the antenna switching array 350 and in the antenna switching module 380. Each of the memory 312, the transmit power controller 314, and the detuning controller 316 may be internal to the data processor 310 (e.g., Figure 3 ) or external to data processor 310. Although element 380 is referred to herein as an antenna switching module, it will be understood that its components need not be packaged together in a hardware module. The components may be included in circuits or chips that are not packaged as modules, or may be implemented separately. Similarly, the above description of the antenna switching module does not require that such functionality be implemented by components packaged together in a hardware module.

[0046] Within transmitter 330, TX circuit 332 amplifies, filters, and up-converts the output signal from baseband to RF and provides a modulated signal. TX circuit 332 may include amplifiers, filters, mixers for up-conversion from baseband to RF, oscillator circuits, local oscillator (LO) generators, phase-locked loops (PLLs), and other suitable components. Power amplifier (PA) 334 receives and amplifies the modulated signal and provides an amplified RF signal with an appropriate output power level as controlled by transmit power controller 314.

[0047] The antenna switching array 350 is configured to select a pair of antennas, such as antennas 362 and 364. One of the antennas will be selected by the antenna switching array 350 so that during the calculated detuning of the second antenna coupled to the antenna switching module 380, it is the first antenna that is coupled to the transmitter 330. For example, the antenna switching array 350 may have a first configuration in which the transmitter 330 is coupled to the antenna 362 and in which the input terminal of the antenna switching module 380 is coupled to the antenna 364. Similarly, the antenna switching array 350 may have a second configuration in which the transmitter 330 is coupled to the antenna 364 and in which the input terminal of the antenna switching module 380 is coupled to the antenna 362. The first configuration may be considered a "through" configuration, while the second configuration may be considered a "cross" configuration.

[0048] During the operation mode (no calculation-based detuning), in which the second antenna is not detuned but instead receives a signal, the antenna switching module 380 couples from this second antenna selected by the antenna switching array 350 to the receiver 340. In the receive path of the receiver 340, the received RF signal from the selected antenna (or multiple antennas) is amplified by the low noise amplifier (LNA) 342. The LNA output signal from the LNA 342 is processed by the RX circuit 346 to provide an analog baseband input signal to the data processor 310. The RX circuit 346 may include amplifiers, filters, mixers for down-converting from RF to baseband, oscillators, LO generators, PLLs, and other suitable components. In the characterization mode for calculation-based detuning, the antenna switching module 380 is instead configured to couple the second antenna (e.g., antenna 364 or antenna 362) in the 2-port network being characterized to the adjustable load 384. Similarly, antenna switching module 380 also couples the second antenna to adjustable load 384 during the operating mode when the second antenna is detuned for reception. Adjustable load 384 may be implemented with any number of components, such as an adjustable inductor, a switched capacitor network, and the like.

[0049] In the following discussion, without loss of generality, it is assumed that antenna 362 is the first antenna in the two-port network and antenna 364 is the second antenna. Antenna switching module 380 is therefore configured to pass a configuration in which switch port 352 is the first port of antenna 362 and switch port 354 is the second port of antenna 364.

[0050] To measure the reflection coefficient during the characterization mode, the UE 300 includes a directional coupler 372 coupled between the switch port 352 and the power amplifier 334. The directional coupler 372 samples the forward signal propagating from the power amplifier 334 to the antenna 362, and also samples the reflected signal reflected from the switch port 352 back to the power amplifier 334. The signal detector 376 determines the ratio of the reflected signal to the forward signal to form the reflection coefficient of the switch port 352. The reflection coefficient can also be expressed as Γ IN In one implementation, the signal detector 376 may detect both the amplitude and phase of the forward and reflected signals such that Γ IN is a complex number. In other specific implementations, the signal detector 376 may only detect the magnitude of the forward and reflected signals, so that Γ IN is a real number. A smaller input reflection coefficient translates into a better match for the transmit antenna. For example, Γ IN =0 means no reflected power.

[0051] The directional coupler 372 can receive a forward RF signal at a first port P1, provide an output RF signal at a second port P2, and provide a sample of the forward signal at a third port P3. The directional coupler 372 can also provide a sample of the reflected RF signal at a fourth port P4. The signal detector 376 can be a square law power detector, a phase and amplitude signal detector, or another suitable type of signal detector. The signal detector 376 can receive RF signals at different ports of the directional coupler 372, and can measure the voltage, current, power, and / or other characteristics of the RF signal. The signal detector 376 can be coupled to the third port and the fourth port through the switch 374. The signal detector 376 can also measure the forward signal propagated to the switch port 352 or the reflected signal from the switch port 352 based on the state of the switch 374. The switch 374 can be a "2" knife "2" throw (DPDT) switch. In one state, the switch 374 connects the antenna side of the directional coupler 372 to a matching load coupled to ground, and connects the amplifier side of the directional coupler 372 to the detector 376. In another state, switch 374 connects the antenna side of directional coupler 372 to detector 376 and connects the amplifier side of directional coupler 372 to a terminating impedance such as a matched load.

[0052] By using one directional coupler 372 in conjunction with a switch 374, a single directional coupler may be used instead of two directional couplers to perform signal measurements on a transmit line as described herein. The switch 374 switches between ports on the directional coupler 372 to allow measurements in either direction, i.e., measurements of signals from the PA 334 and measurements of signals reflected back from a transmit antenna in the antenna, such as during transmission of an SRS or other suitable signal.

[0053] During transmission from the first antenna, when the switch 374 is set in the first state, the directional coupler 372 is responsive to the voltage V indicative of the forward signal. f When the switch 374 is set in the second state, the directional coupler 372 senses the voltage V indicating the reflected signal. r More specifically, in some implementations, when the switch 374 is configured such that the port P4 is coupled to the termination impedance and the port P3 of the directional coupler 372 is fed into the signal detector 376, a voltage V indicating the forward signal may be measured. f Since power is a function of voltage and current, the voltage V f Proportional to the forward power. Conversely, when switch 374 is configured such that port P4 is coupled to detector 376 and port P3 is coupled to the terminating impedance, a voltage V indicative of the reflected signal can be measured. r As mentioned above, since power is a function of voltage and current, the voltage V r Proportional to reverse power.

[0054] In determining the voltage V f and voltage V r Afterwards, the ratio V can be determined r / V f As described in this article, a single directional coupler can be used to generate a voltage V r and V f Voltage V r and V f are proportional to the forward power and reflected power respectively. The input reflection coefficient is defined in the following equation (1):

[0055] Γ IN＝ V r / V f Equation (1)

[0056] Input reflection coefficient Γ IN It can be used to determine other quality factors that describe the RF channel, such as the voltage standing wave ratio (VSWR). VSWR is defined by the following equation (2):

[0057] VSWR=(1+|Γ IN │) / (1-│ΓIN │)Equation (2)

[0058] In some implementations, the signal detector 376 can detect the f and V r The input reflection coefficient Γ is calculated by measuring IN and / or other quality factors (e.g., VSWR), and reports the calculated results to the data processor 310, such as controlled by the detuning controller 316. In some implementations, the signal detector 376 includes a V r and V f The analog-to-digital converter (ADC) measures and digitizes and provides their digitized value. r and V f The digitized value of can be sent to the data processor 310. The circuit within the data processor 310 can store this information so that the input reflection coefficient Γ can be calculated. IN and / or other relevant quality factors.

[0059] Γ IN Smaller values ​​of indicate fewer reflections and better matching between the antenna and the radio (or the antenna and the transmission line). From equation (1) above, it can be determined that the lowest possible value of the input reflection coefficient is 0. When the input reflection coefficient is 0, no reflection occurs, i.e., the antenna and the radio or the antenna and the transmission medium are perfectly matched. Therefore, when Γ IN When it is 0, no power is reflected. As the reflection increases, Γ IN Increase. Performance can be increased with Γ IN Therefore, the lower the Γ IN To address these mismatches, UE 115 may include an antenna tuning network (e.g., a tuner, not shown) coupled to the antenna to improve the performance of the antenna at Γ. IN and / or other quality factors (e.g., VSWR) in the light of the antenna impedance match. If the signal detector 376 is capable of detecting complex values, then use Γ IN Both the real and imaginary components of can improve the tuning process.

[0060] However, because the transmitted power is coupled to other antennas and dissipated in circuits such as LNA 342, it is radiated into the air instead, so minimizing Γ IN may not directly translate into maximizing TRP. Therefore, to better detune the coupled antenna, the input reflection coefficient Γ is determined separately IN The calculation-based detuning disclosed herein advantageously determines the scattering parameters between the transmit antenna and the coupled receive antenna so that the detuning of the coupled receive antenna can be improved.

[0061] The operation of the data processor 311 based on the input reflection coefficient Γ will now be discussed in more detail. IN Calculate scattering parameters. In order to calculate the scattering parameters, the detuning controller 316 sets the adjustable load 384 to a first impedance value and performs a first measurement of the input reflection coefficient. The adjustable load 384 is then set to a second impedance value and a second measurement of the input reflection coefficient is performed. Finally, the adjustable load 384 is set to a third impedance value and a third measurement of the input reflection coefficient is performed. Each of these measurements can occur during the transmission of a corresponding reference signal. If a separate reference signal is used, there will be three separate reference signal transmissions for the three measurements. Alternatively, two (or all three) of the measurements can be performed during the transmission of a single reference signal. Based on the three measurement results, the data processor 310 calculates the scattering parameters S11, S22, S21, and S12. Relative to this calculation, the impedance of the adjustable load 384 determines the load reflection coefficient Γ L , which is a function of the adjustable load impedance 384 and the characteristic impedance. Therefore, the impedance of the adjustable load 384 can be converted into the load reflection coefficient by the data processor 310. Then, the calculation of the scattering parameters can use the input reflection coefficient Γ IN and the load reflection coefficient Γ L The relationship between them is given by the following equation (3):

[0062]

[0063] Scattering parameter S 11 , S 22 Sum product S 12 *S 21 A two-port channel between TX antenna 362 and RX antenna 364 is depicted. To simplify notation, the input reflection coefficient Γ IN It can also be expressed as M (a measure of the input reflection coefficient). Similarly, the load reflection coefficient Γ L It can be expressed as L. Therefore, equation (3) can be rewritten as the following equation (4):

[0064] M=S 11 +MLS 22 +L(S 12 S 21 -S 11 S 22 ) Equation (4)

[0065] A first input reflection coefficient measurement M1 is then performed using an adjustable load 384 configured to provide a first load reflection coefficient L1. Similarly, a second measurement value M2 is measured using a second load reflection coefficient L2. Finally, a third measurement value M3 is measured using a third load reflection coefficient L3. From the values ​​M1, M2, M3, L1, L2, and L3, the corresponding three versions of equation (4) can be solved to determine the three unknown quantities S 11 , S 22 and S 12 *S 21 Then we can get the value from (S 12 *S 21 ) determines the scattering coefficient S 21 (or S 12 ).

[0066] These three versions of equation (4) can be written in matrix form as shown in equation (6) below:

[0067]

[0068] Where Δ=S 12 S 21 -S 11 S 22 .

[0069] Therefore, the two-port scattering parameters can be calculated based on equation (5) using a method of solving three linear equations with three unknowns. Once the two-port scattering parameters are calculated, the two-port channel represented by the two-port scattering parameters is characterized.

[0070] Given the values ​​M1, M2, and M3 corresponding to L1, L2, and L3, data processor 310 can solve equation (5) to obtain the scattering parameters describing the two-port channel from transmit antenna 362 to receive antenna 364. Since the two-port channel is characterized, data processor 310 can also calculate the optimal load that most effectively detunes antenna 364, such as described herein with respect to Figure 5 Further discussion. At the end of the characterization mode prior to the operating mode, the detuning controller 318 can set the adjustable load 384 to the optimal load or to a value in the adjustable range that is closest to the optimal load. The coupling between the antennas 362 and 364 is thus advantageously minimized or reduced so that the total radiated power from the UE 300 is increased or maximized when the antenna 362 transmits during the detuned portion of the operating mode. Note that during the receive portion of the operating mode in which the antenna 364 receives a signal coupled to the receive path of the receiver 340, the antenna 364 will not be detuned. An alternative embodiment will now be discussed in which the adjustable load 384 is replaced by three fixed loads.

[0071] Calculation-based detuning with fixed load

[0072] exist Figure 4 An example UE 400 with calculation-based detuning using a fixed load is shown in FIG. Antennas 362 and 364, switch array 350, transceiver 320, directional coupler 372, and switch 374 are arranged as discussed for UE 300. However, antenna switching module 480 no longer selects between a receive path to LNA 342 and an adjustable load to couple the selected element to switch port 354. Instead, antenna switching module 480 has a first configuration in which switch port 354 is coupled to the receive path, a second configuration in which switch port 345 is coupled to capacitor 486 having a known capacitance, a third configuration in which switch port 354 is coupled to a termination impedance such as 50Ω via short circuit 485, and a fourth configuration in which switch port 354 is open circuit from these elements. The second configuration, the third configuration, and the fourth configuration are used during the calculation mode. If the antenna 364 is used to receive during the receive portion of the operating mode, the antenna switching module 380 uses the first configuration.

[0073] In the calculation mode, the load reflection coefficient is thus determined by the sequential selection of the open circuit, the short circuit 485, and the capacitor 486. Since adjustable loads are typically more expensive and complex components than passive capacitors and short circuits, the use of fixed loads can reduce manufacturing costs and complexity. The data processor 410 is similar to the data processor 310 and therefore includes a memory 312 and a transmit power controller 314. As discussed for the UE 300, the detuning controller 416 controls the antenna switching array 350. In addition, the detuning controller 416 controls the antenna switching module 480 to sequentially select each fixed load (open circuit, capacitor 486, and short circuit 485) during the calculation of the scattering parameters. Each selected fixed load corresponds to a load reflection coefficient. The detuning controller 416 can therefore calculate the scattering parameters similarly to what is discussed above for equation (5).

[0074] In this example, antenna 362 again forms the first antenna, while antenna 364 forms the second antenna. However, this choice is arbitrary, so that antenna 364 can be the first antenna (transmit antenna in the characterized two-port network) and antenna 362 can be the second antenna (receive antenna in the characterized two-port network).

[0075] In a first measurement M1 of the input reflection coefficient at the directional coupler 372, such as during transmission of a first reference signal, the detune controller 416 may configure the antenna switching module 480 so that the switch port 354 is open circuit relative to the receive path to the LNA 342, the capacitor 486, and the short circuit 485. The resulting disconnection of the antenna 364 from any load is also denoted herein as the “OPEN” load L1. A first reflection coefficient measurement M1 may then be made. Subsequently, the detune controller 416 may configure the antenna switching module 480 to couple the switch port 354 (and thus the antenna 364) to the capacitor 486. The capacitance of the capacitor 486 is a known value and acts as a second load L2, also denoted herein as “CAP”. A second reflection coefficient measurement M2 may then be performed, for example, during transmission of the first reference signal (or during transmission of the second reference signal if the first reference signal duration is not long enough for two separate reflection coefficient measurements). Finally, the detune controller 416 can configure the antenna switching module 480 to couple the switch port 354 (and therefore the antenna 364) to the terminating impedance via the short circuit 485. This load L3 is also denoted herein as "SHORT". A third reflection coefficient measurement M3 can then be performed, such as during the first reference signal transmission, during the second reference signal transmission, or during the third reference signal transmission, depending on the time required to perform the reflection coefficient measurement and the duration of the reference signal transmission. Once the data processor 410 obtains the values ​​of M1, M2, and M3 corresponding to L1, L2, and L3, it can solve equation (5) to calculate the scattering parameters describing the two-port channel between antennas 362 and 364. Since the scattering parameters are then determined, the data processor 310 can determine which of the three fixed loads OPEN, SHORT, and CAP provides the greatest detuning, such as relative to Figure 5 As described. At the end of the calculation mode, the detuning controller 416 can then configure the antenna switching module 480 to select the appropriate load accordingly. Although the use of three known loads is described with respect to certain examples above in order to calculate a set of scattering parameters, a larger number of loads can be utilized (e.g., when in a configuration with more than two ports and / or more than three unknown scattering parameters). Alternatively, less than three loads can be used (e.g., when certain scattering parameters are known or characterized by another method or process).

[0076] For each load, the detuning can be defined in terms of the load impedance relative to the power drawn by the two-port network. Contours of equal detuned gain are plotted in 0.1 dB increments as shown in Figure 5The Smith chart shown. The center contour through the normalized impedance of 1.0 corresponds to 0 dB detuned gain. Such detuned gain is undesirable because it corresponds to a highly coupled state in which less power is radiated from the first antenna into free space. The SHORT load corresponds most closely to the contour with a detuned gain of 0.4 dB. The CAP load corresponds most closely to the contour representing 0.7 dB of detuned gain. Finally, the OPEN load corresponds most closely to the contour representing 0.8 dB of detuned gain. Therefore, during the detuned portion of the operating mode, the OPEN load will be selected as the load for the coupled antenna.

[0077] As discussed with respect to UE 300, similar detuning may occur using adjustable load 384. After the calculation mode has determined the scattering parameters so that the optimal detuned load can be determined, UE 300 may transition into the detuned portion of the operating mode. In this state, detuning controller 316 may set adjustable load 384 to provide the optimal detuned load. If the tuning range of adjustable load 384 does not cover the optimal detuned load, controller 316 may set adjustable load 384 to the value within its tuning range that is closest to the optimal detuned load.

[0078] Now refer to Figure 6 600. The method includes an action 600 of propagating a forward signal through a transmit path to transmit the forward signal from a first antenna of a user equipment. The operation of UE 300 and UE 400 when antenna 362 transmits during the calculation mode is an example of action 600. The method also includes an action 605 that occurs during action 600 and includes coupling a second antenna of the user equipment to each load from a plurality of loads. An example of action 605 is that antenna 364 in UE 300 is coupled to an adjustable load 384, and adjustable load 384 is sequenced by three different load values. Similarly, coupling antenna 364 in UE 400 to a sequence through an open circuit, capacitor 486, and short circuit 485 is another example of action 605. The method also includes an action 610 for each load of action 605. Action 610 includes determining a ratio of a reflected signal from a transmit path to a forward signal of the transmit path to provide a plurality of ratios. The operation of the signal detector 376 and the detune controller 316 (or 416) to determine the ratios is an example of action 610. In addition, the method includes an action 615 to determine scattering parameters in response to the function of the plurality of ratios and the plurality of loads. The calculation of the scattering parameters determined by the data processor 310 or 410 is an example of action 615. Finally, the method includes an action 620 to detune the second antenna based on the determination of the scattering parameters. Detuning the antenna 364 in the UE 300 or 400 is an example of action 620.

[0079] The present disclosure will now be summarized in the following exemplary clauses.

[0080] Clause 1. An apparatus for wireless communication, the apparatus comprising:

[0081] a plurality of antennas, the plurality of antennas comprising a first antenna and a second antenna;

[0082] First amplifier;

[0083] Multiple loads;

[0084] Antenna switching module;

[0085] an antenna switching array having a first configuration in which an output signal path from the first amplifier is coupled to the first antenna and in which the antenna switching module is coupled to the second antenna;

[0086] wherein the antenna switching module is configured to couple to a selected load from the plurality of loads during a calibration mode;

[0087] and

[0088] A signal detector is configured to detect a forward signal from the output signal path to provide a detected forward signal, and to detect a reflected signal from the output signal path to provide a detected reflected signal.

[0089] Clause 2. The apparatus of clause 1, wherein the plurality of loads comprises three loads.

[0090] Clause 3. The apparatus of clause 2, wherein a first load from among the three loads comprises a capacitor.

[0091] Clause 4. The apparatus of clause 2, wherein a second load from the three loads comprises an open circuit.

[0092] Clause 5. The apparatus of clause 2, wherein a third load from the three loads comprises a short to ground.

[0093] Clause 6. The apparatus of clause 2, wherein a first load from the three loads comprises a capacitor, a second load from the three loads comprises an open circuit, and a third load from the three loads comprises a short to ground.

[0094] Clause 7. The apparatus according to any one of clauses 2 to 6, further comprising:

[0095] a controller configured to control the antenna switching module to sort the selected loads through the three loads and determine a corresponding input reflection coefficient at each value of the selected loads, the input reflection coefficient being equal to a ratio of the detected forward signal to the detected reflected signal to provide three input reflection coefficients.

[0096] Clause 8. The apparatus of Clause 7, wherein the controller is further configured to determine a scattering parameter of a coupling between the first antenna and the second antenna in response to the function of the three input reflection coefficients.

[0097] Clause 9. The apparatus of clause 8, wherein the controller is further configured such that the function also depends on the three loads.

[0098] Clause 10. The apparatus of any of clauses 8 to 9, wherein the controller is further configured to control the antenna switching module to couple to one of the three loads to detune the second antenna during a detune portion of an operating mode.

[0099] Clause 11. The apparatus of any of clauses 1 to 10, wherein the antenna switching array is further configured in a second configuration to couple the output signal path from the first amplifier to the second antenna and to couple the antenna switching module to the first antenna.

[0100] Clause 12. An apparatus as recited in any one of Clauses 1 to 11, wherein the apparatus comprises user equipment.

[0101] Clause 13. The apparatus of clause 10, further comprising:

[0102] a second amplifier, wherein the first antenna is a transmit antenna of the device and the second antenna is a receive antenna of the device, and wherein the antenna switching module is further configured to couple to the second amplifier during a receive portion of the operating mode.

[0103] Clause 14. The apparatus of clause 13, wherein the first amplifier is a power amplifier, and wherein the second amplifier is a low noise amplifier.

[0104] Clause 15. The apparatus according to any one of clauses 1 to 14, further comprising:

[0105] A directional coupler is coupled to the output signal path of the first amplifier.

[0106] Clause 16. The apparatus of Clause 15, wherein the signal detector is configured to selectively couple to a first port of the directional coupler to detect the forward signal and to selectively couple to a second port of the directional coupler to detect the reflected signal.

[0107] Clause 17. An apparatus for wireless communication, the apparatus comprising:

[0108] A plurality of antennas, wherein the plurality of antennas include a transmitting antenna and a receiving antenna;

[0109] Power amplifier;

[0110] Low noise amplifier;

[0111] Adjustable load;

[0112] an antenna switching module, the antenna switching module having a first configuration and a second configuration, wherein in the first configuration the antenna switching module is coupled to the low noise amplifier and in the second configuration the antenna switching module is coupled to the adjustable load;

[0113] an antenna switching array having a first configuration in which an output signal path from the power amplifier is coupled to the transmit antenna and in which the antenna switching module is coupled to the receive antenna; and

[0114] A signal detector is configured to detect a forward signal from the output signal path and a reflected signal from the output signal path.

[0115] Clause 18. The apparatus of clause 17, further comprising:

[0116] A controller is configured to adjust the adjustable load to sequence through a plurality of load values ​​and to determine an input reflection coefficient based on a ratio of the forward signal to the reflected signal at each load value.

[0117] Clause 19. An apparatus according to clause 18, wherein the controller is further configured to cause the multiple load values ​​to be equal to three load values ​​and determine three corresponding input reflection coefficients, and wherein the controller is further configured to determine a scattering parameter in response to a function of the three load values ​​and the three corresponding input reflection coefficients.

[0118] Clause 20. The apparatus of Clause 19, wherein the controller is further configured to adjust the adjustable load to detune the receive antenna in response to the determination of the scattering parameter.

[0119] Clause 21. A method for wireless communication, the method comprising:

[0120] propagating a forward signal through a transmit path to transmit the forward signal from a first antenna of the user equipment;

[0121] coupling a second antenna of the user equipment to each load from a plurality of loads during transmission of the forward signal from the first antenna;

[0122] for each load, determining a ratio of a reflected signal from the transmit path to the forward signal to provide a plurality of ratios;

[0123] determining a scattering parameter in response to a function of the plurality of ratios and the plurality of loads; and

[0124] The second antenna is detuned based on the determination of the scattering parameter.

[0125] Clause 22. The method of clause 21, wherein detuning the second antenna comprises coupling the second antenna to a selected load from the plurality of loads.

[0126] Clause 23. The method according to any one of Clauses 21 and 22, further comprising:

[0127] A data signal is transmitted through the first antenna while the second antenna is detuned.

[0128] Clause 24. The method of any one of clauses 21 to 23, wherein the plurality of loads comprises an open circuit, a short circuit to ground, and a capacitor.

[0129] Clause 25. A user equipment for wireless communication, the user equipment comprising:

[0130] First antenna;

[0131] Second antenna;

[0132] Power amplifier;

[0133] a directional coupler coupled between the power amplifier and the first antenna;

[0134] Low noise amplifier;

[0135] Multiple loads; and

[0136] A controller, the controller being configured to:

[0137] When the power amplifier is transmitting through the first antenna, the second antenna is controlled to be disconnected from the low noise amplifier and connected to a selected load from among the plurality of loads.

[0138] Clause 26. The user equipment of clause 25, wherein the selected load increases a gain of the first antenna.

[0139] Clause 27. The user equipment of clause 25, wherein the controller is further configured to:

[0140] The second antenna is connected to the low noise amplifier when the power amplifier is not transmitting through the first antenna.

[0141] Clause 28. User equipment as recited in any one of Clauses 25 to 27, wherein the plurality of loads comprises capacitors and shorts to ground.

[0142] Clause 29. The user equipment of clause 28, wherein the plurality of loads further comprises an open circuit.

[0143] It should be noted that the methods described herein describe possible implementations, and that the various operations and steps may be rearranged or otherwise modified and that other implementations are possible. Furthermore, aspects from two or more methods may be combined.

[0144] The descriptions set forth herein in conjunction with the accompanying drawings describe example configurations and do not represent all examples that can be implemented or within the scope of the claims. Specific embodiments include specific details for providing an understanding of the described techniques. However, these techniques can be practiced without these specific details. In some cases, in order to avoid blurring the concepts of the described examples, well-known structures and devices are shown in block diagram form. In order to enable those skilled in the art to implement or use the present disclosure, the description herein is provided. It will be apparent to those skilled in the art that various modifications to the present disclosure will be apparent, and the general principles defined herein may be applied to other variations without departing from the scope of the present disclosure. Thus, the present disclosure is not limited to the examples and designs described herein, but should be granted the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A device for wireless communication, the device comprising: a plurality of antennas, the plurality of antennas comprising a first antenna and a second antenna; First amplifier; Multiple loads; Antenna switching module; an antenna switching array having a first configuration in which an output signal path from the first amplifier is coupled to the first antenna and in which an input terminal of the antenna switching module is coupled to the second antenna; wherein the antenna switching module is configured to couple to a selected load from the plurality of loads during a calibration mode; and A signal detector is configured to detect a forward signal from the output signal path to provide a detected forward signal, and to detect a reflected signal from the output signal path to provide a detected reflected signal.

2. The apparatus of claim 1, wherein the plurality of loads comprises three loads. 3 . The apparatus of claim 2 , wherein a first load from among the three loads comprises a capacitor.

4. The apparatus of claim 2, wherein a second load from among the three loads comprises an open circuit.

5. The apparatus of claim 2, wherein a third load from among the three loads comprises a short to ground.

6. The apparatus of claim 2, wherein a first load from among the three loads comprises a capacitor, a second load from among the three loads comprises an open circuit, and a third load from among the three loads comprises a short to ground.

7. The device according to claim 6, further comprising: a controller configured to control the antenna switching module to sort the selected loads through the three loads and determine a corresponding input reflection coefficient at each value of the selected loads, the input reflection coefficient being equal to a ratio of the detected forward signal to the detected reflected signal to provide three input reflection coefficients.

8. The apparatus of claim 7, wherein the controller is further configured to determine a scattering parameter describing coupling between the first antenna and the second antenna in response to the function of the three input reflection coefficients.

9. The apparatus of claim 8, wherein the controller is further configured such that the function also depends on the three loads.

10. The apparatus of claim 8, wherein the controller is further configured to control the antenna switching module to couple to one of the three loads to detune the second antenna during a detune portion of an operating mode.

11. The apparatus of claim 1, wherein the antenna switching array is further configured in a second configuration to couple the output signal path from the first amplifier to the second antenna and to couple the antenna switching module to the first antenna.

12. The apparatus of claim 1, wherein the apparatus comprises user equipment.

13. The device according to claim 10, further comprising: a second amplifier, wherein the first antenna is a transmit antenna of the apparatus and the second antenna is a receive antenna of the apparatus, and wherein the antenna switching module is further configured to couple to the second amplifier during a receive portion of the operating mode.

14. The apparatus of claim 13, wherein the first amplifier is a power amplifier and the second amplifier is a low noise amplifier.

15. The apparatus according to claim 1, further comprising: A directional coupler is coupled to the output signal path of the first amplifier. 16 . The apparatus of claim 15 , wherein the signal detector is configured to selectively couple to a first port of the directional coupler to detect the forward signal, and to selectively couple to a second port of the directional coupler to detect the reflected signal.

17. An apparatus for wireless communication, the apparatus comprising: A plurality of antennas, wherein the plurality of antennas include a transmitting antenna and a receiving antenna; Power amplifier; Low noise amplifier; Adjustable load; an antenna switch module having a first configuration and a second configuration, wherein in the first configuration the antenna switch module is coupled to the low noise amplifier and in the second configuration the antenna switch module is coupled to the adjustable load; an antenna switching array having a first configuration in which an output signal path from the power amplifier is coupled to the transmit antenna and in which the antenna switching module is coupled to the receive antenna; and A signal detector is configured to detect a forward signal from the output signal path and a reflected signal from the output signal path.

18. The apparatus according to claim 17, further comprising: A controller is configured to adjust the adjustable load to sequence through a plurality of load values ​​and to determine an input reflection coefficient based on a ratio of the forward signal to the reflected signal at each load value.

19. The apparatus of claim 18, wherein the controller is further configured to cause the plurality of load values ​​to equal three load values ​​and determine three corresponding input reflection coefficients, and wherein the controller is further configured to determine a scattering parameter in response to a function of the three load values ​​and the three corresponding input reflection coefficients.

20. The apparatus of claim 19, wherein the controller is further configured to adjust the adjustable load to detune the receive antenna in response to the determination of the scattering parameter.

21. A method for wireless communication, the method comprising: propagating a forward signal through a transmit path to transmit the forward signal from a first antenna of the user equipment; coupling a second antenna of the user equipment to each load from a plurality of loads during transmission of the forward signal from the first antenna; for each load, determining a ratio of a reflected signal from the transmit path to the forward signal to provide a plurality of ratios; determining a scattering parameter in response to a function of the plurality of ratios and the plurality of loads; as well as The second antenna is detuned based on the determination of the scattering parameter.

22. The method of claim 21, wherein detuning the second antenna comprises coupling the second antenna to a selected load from the plurality of loads.

23. The method according to claim 21, further comprising: A data signal is transmitted through the first antenna while the second antenna is detuned.

24. The method of claim 21, wherein the plurality of loads comprises an open circuit, a short circuit to ground, and a capacitor.

25. A user equipment for wireless communication, the user equipment comprising: First antenna; Second antenna; Power amplifier; a directional coupler coupled between the power amplifier and the first antenna; Low noise amplifier; Multiple loads; and A controller, the controller being configured to: When the power amplifier is transmitting through the first antenna, the second antenna is controlled to be disconnected from the low noise amplifier and connected to a selected load from among the plurality of loads.

26. The user equipment of claim 25, wherein the selected load increases a gain of the first antenna.

27. The user equipment of claim 25, wherein the processor is further configured to: The second antenna is connected to the low noise amplifier when the power amplifier is not transmitting through the first antenna.

28. The user equipment of claim 25, wherein the plurality of loads comprises capacitors and shorts to ground.

29. The user equipment of claim 28, wherein the plurality of loads further comprises an open circuit.

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