Apparatus and method for communication

Abstract

The invention relates to an apparatus and method for communication. The invention discloses a device and method for achieving special thermal density reduction through antenna thin cloth and a computer readable medium. In one embodiment, a system includes N transmit / receive (TX / RX) chains, where each TX / RX chain includes an RFFE and each RFFE includes one or more thermal sensors configured to measure heat in the RFFE. An antenna array is coupled to the plurality of TX / RX chains. Comprising a plurality of codewords configured to respond to real-time thermal measurements from the thermal sensors in each TX / RX chain and configured to turn off the selected TX / RX chain to reduce thermal density at the antenna array while keeping the M RFFEs on, where Mlt; n and the desired beamforming gain is 10 log10 (M).

Description

[0001] Related Applications Citations

[0002] This application is a divisional application of the invention patent application with international application number PCT / US2018 / 040441, international application date June 29, 2018, date of entry into the Chinese national phase on October 9, 2020, Chinese national application number 201880092213.8, and invention name “Device and method for communication”. Technical Field

[0003] Certain aspects of the present disclosure relate to thermal management of RF front-end components in wireless communication systems operating at millimeter wave (mmWave) frequencies. Background Art

[0004] The fifth generation (5G) or fifth generation plus (5G+) is envisioned to support enhanced vehicle-to-everything (V2X) systems. V2X systems require advanced driving (e.g., fully autonomous driving), extended sensors, and remote control driving for vehicle platooning. In addition, drones are increasingly becoming one of the emerging technologies for remote operation, real-time sensing, and reporting (e.g., video transmission). All of these applications may require high data rates, low latency, and high reliability. For example, vehicle platooning may require periodic data exchange between cars for platooning operations, which requires less than 3 milliseconds (ms) end-to-end latency for cooperation and coordination. For advanced and remote control driving, each vehicle may need data from sensors about its nearby vehicles to achieve safer driving collision avoidance and improved traffic efficiency through coordination. In addition, in order to enhance the perception of the environment, the exchange of raw data from local cameras, light detection and radar (LIDAR), other radars, roadside units, and servers is required. Therefore, autonomous vehicles and drones may require high data rates and extremely low latency and high reliability. As an example, extended sensors and remote control driving require 99.99% and 99.999% reliability, respectively, and it is believed that sensor information sharing between vehicles supporting V2X applications requires 1 Gigabit / second (Gbps) data rate. Similarly, drones require extremely low latency to coordinate with other drones. For the above applications, a communication system that can support the stringent requirements given above is needed.

[0005] There are some standard developments for the above-mentioned system application requirements. These developments include dedicated short-range communications (DSRC). However, DSRC can provide data rates of up to 27 megabits per second (Mbps). In addition, the 6GHz band (e.g., Long Term Evolution (LTE) and other current systems) has become congested and has limited data capacity. As a solution, a wide range of millimeter frequency bands can be considered to achieve high data rate communications. In addition, millimeter wave beamforming provides inherent increased positioning accuracy, inherent physical layer security, and extended coverage. However, high-frequency operation at millimeter wave frequencies will generate considerable excess heat energy due to the operation of the circuits of the radio frequency front end (RFFE). Since the power efficiency of RF components decreases when the heat energy increases, the key issue of millimeter wave systems is the thermal management of RF front-end components. Thus, improved thermal management at millimeter wave frequencies is required. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 A millimeter wave system according to some aspects of the present disclosure is shown.

[0007] Figure 2 A user device according to some aspects of the present disclosure is shown.

[0008] Figure 3 A base station radio head is shown in accordance with some aspects of the present disclosure.

[0009] Figure 4A A radio front end circuit (RFEM) according to some aspects of the present disclosure is shown.

[0010] Figure 4B Another RFEM according to some aspects of the present disclosure is shown.

[0011] Figure 4C An example of a system for generating a multi-carrier baseband signal for transmission according to some aspects of the present disclosure is shown.

[0012] Figure 5 A multi-protocol baseband processor according to some aspects of the present disclosure is shown.

[0013] Fig. 6A A periodic radio frame structure in accordance with some aspects of the present disclosure is shown.

[0014] Figure 6B A periodic radio frame structure using frequency division duplexing (FDD) according to some aspects of the present disclosure is shown.

[0015] Figure 6C A periodic radio frame structure in accordance with some aspects of the present disclosure is shown.

[0016] Fig. 7AA constellation design for a single carrier modulation scheme (called Binary Phase Shift Keying BPSK) containing two points is shown in accordance with some aspects of the present disclosure.

[0017] Figure 7B A constellation design for a single carrier modulation scheme called Quadrature Phase Shift Keying (QPSK) containing 4 points is shown in accordance with some aspects of the present disclosure.

[0018] Figure 7C A constellation design for a single carrier modulation scheme (called quadrature amplitude modulation) containing 16 points in accordance with some aspects of the present disclosure is shown.

[0019] Fig. 8A and Figure 8B Examples of alternative constellation designs for single carrier modulation schemes that may be transmitted and received in accordance with some aspects of the present disclosure are shown.

[0020] Fig. 9 An antenna array system with an intelligent radio frequency front end (RFFE) selection sequence to distribute heat across the antenna array is shown in accordance with some aspects of the present disclosure.

[0021] Fig. 9A is a schematic diagram of hardware configured to measure temperature at one or more locations within each radio frequency integrated circuit (RFIC) according to some aspects of the present disclosure.

[0022] Fig.10 A uniform linear antenna array with ten antenna elements is shown.

[0023] Fig. 10A Subarray selection and codebook antenna thinning according to some aspects of the present disclosure are shown.

[0024] Fig.11 An example of TX / RX selection of thermal density according to some aspects of the present disclosure is shown.

[0025] Fig.12 A comparison of array patterns of antenna arrays using the disclosed thermal mitigation and sub-array type TX / RX chain selection according to some aspects of the present disclosure is shown. Fig.13 A comparison of the sidelobe level (SLL) with a simulated antenna array operation according to the present disclosure and the SLL of a simple sub-antenna array type operation according to some aspects of the present disclosure is shown.

[0026] Fig.14 A comparison of antenna array gain as a function of azimuth when operating all antennas according to aspects of the present disclosure and when operating the antenna array according to the disclosed thermal mitigation is shown.

[0027] Fig.15is a flow chart illustrating a method according to some aspects of the present disclosure.

[0028] Fig.16 is a block diagram of an exemplary machine according to some aspects of the present disclosure, on which any one or more of the techniques or methods discussed herein may be performed, or in which the devices discussed herein may be combined or used. DETAILED DESCRIPTION

[0029] The following description and accompanying drawings fully illustrate specific aspects of the present disclosure, enabling those skilled in the art to practice these aspects. Other aspects may incorporate structural changes, logical changes, electrical changes, process changes, and other changes. Portions and features of some aspects of the present disclosure may be included in portions and features of other aspects, or replace portions and features of other aspects. The aspects of the present disclosure set forth in the claims cover all available equivalents in these claims.

[0030] The millimeter wave frequency range in which the disclosed system is intended to operate is formally defined as spanning a frequency range of about 30 GHz to about 300 GHz, and in practice currently covers several discrete licensed and unlicensed bands.

[0031] The only unlicensed millimeter wave band currently available is around 60 GHz. Licensed bands may include 28 GHz, 39 GHz, 73 GHz, and 120 GHz. The availability of these bands and the specific frequency range of each band varies with regulatory jurisdiction, and in some cases (especially for licensed band operation) there is still a lot of uncertainty in the regulations of some countries. Challenges associated with millimeter wave-based cellular communications include limited range, the directivity of antennas at that range, signal loss caused by using ordinary cables instead of traces, and challenges in integrating multiple antennas for beamforming. These challenges are addressed as discussed below and may include the use of polarization innovations, the use of traces and other lines to avoid signal loss, and improving the ability to be used for beamforming.

[0032] Figure 1 A millimeter wave system 100 is shown. The system includes two components: a baseband circuit 101 and one or more RFEMs 102. The RFEMs are connected to the baseband circuit by a single coaxial cable 130, which provides a modulated intermediate frequency (IF) signal, a DC power supply, a clock signal, and a control signal. Applications of millimeter wave technology may include, for example, WiGig and future 5G, but millimeter wave technology may be applicable to a variety of telecommunication systems. Millimeter wave technology may be particularly attractive for short-range telecommunication systems. WiGig devices operate in the unlicensed 60 GHz band, while 5G millimeter waves are expected to initially operate in the licensed 28 GHz and 39 GHz bands. Figure 11 shows a block diagram of a baseband 101 and RFEM 102 in a millimeter wave system. The baseband 101 is not shown in its entirety, but rather a specific implementation of an analog front end is shown. This includes a transmitter (TX) 131a section with an upconverter 103 to an intermediate frequency (IF) (approximately 10 GHz in the current specific implementation), a receiver (RX) section 131b with a downconversion 105 from IF to baseband, control and multiplexing circuits (including a synthesizer that multiplexes / demultiplexes transmit and receive signals on a single cable 130). In addition, a power tee circuit 109 (which includes discrete components) is included on the baseband circuit board to provide DC power to the RFEM 102. In some aspects of the present disclosure, the combination of the TX section and the RX section may be referred to as a transceiver, to which one or more antennas or antenna arrays of the type described herein may be coupled.

[0033] The RFEM 102 may be a small circuit board that includes multiple printed antennas and one or more RF devices including multiple radio chains, including up / down conversion 104 to millimeter wave frequencies, power combiner / divider 106, programmable phase shift 108, and power amplifier (PA) 110, low noise amplifier (ENA) 112, and control and power management circuits 114a, 114b. This arrangement may be different from Wi-Fi or cellular implementations, which generally have all RF and baseband functions integrated into a single unit and only the antennas are remotely connected via coaxial cables.

[0034] This architectural difference is driven by the extreme power losses at mmWave frequencies in the coaxial cable. These power losses both reduce the transmit power at the antenna and reduce the receive sensitivity. To avoid this problem, the PA 110 and LNA 112 can be moved to the RFEM 102 along with the integrated antenna. In addition, the RFEM 102 can include upconversion / downconversion circuitry 104 so that the IF signal through the coaxial cable 130 can be at a lower frequency. The system context of mmWave 5G is discussed below.

[0035] Figure 2 A user device 200 according to some aspects of the present disclosure is shown. The user device may be a mobile device in some aspects, and may be a user equipment (UE) in some aspects of the present disclosure, as the term is used in the Third Generation Partnership Project (3GPP) and other communication systems. The user device 200 includes an application processor 205, a baseband circuit 210, a radio front end module (RFEM) 215, a memory 220, a connectivity circuit 225, an NFC controller 230, an audio driver 235, a camera driver 240, a touch screen 245, a display driver 250, a sensor 255, a removable memory 260, a power management integrated circuit (PMIC) 265, and a smart battery 270.

[0036] In some aspects of the present disclosure, the application processor 205 may include one or more CPU cores and one or more of the following: cache memory, a low dropout regulator (LDO), an interrupt controller, a serial interface such as SPI, I2C or a general programmable serial interface circuit, a real-time clock (RTC), a timer-counter including an interval timer and a watchdog timer, general purpose IO, a memory card controller such as SD / MMC or similar products, a USB interface, a MIPI interface, and a Joint Test Access Group (JTAG) test access port.

[0037] In some aspects of the present disclosure, baseband circuit 210 may be implemented, for example, as a solder-in substrate that includes one or more integrated circuits, a single packaged integrated circuit soldered to a main circuit board, or a multi-chip module containing two or more integrated circuits.

[0038] Figure 3 A base station radio head 300 is shown in accordance with some aspects of the present disclosure. The base station radio head 300 may include one or more of the following: an application processor 305, baseband circuitry 310, one or more radio front end modules 315, memory 320, power management circuitry 325, power tee circuitry 330, a network controller 335, a network interface connector 340, satellite navigation receiver circuitry 345, and a user interface 350.

[0039] In some aspects of the present disclosure, the application processor 305 may include one or more CPU cores and one or more of the following: cache memory, a low dropout regulator (LDO), an interrupt controller, a serial interface such as SPI, I2C or a general programmable serial interface circuit, a real-time clock (RTC), a timer-counter including an interval timer and a watchdog timer, general purpose IO, a memory card controller such as SD / MMC or similar products, a USB interface, a MIPI interface, and a Joint Test Access Group (JTAG) test access port.

[0040] In some aspects of the disclosure, baseband circuit 310 may be implemented, for example, as a solder-in substrate including one or more integrated circuits, a single packaged integrated circuit soldered to a main circuit board, or a multi-chip module containing two or more integrated circuits.

[0041] In some aspects of the present disclosure, memory 320 may include one or more of the following: volatile memory, including dynamic random access memory (DRAM) and / or synchronous DRAM (SDRAM); and non-volatile memory (NVM), including high-speed electrically erasable memory (commonly referred to as flash memory), phase change random access memory (PRAM), magnetoresistive random access memory (MRAM), and / or three-dimensional cross-point memory. Memory 320 may be implemented as one or more of the following: a solder-in package integrated circuit, a socket memory circuit, and a plug-in memory card.

[0042] In some aspects of the present disclosure, the power management circuit 325 may include one or more of the following: a voltage regulator, a surge protector, a power alarm detection circuit, and one or more backup power sources, such as a battery or capacitor. The power alarm detection circuit may detect one or more of a power failure (brownout) and a surge (overvoltage) condition.

[0043] In some aspects of the disclosure, the power tee circuit 330 may provide power drawn from the network cable to provide both power and data connectivity to the base station radio head 300 using a single cable.

[0044] In some aspects of the present disclosure, network interface circuitry 335 may provide network connectivity using a standard network interface protocol such as Ethernet. Network connectivity may be provided through a physical connection, which is one of an electrical connection (commonly referred to as a copper interconnect), an optical connection, or a wireless connection.

[0045] In some aspects of the present disclosure, satellite navigation receiver circuit 345 may include circuitry for receiving and decoding signals transmitted by one or more navigation satellite constellations, such as Global Positioning System (GPS), Global Navigation Satellite System (GLONASS), Galileo, and / or BeiDou. Receiver 345 may provide data to application processor 305, which may include one or more of position data or time data. Application processor 305 may use the time data to synchronize operations with other radio base stations.

[0046] In some aspects of the present disclosure, the user interface 350 may include one or more buttons, such as a reset button, one or more indicators, such as an LED, and a display screen.

[0047] Figure 4A and Figure 4B A radio front end module (RFEM) according to some aspects of the present disclosure is shown.

[0048] Figure 4AAn aspect of a radio front end module 400 is shown that combines a millimeter wave radio front end module (RFEM) 406 and one or more sub-six gigahertz RFICs 416. In this aspect, the one or more sub-six gigahertz RFICs 416 can be physically separated from the millimeter wave RFEM 406. In some aspects of the present disclosure, the RFEM 406 and the one or more RFICs 416 can be located in the same component. The RFIC 416 can include connections to one or more antennas 421. The RFEM 406 can include multiple antennas 411.

[0049] Figure 4B An alternative aspect of the radio front end module 426 is shown. In this aspect, both the millimeter wave and sub-six gigahertz radio functions can be implemented in the same physical radio front end module 431. The RFEM 431 can incorporate both the millimeter wave antenna 436 and the sub-six gigahertz antenna 441.

[0050] Figure 5 A multi-protocol baseband processor 500 is shown in accordance with some aspects of the present disclosure.

[0051] The baseband processor 500 may include one or more of an IF interface 505, an analog IF subsystem 510, a downconverter and upconverter subsystem 520, a frequency synthesizer 525, an analog baseband subsystem 530, a data converter subsystem 535, and a 5G digital baseband 540. The baseband processor 500 may also include one or more of a 4G digital baseband subsystem 545, a 3G digital baseband subsystem 550, a 2G digital baseband subsystem 555, and a digital IQ interface subsystem 560.

[0052] In some aspects of the present disclosure, the digital baseband subsystem (which may include one or more of 540, 545, 550, and 555) may be coupled to one or more of the CPU subsystem 570, the audio subsystem 575, and the interface subsystem 580 via an interconnect subsystem 565. The interconnect subsystem 565 may include one or more buses and / or one or more network-on-chip (NOC) structures.

[0053] Figure 4C An example of a system for generating a multi-carrier baseband signal for transmission according to some aspects of the present disclosure is shown. In one aspect, data 430 may be input to an encoder 432 to generate encoded data 435. Encoder 432 may include a combination of one or more of error detection, error correction, rate matching, and interleaving. Encoder 432 may also include a scrambling step. In one aspect, encoded data 435 may be input to a modulation mapper 405 to generate complex-valued modulation symbols 440. The modulation mapper may map a group containing one or more binary digits selected from the encoded data 435 to a complex-valued modulation symbol according to one or more mapping tables.

[0054] In one aspect, the complex-valued modulation symbols 440 may be input to the layer mapper 410 to be mapped to one or more layer-mapped modulation symbol streams 445. By denoting the stream of modulation symbols 440 as d(i), where i represents a sequence index, and denoting one or more streams of layer-mapped symbols as x(k)(i), where k represents a stream index and i represents a sequence index, the layer mapping function for a single layer may be represented as:

[0055] x (0) (i) = d(i) (1)

[0056] And the layer mapping of the two layers can be expressed as:

[0057] x (0) (i) = d(2i) (2)

[0058] x (i) (i) = d(2i+1) (3)

[0059] Layer mappings with more than two layers can be represented similarly.

[0060] In one aspect, one or more streams of layer mapped symbols 445 may be input to a precoder 415, which generates one or more streams of precoded symbols 450. By representing the one or more streams of layer mapped symbols as a batch of vectors:

[0061] [x (0) (i)...x (v-1) (i)] T (4)

[0062] Where i represents the range from 0 to The output is represented as a batch of vectors:

[0063] [z (0) (i)...z (P-1) (i)] T (5)

[0064] Where i represents the range from 0 to The precoding operation can be configured to include one of direct mapping using a single antenna port, transmit diversity using space-time block coding or spatial multiplexing.

[0065] In one aspect, each stream of precoded symbols 450 / 450A may be input to a resource mapper 420 / 420A, which generates a stream of resource mapped symbols 455 / 455A. The resource mapper 450 / 450A may map the precoded symbols to frequency domain subcarriers and time domain symbols according to a mapping, which may include contiguous block mapping according to a mapping code, random mapping, or sparse mapping.

[0066] In one aspect, the resource mapping symbols 455 / 455A may be input to a multi-carrier generator 425 / 425A, which generates time-domain baseband symbols 460 / 460A. The multi-carrier generator may generate the time-domain symbols using, for example, an inverse discrete Fourier transform (DFT), typically implemented as an inverse fast Fourier transform (FFT), or a filter bank including one or more filters.

[0067] In one aspect, when resource mapping symbol 455 is represented as S k (i), where k is the subcarrier index and i is the symbol number index, the time domain complex baseband symbol x(t) can be expressed as:

[0068] x(t)=∑ k s k (i)p T (tT sym )exp[j2πf k (tT sym -τ k )] (6)

[0069] Where pr(t) is the prototype filter function, T sym is the start time of the symbol period, k is the subcarrier relative time offset, and f k is the frequency of subcarrier k. The prototype function pr(t) may be, for example, a rectangular time domain pulse, a Gaussian time domain pulse or any other suitable function.

[0070] Fig. 6A , Figure 6B and Figure 6C Frame formats that may be used in various aspects are shown.

[0071] Fig. 6A A periodic radio frame structure 600 that can be used in various aspects is shown. The radio frame structure 600 has a predetermined duration and repeats in a periodic manner at a repetition interval equal to the predetermined duration. The radio frame 600 is divided into two or more subframes 605. In one aspect, the subframes can have predetermined durations that can be unequal. In an alternative aspect, the subframes can have a duration that is dynamically determined and varies between subsequent repetitions of the radio frame 600.

[0072] Figure 6B One aspect of a periodic radio frame structure using frequency division duplexing (FDD) is shown. In one aspect of FDD, a downlink radio frame structure 610 is transmitted by a base station to one or more mobile devices, and an uplink radio frame structure 620 is transmitted by a combination of one or more mobile devices to a base station.

[0073] Fig. 7A , Figure 7B and Figure 7C An example of a constellation design for a single carrier modulation scheme that may be transmitted or received in accordance with one aspect is shown.

[0074] Constellation points 7XX (where XX indicates a distinct number) are shown on orthogonal in-phase and quadrature (IQ) axes, each representing the amplitude of a sinusoid at the carrier frequency and separated in phase from one another by 90 degrees.

[0075] Fig. 7A The constellation including two points 700A and 720A is called binary phase shift keying (BPSK). Figure 7B A constellation containing four points (two of which are listed as 720B and 700B) is called quadrature phase shift keying (QPSK). Figure 7C A constellation comprising 16 points 700 is referred to as quadrature amplitude modulation (QAM) with 16 points (16QAM or QAM 16). Higher order modulation constellations comprising, for example, 64, 256 or 1024 points may be similarly constructed.

[0076] exist Fig. 7A , Figure 7B and Figure 7C In the constellation depicted in , binary codes 720A, 720B, and 720C are assigned to points 700A, 700B, and 700C of the constellation using a scheme such that nearest neighbor points (i.e., pairs of points separated from each other by a minimum Euclidean distance) have assigned binary codes 720A, 720B, 720C that differ by only one binary digit. Figure 7C In the example, the point assigned code 1000 has the codes 1001, 0000, 1100 and 1010 assigned to its nearest neighbors, each of which differs from 1000 by only one bit.

[0077] Fig. 8A and Figure 8B Examples of alternative constellation designs for single carrier modulation schemes that may be transmitted and received in accordance with aspects of the present disclosure are shown.

[0078] Next generation communication systems may utilize large antenna arrays for millimeter wave communications. Due to the small wavelength, a large amount of RFFE will be packed into a very small area to have the beamforming gain required to compensate for the high path loss. However, a key issue for millimeter wave systems is the thermal management (sometimes called thermal mitigation) of RFFE components. In general, the power efficiency of RFFE components decreases with the operating frequency, which will generate a lot of excess energy, and the performance of these components depends on their temperature. Generally, a heat sink is used to transfer heat out of the RFFE. However, when considering the small size of a millimeter wave RFFE, i) the performance of thermal mitigation with an appropriate form factor may not be enough to keep the RFFE operating at an optimal temperature, and ii) the distribution of heat within the RFEM may not be uniform.

[0079] A previous solution to the thermal distribution problem is core switching. With core switching, the RFIC can be powered off for a short duration. In other words, in standard core switching, a subset of antennas or RFICs is in a transmission active state and the subset changes over time. However, the frames sent during this duration have a significantly degraded beam, for example, the beamwidth will be wider, the main lobe gain will be slightly smaller, and the sidelobe levels can be significantly worse. The core switching approach is particularly poor for wide beams, which can be heavily utilized during the beam refinement phase (BRP) and sector scanning because the pseudo-omni codewords are very sensitive to which elements / boxes / RFICs are active. This is because the elements / boxes / RFICs typically cover different angular targets, which are different from the case of using extremely narrow beams. On the other hand, the disclosed subject matter focuses on identifying multiple codebook codewords that turn off selected RFFEs but keep other RFFEs active, thereby obtaining results that are close to and in some aspects even exceed the beam quality (according to the above metrics) compared to having all antenna elements activated. Specifically, the system can cycle (or iterate) through good alternatives for all activated elements in a manner that reduces the duty cycle on a per array block or per array element basis (depending on the limitations of the RFIC) in order to reduce spatial hot spots in the RFIC. The terms RFIC and RFFE may be used herein to refer to the same element or component. Compared to the beamforming codebook, the codebook mentioned above can be considered an RFFE sparse codebook.

[0080] The disclosed subject matter responds to real-time thermal measurements to select a codeword that will provide the most desired cooling for the current hotspot location. In short, an algorithmic method is disclosed for designing a codebook that reduces the total number of active RFFEs used at one time while reducing the sidelobe level of the array pattern. The designed codebook is then used to turn off subsets of RFFEs over time without affecting the performance of the existing beamforming codebook. The following discussion Fig. 9An exemplary RFFE selection scheme is shown in . The algorithm of the created TX / RX chain selection scheme reduces the spatial thermal density, where the term "Tx / RX chain" is understood to mean the complete path through the transmitter and transmit / receive antennas and finally through the receiver. This also enables a low-power mmWave system by disconnecting the entire TX / RX chain including the power amplifier (PA), low noise amplifier (ENA), phase shifters and other active components. This enables a small form factor RFFE design. In some aspects of the present disclosure, it is possible to remove the heat sink completely.

[0081] In the disclosed subject matter, the codeword that most closely approximates optimal in replicating the full-element codeword beam performance for a very specific beam is determined by assembling a set of antenna thinning codewords that allow each block (or element) to be idle for a configurable duration. This means determining different sets of codewords for a given beam, which results in an adaptive or flexible ability to turn the thinning up or down, thereby reducing the duty cycle of a hot spot. In other words, the method responds to real-time thermal measurements to select the codeword that will provide nearly or substantially optimal cooling for the current hot spot location.

[0082] In addition, previous solutions do not have stable beamforming because they experience different effective channels when switching the codewords of the codebook. However, it is desirable to maintain a fixed beam pattern in order to seamlessly switch the codewords of the codebook. This desired result is achieved by the disclosed codeword switching and RFIC rotation, which is actually transparent from the receiver perspective. Further, the previous solution cannot guarantee the desired beam pattern in terms of sidelobe level, beamwidth, beam gain and related parameters after disconnecting the RFIC subgroup. However, the switching interval for performing the disclosed codewords is slower than the standard core switching, thus keeping the communication channel almost fixed from the receiver perspective, which is desirable. Finally, the previous solution does not respond to real-time thermal measurements to select the codeword that will provide the best cooling for the current hot spot location.

[0083] As yet another advantage, the disclosed antenna simple switching improves beamforming through a specific binary optimization method that is adapted to obtain a specific beam with reduced side lobes and desired beam gain, thereby providing stable beam pattern forming with high diversity or near maximum diversity.

[0084] Fig. 9 An antenna array system is shown according to some aspects of the present disclosure, which has an intelligent RFFE selection sequence to distribute heat or heat density across the antenna array. Fig. 9 900 represents k iterations (or selections) of switching the RFFE on and off by a codeword, where k=1, ..., K. Fig. 9, K is 3. At 901, 903, and 905, the clear squares represent RFFEs that are turned on, and the cross-hatched squares represent RFFEs that are turned off by codewords. At 901, i.e., at selection 1 in the sequence of 1, ..., k, ..., K, the cross-hatched squares represent RFFEs that are found to need thermal management (sometimes called thermal mitigation) by real-time thermal measurements when selection 1 and are turned off by codewords, the codewords being generated by the algorithm discussed below. At 903, i.e., at selection k in the sequence of 1, ..., k, ..., K, the cross-hatched squares represent RFFEs that are found to need thermal management by real-time thermal measurements when selection k and are turned off by the algorithm. At 905, i.e., at selection K in the sequence of 1, ..., k, ..., K, the cross-hatched squares represent RFFEs that are found to need thermal management by real-time thermal measurements when selection k and are turned off by the algorithm. This shows that the RFFE shutdowns are sequenced by codeword iterations based on real-time thermal measurements in the RFFEs.

[0085] Fig. 9A906 is a schematic diagram of hardware according to some aspects of the present disclosure, which is configured to physically measure the temperature at one or more locations within each RFIC. The thermal measurement implementation described below may be a physical part of the wireless mobile communication device itself. A modem 907 may be coupled to multiple RFICs. According to some aspects of the present disclosure, the modem 907 is coupled to RFIC1 909 by line 908, to RFIC2 911 by line 910, and to RFICn 913 by line 912, wherein lines 908, 910, and 912 are coupled to a control communication interface between the modem 907 and the RFICs. In the disclosed specific implementation, the baseband modem 907 inquires about the current temperature from one or more RFICs 909, 911, 913, ..., which may be accomplished by a command sent through the control communication interface (which in some aspects may be via a Manchester coded 300MHz control channel). With respect to the RFIC 909, the first step may be to have the modem 907 send a temperature read command (which may be referred to as "TEMP") either to a single RFIC 909 or, in some aspects, broadcast to all RFICs 909, 911, ..., 913. The RFIC to which the TEMP command is sent may sample the temperature using a thermal sensor at one or more locations within the RFIC (such as at each feed of the antenna array coupled to the RFIC in some aspects), thereby utilizing the integrated circuit of the RFIC as indicated at 909A, 911A, ..., 913A, which shows "each feed of the antenna array". However, the thermal sensors may be located elsewhere in the RFIC as desired. In some aspects, the thermal sensors are distributed within the RFIC of the RFFE per block of antenna elements, and control communications are sent from the baseband modem to the corresponding RFIC to interrogate the temperature as discussed above.

[0086] In a second step, the RFIC returns the current temperature to the baseband modem 907. At step 3, the firmware running on the modem 907 can utilize the current temperature measurements at various special locations within the RFIC. According to some aspects of the present disclosure, this can be implemented for each subsystem of the antenna array. These temperature measurements are used to determine the weights fed to the algorithm that selects the desired duty cycle of the circuits feeding each antenna element in the array, as discussed above in this paragraph.

[0087] The key concept is that each candidate codeword has a specific duty cycle distribution based on elements not used for a beam or used at a lower power level. The goal is to select / schedule the one or more codewords such that a low duty cycle of a particular element corresponds to a measured high temperature of the circuitry that supports those elements. More specifically, algorithms implemented on a modem or other processing element utilize temperature measurements received from different spatial regions within one or more RFICs (such as each LNA / PA / phase shifter / switch feeding each element or sub-array within an array). The goal of these algorithms is to identify and reduce hotspots within one or more RFICs feeding an antenna array. These temperature measurements are used to determine whether a particular part of the system is operating at a high enough temperature level that can affect performance. The desired duty cycle of operation for each spatial region can be determined based on these temperature measurements, where hotter regions are identified to operate at a lower duty cycle until the operating temperature in these regions is reduced to the desired temperature. By reducing these hotspots using this information about the current hotspots and the desired duty cycle, codewords of a sparse codebook can be selected that together achieve the desired operating duty cycle in the identified hot spatial regions. This is achieved because each interchangeable codeword provides a similar beam but different sets of elements are idle or operating at a lower transmit power. Thus, the scheduling of the appropriate codewords effectively reduces the operating duty cycle of the circuitry within the identified hotspots to meet the desired duty cycle and causes the heat within these hotspots to be reduced.

[0088] Fig.10 A uniform linear antenna array 1000 with twenty antenna elements is shown. The algorithm controlling Fig. 9 the switching is explained with respect to Fig.10 the shown uniform linear antenna array and can then be extended to a rectangular antenna array. An indicator vector for TX / RX chain selection can be represented by d i = [d0, d1, ···, dN], where N is the total number of RFFEs such that di ∈ {0, 1}, i = 0, ···, N. Here, in {0, 1}, 0 means the TX / RX chain is off and 1 means the TX / RX chain is on. Next, the problem can be formulated such that M of the N RFFEs are selected (where M < N), thereby reducing the sidelobes while maintaining a similar beamforming gain 20log 10M. Therefore, 1∞-norm minimization can be used to reduce the sidelobe level. This means minimizing the maximum value of each element of the vector F(θ)Ad in the following formula (7), where each element of the vector F(θ)Ad represents the array gain for the sidelobe, and minimizing the maximum value means minimizing the sidelobe. This has been discussed in the following paper: C.Rusu, N.Gonzalez-Prelcic and RWHeath, "Antenna array thinning for antenna selection in millimeter wave MIMO systems", 2016IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), Shanghai, 2016, pp. 3416-3420. Therefore, the problem can be formulated as follows:

[0089]

[0090] Where F(θ)Ad is a vector and the function shown is a diagonal matrix of antenna patterns f(θk), k=l, . . . , K, and minimization is to minimize the elements of the vector, which means minimizing the side lobes. K×N The vector group corresponding to the azimuth angle located at the side lobe is given as follows:

[0091]

[0092] in

[0093] d a is the distance between radiator elements of a uniform linear antenna array expressed in wavelength λ;

[0094] a is the array response vector of arrival or departure angle θk, and T is the transpose operator.

[0095] The matrix A is defined over the antenna pattern F(θ) to keep the maximum sidelobe level at a minimum.

[0096] The above is a binary l∞-norm minimization problem, which means that it is non-convex and NP-hard. Therefore, a weighted convex relaxation technique can be used, as shown, for example, in the following papers: C. Rusu, N. Gonzalez-Prelcic and RW Heath cited above or B. Fuchs, "Synthesis of Sparse Arrays With Focused or Shaped Beam pattern via Sequential Convex Optimizations", IEEE Transactions on Antennas and Propagation, Vol. 60, No. 7, pp. 3499-3503, July 2012. These two papers are two examples of many papers. In this disclosure, we will use a technique of adding a penalty to the objective function so that the norm of the binary variable bi is maximized.

[0097]

[0098] where bi is the relaxation of di. In the original problem formulation in (7), d i is 0 or 1. In formula (9), we replace di with bi so that bi can be a real number between 0 and 1, that is, bi∈[0,1]. In formula (9), the second term is for b i A weighted optimization of to achieve relaxation terms for faster convergence. The weights are given by the vector w.

[0099] A method of determining a set of TX / RX chain selection vectors (i.e., codebook) such that a desired thermal density is achieved will now be described. The designed codebook may take into account expected or real-time measured thermal accumulation throughout the antenna array as discussed above in order to statistically bias which codewords are selected, thereby improving the system's ability to adapt to hot spots in the system and thus minimizing peak spatial thermal density during operation while maximizing beam quality. In terms of expected thermal accumulation, if the thermal accumulation is predictable, the codebook may be designed offline.

[0100] Codebook design for TX / RX chain selection

[0101] One step of the method is the determination of a selection of a number M of activated TX / RX chains from the N TX / RX chains, where M TX / RX chains are needed to maintain a desired beamforming gain of 10log 10(M). Since operating a smaller number of antennas means less radiated power (assuming each TX chain has its own power amplifier) ​​and less combined gain of the RX chains, the total number of activated TX / RX chains should be selected so that the communication link has sufficient beamforming gain, i.e., the desired beamforming gain ≤ 20log 10M. Disconnecting NM TX / RX chains will save approximately (NM) / N% power at the RFIC. In addition, M should be selected considering the tradeoffs between signal-to-noise ratio (SNR) limit, spatial thermal overload and interference risk, meaning victim and / or attacker. The SNR limit has a 20log 10 An upper bound on M. The purpose of the proposed algorithm is to reduce the thermal density at the antenna array. The thermal density reduction is achieved by disconnecting some RFFE elements. Therefore, reducing thermal overload may reduce the SNR gain due to the reduction in beamforming gain, but the disclosed codeword-based antenna thinning keeps the SNR reduction to a minimum, which can be considered as a side benefit of the optimization. Suboptimal RFFE turning off antenna elements may increase beamwidth and sidelobe levels. This may increase interference. On the other hand, the proposed solution (RFFE switching optimized by codeword-based antenna thinning) minimizes the increase in beamwidth and sidelobe levels, and minimizes the increase in interference, thus representing a significant improvement over other approaches. In addition, disconnecting the RFFE will cause a loss in beamforming gain. However, the optimization minimizes the beamforming gain loss compared to other solutions (such as modular antenna switching), as shown in the simulation results discussed below.

[0102] The second step in creating the codebook is to iteratively design the codewords for the codebook. Since the codebook is designed so that good thermal density is achieved, some of the TX / RX chains that must be disconnected can be preselected, and then the remaining TX / RX chains that can be turned off to have substantially the lowest sidelobe levels are found, and this results in the required number of TX / RX chains to be disconnected. Subarray type RFFE selection is a special case of the proposed algorithm, so that M TX / RX chains can be preselected from N TX / RX chains on a modular basis (using half or quarter of the array at a time, etc.). This special case is to turn off a contiguous subgroup of RFFEs, such as Fig. 10A shown. Fig. 10ABoth subarray selection and codebook antenna thinning are shown in accordance with some aspects of the present disclosure. Subarray selection is not optimized and is represented relative to array 1001. Array element groups 1001A, 1001B, 1001C, and 1001D are 4×4 element subarrays in an 8×8 array. Subarray selection can be used as a method of thermal mitigation without any optimization, where the subarray can be switched, for example, from 1001A to 1001B, 1001C, and then to 1001D. Since antenna arrays are designed in a modular manner, i.e., small antenna arrays are snapped together to have a larger antenna array, disconnecting subarrays can be considered a thermal mitigation solution, but this is suboptimal and results in sidelobe growth and beamwidth growth, both of which are undesirable. In codebook based antenna thinning, antenna elements are switched on and off according to a codebook, where in antenna array 1003, antenna array elements to be switched off are selected according to a codeword, which produces an on / off pattern, portions of which can be seen in 1003A, 1003B, 1003C, and 1003D. The disclosed codebook based antenna thinning produces a binary (on / off) optimization or improvement compared to subarray selection, where the beamwidth remains unchanged and the sidelobes are lower. The algorithm for codebook design will be discussed below.

[0103] Algorithm-1 (Select which RFFEs among M RFFEs to disconnect for a codeword in the codebook.)

[0104] Input: w (0) =lN, where lN is a vector of size N of 1, M is the number of RFFEs that need to be disconnected, d is set to a binary vector with pre-selected elements of zero, the iteration number K, Z = {1,...,N}.

[0105] Set Z←Z\m, where m is the index of the zero element in the d vector, which is an auxiliary vector that records the indices of the connected and disconnected RFFEs.

[0106] b←d

[0107] while|Z|>M

[0108] For K iterations

[0109] ·Solution

[0110]

[0111] Update w t <-1—b i , i∈Z

[0112] End

[0113] ·

[0114] ·Z<-Z\m,d m =0.

[0115] End

[0116] A codebook that achieves good heat density can then be designed by the second algorithm:

[0117] Algorithm-2

[0118] enter:

[0119] The basic TX / RX chain set for thermal distribution is turned off when thermal measurements are made, D = Φ.

[0120] while, where D is the codebook

[0121]

[0122] Choose some index i such that

[0123] Solution Algorithm-1

[0124] ·

[0125] End

[0126] Fig.11 An example 1100 of TX / RX selection for thermal density according to some aspects of the present disclosure is shown. The performance of a rectangular array of N=8×8 or 64 elements will be discussed. Consider M=32. This means about 50% less power consumption at the RF front end. The codebook is given by the symbol D. For Fig.11 For example, at 1100, two codewords 1102, 1104 are seen to have been generated for the TX / RX chain selection. In one aspect of the disclosure, to cover all codewords, 9 codewords are generated so that each RFFE can be disconnected at least once. This means that some antenna elements can be disconnected more than once to obtain the desired beam pattern for all codewords. Codeword-based antenna thinning is simulated in this case, and when compared to a sub-array type TX / RX chain selection where only half of the (8×4) or 32 array is activated to have the same number of activated elements (i.e., 32), codeword-based thermal mitigation actually increases the main lobe by about 0.35 dB, while reducing the side lobes by 7.1 dB.

[0127] Fig.12 At 1200, a comparison of a simulated array pattern of an antenna array using the disclosed thermal mitigation and an array pattern of a sub-array type TX / RX chain selection is shown according to some aspects of the present disclosure. Fig.12In FIG. 1 , only half of the (4×8) array is activated to have the same number of activated elements, i.e., 32. Curve 1310 is the array gain with the disclosed codeword-based thermal mitigation, and curve 1320 shows the array gain with subarray-type thermal mitigation. Comparison of these two curves shows that there is essentially no loss in main beam power, which is 20log 10 M=20log 10 32 = 30.1030 dB. This means that switching the RFFE elements according to the disclosed thermal mitigation method will maintain the existing active channels to keep the beam pattern as similar as possible when the antenna element is switched from the "on" condition to the "off" condition.

[0128] Fig.13 A comparison of the sidelobe level (SLL) of the operation with the simulated antenna array according to the present disclosure and the operation with the simple sub-antenna array type TX / RX selection according to some aspects of the present disclosure is shown at 1300. Curve 1410 represents the sidelobe level when the disclosed thermal mitigation method is used, and curve 1420 represents the sidelobe level when the sub-array based TX / RX chain selection is used. It can be observed that the sidelobe level (SLL) of the proposed codebook operation is significantly lower than the sub-array type TX / RX selection. Fig.13 The horizontal axis in the Fig.12 Example 1200 of TX / RX selection to generate the index of the codeword.

[0129] Fig.14 At 1500, a comparison of antenna array gain as a function of azimuth when operating all antennas according to some aspects of the present disclosure is shown, compared to the antenna array gain when operating the antenna array using the disclosed thermal mitigation methods. Fig.14 This was accomplished using simulations. Curve 1510 shows the array gain when using the disclosed thermal mitigation, and curve 1520 shows the array actor when all antennas are used. Observation shows that the difference in maximum beamforming gain is approximately 6 dB when all TX / RX chains are used for beamforming versus when half the antennas are used. The SLL is approximately 1 dB lower than when all TX / RX chains are used. In this case, the beamwidth is similar, but the sidelobes are reduced. The comparison is a two-dimensional plot. A simulated three-dimensional plot shows the same comparison.

[0130] Fig.151 is a flow chart illustrating a method 1500 according to some aspects of the present disclosure. At 1501, the method starts with N TX / RX chains. At 1503, a number M is selected, where M is less than N. M is selected to meet a desired beamforming gain of 10logl0(M). M is also selected to meet SNR constraints and reduce sidelobe levels. M is also selected to have a desired thermal reduction and sufficient power consumption reduction. At 1505, TX / RX chains to be disconnected from the M TX / RX chains are preselected based on system constraints. At 1507, some of the TX / RX chains are preselected so that the subarrays are disconnected. At 1509, a matrix A is defined to reduce sidelobes. At 1511, an iteration number K is defined for a desired beam pattern. At 1513, a codebook is algorithmically designed based on Algorithms 1 and 2 above by considering antenna patterns that achieve better performance based on sidelobe reduction.

[0131] Fig.16 A block diagram of an exemplary machine 1600 according to some aspects of the present disclosure is shown, on which any one or more techniques or methods discussed herein may be performed. In alternative aspects, the machine 1600 may operate as a standalone device or may be connected (e.g., networked) to other machines. In a networked deployment, the machine 1600 may operate as a server machine, a client machine, or both in a server-client network environment. In one example, the machine 1600 may act as a peer machine in a peer-to-peer (P2P) (or other distributed) network environment. The machine 1600 may be a UE, an eNodeB, an AP, a STA, a personal computer (PC), a tablet PC, a set-top box (STB), a personal digital assistant (PDA), a mobile phone, a smart phone, a web device, a network router, a switch or a bridge, or any machine capable of (in order or otherwise) executing instructions that specify actions to be taken by the machine. Further, while a single machine is illustrated, the term "machine" shall also be taken to include any collection of machines that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein (such as cloud computing, Software as a Service (SaaS), and other computer cluster configurations).

[0132] Examples as described herein may include a logical component or multiple components, circuits, modules or mechanisms, or may operate on a logical component or multiple components, circuits, modules or mechanisms. A circuit is a tangible entity (e.g., hardware) that can perform a specified operation and may be configured or arranged in a certain manner. In one example, a circuit may be arranged in a specified manner (e.g., internally or relative to an external entity such as other circuits), and in some respects may be arranged as a module. In one example, all or part of one or more computer systems (e.g., independent computer systems, client computer systems, or server computer systems) or one or more hardware processors may be configured by firmware or software (e.g., instructions, application parts, or applications) to operate to perform a specified operation of the module. In one example, the software may reside on a machine-readable medium. In one example, the software, when executed by the underlying hardware of the module, causes the hardware to perform the specified operation.

[0133] Thus, the term "circuitry" should be understood to encompass a tangible entity, i.e., an entity that is physically constructed, specifically configured (e.g., hardwired), or temporarily (e.g., transiently) configured (e.g., programmed) to operate in a specified manner or to perform part or all of any of the operations described herein. Considering an example where a module or circuit is temporarily configured, each module or circuit need not be instantiated at any one time. For example, if the circuit includes a general-purpose hardware processor configured using software, the general-purpose hardware processor may be configured into corresponding different modules or different circuits at different times. The software may configure the hardware processor accordingly, for example, to constitute a particular module at one instance in time and to constitute a different module at a different instance in time.

[0134] The machine (e.g., a computer system) may include a hardware processor 1602 (e.g., a central processing unit (CPU), a graphics processing unit (GPU), a hardware processor core, or any combination thereof), a main memory 1604, and a static memory 1606, some or all of which may communicate with each other via an interconnection link (e.g., a bus) 1608. The machine 1600 may also include a display unit 1610, an alphanumeric input device 1612 (e.g., a keyboard), and a user interface (UI) navigation device 1614 (e.g., a mouse). In one example, the display unit 1610, the input device 1612, and the UI navigation device 1614 may be a touch screen display. The machine 1600 may additionally include a storage device (e.g., a drive unit) 1616, a signal generating device 1618 (e.g., a speaker), a network interface device 1620, and one or more sensors, such as a global positioning system (GPS) sensor, a compass, an accelerometer, or other sensors. The machine 1600 may include an output controller 1628, such as a serial (e.g., Universal Serial Bus (USB)) connection, a parallel connection, other wired or wireless (e.g., infrared (IR), near field communication (NFC), etc.) connection to communicate with or control one or more peripheral devices (e.g., a printer, a card reader, etc.).

[0135] The storage device 1616 may include a machine-readable medium 1622 on which is stored one or more sets of data structures or instructions 1624 (e.g., software) embodied or utilized by any one or more of the techniques or functionality described herein. The instructions 1624 may also reside, completely or at least partially, within the main memory 1604, within the static memory 1606, or within the hardware processor 1602 during execution of the instructions 1624 by the machine. In one example, one or any combination of the hardware processor 1602, the main memory 1604, the static memory 1606, or the storage device 1616 may constitute a machine-readable medium.

[0136] Although the machine-readable medium 1622 is illustrated as a single medium, the term “machine-readable medium” may include a single medium or multiple media (eg, a centralized or distributed database, and / or associated caches and servers) configured to store one or more instructions 1624 .

[0137] The term "machine-readable medium" may include any medium capable of storing, encoding, or carrying instructions for execution by a machine and causing the machine to perform any one or more of the techniques of the present disclosure, or any medium capable of storing, encoding, or carrying data structures used by or associated with such instructions. Non-limiting examples of machine-readable media may include solid-state memory, and optical and magnetic media. Specific examples of machine-readable media may include: non-volatile memory, such as semiconductor memory devices (e.g., electrically programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM)) and flash memory devices; disks, such as internal hard disks and removable disks; magneto-optical disks; random access memory (RAM); and CD-ROM and DVD-ROM disks. In some examples, the machine-readable medium may include non-transitory machine-readable media. In some examples, the machine-readable medium may include a machine-readable medium that is not a transient propagation signal.

[0138] The instructions 1624 may also be transmitted or received in a communication network 1626 via the network interface device 1620 using a transmission medium, the transmission or reception utilizing any of a plurality of transmission protocols (e.g., frame relay, Internet Protocol (IP), transmission control protocol (TCP), user datagram protocol (UDP), hypertext transfer protocol (HTTP), etc.). Exemplary communication networks may include a local area network (LAN), a wide area network (WAN), a packet data network (e.g., the Internet), a mobile telephone network (e.g., a cellular network), a plain old telephone (POTS) network, and a wireless data network (e.g., the Institute of Electrical and Electronics Engineers (IEEE) 802.11 series known as The IEEE 802.16 series of standards is known as ), IEEE802.15.4 series standards, Long Term Evolution (LTE) series standards, Universal Mobile Telecommunications System (UMTS) series standards, peer-to-peer (P2P) networks, etc. In one example, the network interface device 1620 may include one or more physical jacks (e.g., Ethernet, coaxial cable, or telephone jacks) or one or more antennas to connect to the communication network 1626. In one example, the network interface device 1620 may include multiple antennas to use at least one of single-input multiple-output (SIMO), multiple-input multiple-output (MIMO), or multiple-input single-output (MISO) technology for wireless communication. In some examples, the network interface device 1620 may use multi-user MIMO technology for wireless communication. The term "transmission medium" should be deemed to include any intangible medium that can store, encode, or carry instructions for machine execution, and includes digital or analog communication signals or other intangible media to facilitate communication of such software.

[0139] Example

[0140] Embodiment 1 is a device for a user equipment (UE), comprising: N transmit / receive (TX / RX) chains, each TX / RX chain comprising an RFFE, each RFFE comprising one or more thermal sensors configured to measure heat in the RFFE; an antenna array coupled to the plurality of TX / RX chains; and a codebook comprising a plurality of codewords configured to respond to real-time thermal measurements from the thermal sensors in each TX / RX chain to shut down a selected TX / RX chain to reduce heat density at the antenna array.

[0141] In Embodiment 2, the subject matter of Embodiment 1 optionally includes wherein a magnitude of a sidelobe level of the antenna array decreases after shutting down a selected TX / RX chain.

[0142] In Embodiment 3, the subject matter of any one or more of Embodiments 1-2 optionally includes wherein the beamforming gain of the antenna array after shutting down the selected TX / RX chain is substantially the same as the beamforming gain of the antenna array before shutting down the selected TX / RX chain.

[0143] In embodiment 4, the subject matter of any one or more of embodiments 1-3 optionally includes that the antenna array beamforming gain after shutting down the selected TX / RX chain is less than a certain dB before shutting down the selected TX / RX chain, 4 lacks, parent: 5. The apparatus of embodiment 1, wherein the communication channel received by the antenna array is a communication channel after shutting down the selected TX / RX chain that is substantially the same as the communication channel before shutting down the selected TX / RX chain.

[0144] In Embodiment 5, the subject matter of any one or more of Embodiments 1-4 optionally includes wherein a channel state indicator (CSI) value received by a receiver of the device after shutting down a selected TX / RX chain is substantially the same as a CSI value received by the receiver of the device before shutting down the selected TX / RX chain.

[0145] In Embodiment 6, the subject matter of any one or more of Embodiments 1-5 optionally includes wherein information including real-time thermal measurements is sent to a modem and used to shut down selected TX / RX chains.

[0146] In Example 7, the subject matter of any one or more of Examples 1-6 optionally includes (M).

[0147] Embodiment 8 is an evolved Node B (eNB) apparatus comprising: N transmit / receive (TX / RX) chains, each TX / RX chain comprising an RFFE, each RFFE comprising one or more thermal sensors configured to measure heat in the RFFE; an antenna array coupled to the plurality of TX / RX chains; and a codebook comprising a plurality of codewords configured to respond to real-time thermal measurements from the thermal sensors in each TX / RX chain to shut down a selected TX / RX chain to reduce heat density at the antenna array.

[0148] In Embodiment 9, the subject matter of Embodiment 8 optionally includes wherein a magnitude of a sidelobe level of the antenna array decreases after shutting down a selected TX / RX chain.

[0149] In Embodiment 10, the subject matter of any one or more of Embodiments 8-9 optionally includes wherein the beamforming gain of the antenna array after shutting down the selected TX / RX chain is substantially the same as the beamforming gain of the antenna array before shutting down the selected TX / RX chain.

[0150] In Embodiment 11, the subject matter of any one or more of Embodiments 8-10 optionally includes the antenna array beamforming gain after shutting down the selected TX / RX chain being less by a certain dB than before shutting down the selected TX / RX chain.

[0151] In Embodiment 12, the subject matter of any one or more of Embodiments 8-11 optionally includes a communication channel after shutting down the selected TX / RX chain wherein the communication channel received by the antenna array is substantially the same as the communication channel before shutting down the selected TX / RX chain.

[0152] In Embodiment 13, the subject matter of any one or more of Embodiments 8-12 optionally includes wherein a CSI value received by a receiver of the eNB after shutting down a selected TX / RX chain is substantially the same as a CSI value received by the receiver of the eNB before shutting down the selected TX / RX chain.

[0153] In Embodiment 14, the subject matter of any one or more of Embodiments 8-13 optionally includes wherein information including real-time thermal measurements is sent to a modem and used to shut down selected TX / RX chains.

[0154] In Example 15, the subject matter of any one or more of Examples 8-14 optionally includes (M).

[0155] Embodiment 16 is a method of designing a codebook to reduce thermal density in a system by shutting down selected TX / RX chains, the system comprising N TX / RX chains coupled to an antenna array, wherein each TX / RX chain comprises an RFFE, the method comprising: selecting M number of activated TX / RX chains from the N TX / RX chains, wherein the M TX / RX chains give a desired system beamforming gain of 10log10(M), a desired system signal-to-noise ratio, and antenna pattern sidelobe level reduction; and designing the iterative codewords of the codebook by the solutions of the following two algorithms: Algorithm 1 represented by the following: Input: w(l7 missing, parent: 0) = 1N, M, d is a binary vector with pre-selected elements of zero, iteration number K, Z = {l,...,N}.

[0156] Embodiment 17 is one or more computer-readable hardware storage devices having a set of instructions embedded therein, which, when executed by one or more processors controlling N TX / RX chains, each TX / RX chain includes an RFFE coupled to an antenna array, each RFFE includes one or more thermal sensors, and the one or more thermal sensors are configured to measure heat in the RFFE, and the operations include: monitoring real-time thermal measurement values ​​by the one or more thermal sensors in each RFFE; and shutting down a predetermined number of N TX / RX chains by using a codebook including multiple codewords, the multiple codewords being configured to iteratively execute in response to the monitored real-time thermal measurement values ​​in each TX / RX chain to reduce the heat density at the antenna array coupled to the N TX / RX chains.

[0157] In Embodiment 18, the subject matter of Embodiment 17 optionally includes wherein a magnitude of a sidelobe level of the antenna array decreases after shutting down a selected TX / RX chain.

[0158] In Embodiment 19, the subject matter of any one or more of Embodiments 17-18 optionally includes wherein the antenna array beamforming gain after shutting down the selected TX / RX chain is substantially the same as the antenna array beamforming gain before shutting down the selected TX / RX chain.

[0159] In Embodiment 20, the subject matter of any one or more of Embodiments 17-19 optionally includes the antenna array beamforming gain after shutting down the selected TX / RX chain being less by a certain dB than before shutting down the selected TX / RX chain.

[0160] In Embodiment 21, the subject matter of any one or more of Embodiments 17-20 optionally includes a communication channel after shutting down the selected TX / RX chain wherein the communication channel received by the antenna array is substantially the same as the communication channel before shutting down the selected TX / RX chain.

[0161] In Example 22, the subject matter of any one or more of Examples 17-21 optionally includes a CSI value where the CSI value received by the receiver of the device after turning off the selected TX / RX chain is substantially the same as the CSI value received by the receiver of the device before turning off the selected TX / RX chain.

[0162] In Example 23, the subject matter of any one or more of Examples 17-22 optionally includes information including real-time thermal measurement values being sent to a modem and used to turn off the selected TX / RX chain.

[0163] In Example 24, the subject matter of any one or more of Examples 17-23 optionally includes a codeword being configured to turn off the selected TX / RX chain while keeping M RFFEs on, where M < N and the desired beamforming gain is 10log10(M).

[0164] In Example 25, the subject matter may include any part or combination of any multi-parts of any one or more of Examples 1 to 24, or may optionally be combined with any part or combination of any multi-parts of any one or more of Examples 1 to 24 to include such a subject matter that may include a device for performing any one or more of the functions of Examples 1 to 24, or a machine-readable medium containing instructions that, when executed by a machine, cause the machine to perform any one or more of the functions of Examples 1 to 24.

[0165] The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings illustrate, by way of example, specific aspects in which the disclosed subject matter may be practiced. These aspects are also referred to herein as “examples”. If there is an inconsistent usage between this document and those documents incorporated by reference, the usage in the incorporated reference documents shall be considered as a supplement to the usage in this document; for irreconcilable inconsistencies, the usage in this document shall prevail.

[0166] In this document, the terms "a" or "an" are used (as is common in patent documents) to include one or more than one, independent of any other instance or use of "at least one" or "one or more". In this document, unless otherwise stated, the term "or" is used to refer to non-exclusivity or such that "A or B" includes "A but not B", "B but not A", and "A and B". In the appended claims, the terms "including" and "in which" are used as the plain English equivalents of the corresponding terms "comprising" and "wherein". Similarly, in the following claims, the terms "including" and "comprising" are open-ended, that is, a system, device, article, or process that includes elements other than those listed after the term in the claim is still considered to fall within the scope of the claim. In addition, in the following claims, the terms "first", "second", and "third", etc. are used only as labels and are not intended to impose numerical requirements on their objects.

[0167] The above description is intended to be illustrative, not restrictive. For example, the above examples (one or more aspects thereof) may be used in combination with each other. Other aspects may be used, such as by a person of ordinary skill in the art after reviewing the above description. In addition, in the above specific embodiments, various features may be combined to simplify the present disclosure. This should not be interpreted as an expectation that unclaimed disclosed features are essential to any claim. Rather, the subject matter of the invention may exist in the form of less than all the features of a particular disclosed aspect. Therefore, the following claims are hereby incorporated into the specific embodiments, wherein each claim exists independently as a separate aspect. The scope of the subject matter disclosed in the present disclosure should be determined with reference to the appended claims and the full scope of the equivalents of the claims.

[0168] The abstract of the specification is provided to let the reader understand the essence and gist of the technical disclosure. It is considered that the abstract of the specification will not be used to limit or interpret the scope or meaning of the claims. The following claims are hereby incorporated into the detailed description, wherein each claim stands independently as a separate aspect.

Claims

1. A wireless communication device, comprising: Antenna arrays; a plurality of radio frequency front end (RFFE) circuit elements coupled to the antenna array at corresponding respective transmit and / or receive TX / RX chains; a first thermal sensor coupled to a first RFFE circuit element of the plurality of RFFE circuit elements; a second thermal sensor coupled to a second RFFE circuit element of the plurality of RFFE circuit elements; as well as One or more processors configured to: receiving respective temperature measurements from the first thermal sensor and the second thermal sensor, and The collective power of the respective TX / RX chains is adjusted based on the respective temperature measurements.

2. The wireless communication device of claim 1, wherein the one or more processors are further configured to adjust the collective power of the corresponding TX / RX chains according to a codebook.

3. The wireless communication device of claim 2, wherein the one or more processors are further configured to enable and disable selected ones of the corresponding TX / RX chains based on one or more codewords from the codebook to adjust the collective power of the corresponding TX / RX chains. 4 . The wireless communication device of claim 3 , wherein the one or more processors are further configured to select the one or more codewords based on the corresponding temperature measurements.

5. The wireless communication device of claim 3, wherein the one or more codewords are generated such that a maximum level of one or more side lobes for an antenna pattern of the antenna array is minimized.

6. The wireless communication device of claim 1, wherein the corresponding temperature measurements are real-time temperature measurements.

7. The wireless communication device of claim 1 , wherein the respective temperature measurements identify a thermal spatial region in the antenna array, wherein the one or more processors are configured to adjust the collective power of the respective TX / RX chains to reduce heat density in the thermal spatial region.

8. A wireless communication device according to claim 1, wherein after the collective power of the corresponding TX / RX chains has been adjusted, the beamforming gain of the antenna array does not change by more than a specified value relative to the beamforming gain of the antenna array before the collective power of the corresponding TX / RX chains is adjusted.

9. A baseband circuit comprising: an interface configured to be coupled to a radio front end (RFE) module, the RFE module comprising a plurality of transmit and / or receive TX / RX receive chains coupled to an antenna array; as well as one or more processors coupled to the interface and configured to: receiving respective temperature measurements from two or more of the plurality of TX / RX chains, wherein each respective temperature measurement corresponds to a different respective TX / RX chain, and A collective power of the plurality of TX / RX chains is adjusted based on the respective temperature measurements.

10. The baseband circuit of claim 9, wherein the one or more processors are further configured to adjust the collective power of the corresponding TX / RX chains according to a codebook.

11. The baseband circuit of claim 10, wherein the one or more processors are further configured to enable and disable selected ones of the corresponding TX / RX chains according to one or more codewords from the codebook to adjust the collective power of the corresponding TX / RX chains.

12. The baseband circuit of claim 11, wherein the one or more processors are further configured to select the one or more codewords based on the corresponding temperature measurements.

13. The baseband circuit of claim 11, wherein the one or more codewords are generated such that a maximum level of one or more side lobes for an antenna pattern of the antenna array is minimized.

14. The baseband circuit of claim 9, wherein the corresponding temperature measurements are real-time temperature measurements.

15. The baseband circuit of claim 9, wherein the respective temperature measurements identify a thermal spatial region in the antenna array, wherein the one or more processors are configured to adjust the collective power of the respective TX / RX chains to reduce heat density in the thermal spatial region.

16. A non-transitory memory element storing program instructions executable by one or more processors to: monitoring temperature measurements in two or more of a plurality of transmit and / or receive TX / RX chains coupled to the antenna array; identifying a spatial region of the antenna array that meets or exceeds a temperature threshold based on the temperature measurements; as well as The collective power of the plurality of TX / RX chains is adjusted to reduce heat density in the identified spatial region.

17. The non-transitory memory element of claim 16, wherein the program instructions are further executable by the one or more processors to: The collective power of the plurality of TX / RX chains is adjusted according to a codebook.

18. The non-transitory memory element of claim 17, wherein the program instructions are further executable by the one or more processors to: Selected ones of the plurality of TX / RX chains are enabled and disabled according to one or more codewords from the codebook to adjust the collective power of the plurality of TX / RX chains.

19. The non-transitory memory element of claim 18, wherein the program instructions are further executable by the one or more processors to: The one or more codewords are selected based on the temperature measurement.

20. The non-transitory memory element of claim 16, wherein the temperature measurements are real-time temperature measurements.

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