Patent Publication Number: US-2016233580-A1

Title: Method and apparatus to control the gain of a millimeter wave phased array system

Description:
TECHNOLOGICAL FIELD 
     This disclosure is generally related to wireless communications. More particularly, the disclosure is related to millimeter wave phased array communication systems. 
     BACKGROUND 
     Millimeter wave (MMW) transmissions travel by line-of-sight, and may be blocked by building walls or attenuated by foliage. The high free space loss and atmospheric absorption may sometimes limit propagation to a few kilometers. Thus MMW are useful for densely packed communications networks such as personal area networks that improve spectrum utilization through frequency reuse. 
     Due to the relatively high attenuation of MMW transmissions, multiple-antenna arrays may be used to increase the accuracy and gain of received transmissions. Some of the antennas arrays may be multiple-in, multiple-out (MIMO) antenna arrays or phased array systems. 
     SUMMARY 
     One aspect of the disclosure provides a phased array system, comprising a first antenna element and a second antenna element. A first transceiver can have a first power amplifier and be operably coupled to the first antenna element. A second transceiver can have a second power amplifier and be operably coupled to the second antenna element. A first power detector can be coupled to the first antenna element and provide a first detector output. A second power detector can be coupled to the second antenna element and provide a second detector output. A gain controller can be operably coupled to the first transceiver, the first power detector, the second transceiver and the second power detector. The gain controller can disable one or more of the first transceiver and the second transceiver based on the first detector output and the second detector output. 
     Another aspect of the disclosure provides a method for wireless communication in a phased array system. The phased array system can have at least a first antenna element operably coupled to a first transceiver having a first power amplifier and a second antenna element operably coupled to a second transceiver having a second power amplifier. The method may comprise enabling the first transceiver and the second transceiver. The method may further comprise detecting a detector output from at least one of the first power detector and the second power detector. The method may further comprise disabling one or more of the first transceiver and the second transceiver based on the detector output while maintaining operation of the antenna array in a predetermined range of maximum efficiency. 
     Another aspect of the disclosure provides an apparatus for wireless communication in a phased array system. The phased array system can have a first antenna element and a second antenna element operably coupled to a respective first transceiver and a second transceiver of a plurality of transceivers. The apparatus may comprise a gain controlling means for enabling each of the first transceiver and the second transceiver. The gain controlling means can further disable one or more of the first transceiver and the second transceiver based on a detector output while maintaining maximum efficiency of the enabled transceivers. The apparatus may further comprise a first detecting means for providing a first detector output to the gain controlling means. The first detecting means can be operably coupled to the first antenna. The apparatus may further comprise a second detecting means for providing a second detector output to the gain controlling means. The second detecting means can be operably coupled to the second antenna. 
     Another aspect of the disclosure provides a phased array system comprising a plurality of antenna elements. Each antenna element of the plurality of antenna elements can be coupled to a respective transceiver of a plurality of transceivers. Each transceiver can have at least one power amplifier with an adjustable gain. A power detector can be coupled to each antenna of the plurality of antenna elements and configured to provide a detector output. The detector output can be configured to indicate at least an output power level and a reflected energy level at a respective antenna element of the plurality of antenna elements. A gain controller can be operably coupled to each of transceiver of the plurality of transceivers and to each power detector. The gain controller can receive the detector output. The gain controller can further adjust the adjustable gain of one or more selected power amplifiers to achieve a selected transmit power level for the phased array system based on the detector output. The gain controller can further enable or disable one or more of the transceivers of the plurality of transceivers based on the detector output. 
     Other features and advantages of the present invention should be apparent from the following description which illustrates, by way of example, aspects of the invention. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The details of the present disclosure, both as to its structure and operation, may be gleaned in part by study of the accompanying drawings, in which like reference numerals refer to like parts, and in which: 
         FIG. 1  is a plot diagram illustrating an example of total transmission efficiency versus effective isotropically radiated power (EIRP) of an exemplary phased array system; 
         FIG. 2  is a functional block diagram of an exemplary embodiment of a phased array system according to the present disclosure; 
         FIG. 3  is a plot diagram illustrating an example of total transmission efficiency of the exemplary phased array system of  FIG. 2 ; 
         FIG. 4A  is a flowchart depicting an exemplary method for selectively disabling transceivers to maintain optimum efficiency in a phased array system according to the present disclosure; and 
         FIG. 4B  is a flowchart depicting another embodiment for selectively disabling transceivers to maintain optimum efficiency in a phased array system. 
     
    
    
     DETAILED DESCRIPTION 
     The detailed description set forth below, in connection with the accompanying drawings, is 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. The detailed description includes specific details for the purpose of providing a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in simplified form for brevity of description. 
     Millimeter wave (mmW or MMW) transmissions are generally deemed to fall within the 30 to 300 gigahertz frequencies of the electromagnetic spectrum. This range may also be referred to as the Extremely High Frequency (EHF) range. EHF is the International Telecommunications Union (ITU) designation for the band of radio frequencies, above which electromagnetic radiation is considered to be far infrared light, also referred to as terahertz radiation. Radio waves within the MMW band have wavelengths from approximately one to ten millimeters, giving it the name millimeter band or millimeter wave. 
     Due to the transmission frequency and wavelength of MMW radiation, MMW systems may be susceptible to atmospheric absorption and attenuation. MMW transmissions may be impeded or attenuated by structures (e.g., walls and buildings) or other natural phenomena such as foliage or precipitation. As such, some MMW systems may use antenna arrays such as the phased arrays to increase the gain of a wireless system and compensate for the extra propagation path losses. Thus, MMW systems may be configured to adjust the gains (G) of both receiver and transmitter to boost the strength of an otherwise attenuated signal. 
     Phased array antennas may comprise a plurality of antenna elements that use the phase and magnitude of transmitted energy to “steer” transmitted radiation, creating multiple beams or transmission “lobes.” Transmitted energy may be steered or directed by exploiting constructive or destructive interference resulting from variations in phase and magnitude in the electromagnetic energy across the plane of transmitting phased array elements. 
     MMW systems may be configured with programmable gains implemented in multiple internal components such as low-noise amplifiers (LNA), power amplifiers (PA), mixers, and intermediate frequency (IF)/baseband (BB) amplifiers. The total radiated energy from a phased array antenna may then be controlled by adjusting the gain of the various PAs, LNAs, or similar components. However, reduction of transmitter power by adjusting the gain of the amplifying components can, at some level, reduce the components&#39; efficiency resulting in suboptimum performance and power loss. For example, as the gain of a PA of one or more antenna elements is reduced to decrease total transmitted power, the PA bias shifts towards class-A amplifier operation. This may also shift the load impedance away from the optimum, matched impedance. 
       FIG. 1  is a plot diagram illustrating an example of total transmission efficiency versus effective isotropically radiated power (EIRP) of an exemplary phased array system, according to the disclosure. The vertical (y) axis is total transmission efficiency and the horizontal (x) axis is EIRP. EIRP may be referred in terms of decibels, specifically dBm, or the power ratio in decibels of the measured power referenced to one milliwatt (mW). EIRP may alternatively be referred to in terms of dBW, which is referenced to one watt (W). 
     As described herein, EIRP may generally refer to the amount of power that a theoretical isotropic antenna (which evenly distributes power in all directions) would emit to produce the peak power density observed in the direction of maximum antenna gain. In certain embodiments, EIRP may take into account losses occurring within certain transmission components (e.g., the LNAs, PAs, etc.) and connectors and includes the gain of an antenna element or entire antenna array. The EIRP is often stated in terms of decibels (dBm, dBW) in excess of a reference power emitted by an isotropic transmitter with equivalent signal strength. EIRP can be useful for comparisons between emitters of different types or those having different sizes or forms. 
     The exemplary phased array system described by the plot  100  assumes a fixed number of enabled phased array antenna elements. For example, the phased array that may produce the plot  100  of  FIG. 1  may have eight antenna elements that are always enabled during a given transmission. 
     As shown, the plot  100  indicates that transmission efficiency of the system increases as the linearity of the resulting system EIRP decreases. A maximum linear EIRP  110  may be referred to as the maximum EIRP at which the system meets the linearity requirements. If a given system is required to transmit at a power level below the maximum linear EIRP  100 , the gain of one or more of the PAs of the phased array elements may be reduced, reducing the overall power level of the entire phased array. In some embodiments this can result in a reduction in overall system efficiency because the system may consume more power than necessary for the given output power. 
       FIG. 2  is a functional block diagram of an embodiment of a phased array system. As shown, a phased array system  200  may include a plurality of antenna elements (elements)  202   a - 202   n  (collectively, elements  202 ). Each of the antenna elements  202  in general may each be considered an individual antenna. 
     The antenna elements  202  are labeled  202   a,    202   n  indicating any number of antenna elements  202  may be present, for example, the antenna elements 1:N, as shown. As shown, a series of three dots similar to an ellipsis indicate the repeating portions of the elements of  FIG. 2 . This is shown in several places in  FIG. 2 . In some embodiments, each of the antenna elements  202  may operably connected, via various components as described below, to a transmitter input and a receiver output. In this embodiment each of the antenna elements  202  is configured to transmit and receive MMW transmissions, as disclosed herein. 
     The phased array system  200  may include a transmitter input (Tx in)  204 . In some embodiments, the Tx in  204  may represent a transmitter input from a signal source from certain electronics, such as other elements of a radio (besides the phased array system) in a mobile electronic device. The transmitter input may be radio frequency (RF) transmissions or other similar inputs for transmission to a receiver. 
     The Tx in  204  is operably coupled to a transmitter (Tx) upconverter  206 . The Tx upconverter  206  may include several subcomponents configured to convert an input to the frequency band in which the MMW phase array system  200  is operating. 
     The Tx up converter  206  may be operably connected to at least one transmitter variable gain amplifier (TxVGA)  208  configured to amplify the up converted signal as required. The TxVGA  208  may be operably coupled to a power splitter  210 . The power splitter  210  may be configured to split the incoming signal from the TxVGA  208  into n portions for transmission to each of the antenna elements  202   a - 202   n.  In some embodiments, the power splitter  210  may split the signal into equivalent portions for transmission by each of the antenna elements  202 . Each portion of the split signal may then be provided to a Tx phase shifter  212   a - 212   n,  as shown. The Tx phase shifters  212   a - 212   n  (collectively, Tx phase shifters  212 ) may be configured to shift the phase of the signal they receive as required to produce the desired transmission direction (e.g., for phased array beam forming) of the phased array system  200 . The Tx phase shifters  212  may be operably coupled to a power amplifier, such as multistage power amplifier (PA)  220   a - 220   n  (collectively, PAs  220 ). The PAs  220  may include one or more stages of power amplifiers having a programmable gain, indicated by the arrow. The gain may be programmed by a controller, as described below. Each of the PAs  220  may be operably connected to the corresponding antenna elements  202   a - 202   n.  Accordingly, the PAs  220  may directly affect the power level of the signal transmitted from the antenna element  202 . 
     In some embodiments, the connection between the PAs  220  and the elements  202  is a switched connection (as shown), allowing each of the antenna elements  202  to switch between transmitting a signal and receiving a signal. 
     In an embodiment, each of the antenna elements  202  may be operably connected to a multistage low noise amplifier (LNA)  230   a - 230   n  (collectively, LNAs  230 ) via the same switched connection. Due to relatively high attenuation of MMW transmissions, each of the LNA  230   s  may include one or more stages of low noise amplification, providing a usable signal to the rest of the array system  200 . The LNAs  230  may be operably connected to a Rx phase shifter  232   a - 232   n  (collectively, Rx phase shifters  232 ) to incoming signals received at each of the antenna elements  202 . Each of the Rx phase shifters  232  may further provide the phase shifted signal to a power combiner  234  which may further be operably connected to a RxVGA  236 . The RxVGA  236  may adjust the gain of the combined received signal for further transmission to an Rx downconverter  238 . The Rx downconverter  238  may be further operably coupled to a receiver output (Rx out)  205 . The Rx out  205  may be analogous to an RF output that may be subject to further analysis or transform as required by a given mobile device or other applicable system. 
     In an embodiment, the phased array system  200  further includes a gain controller  240 . The gain controller  240  may be operably coupled to each of the PAs  220  and configured to control the variable gain of the PAs  220 . Such an adjustment may be beneficial in maintaining an optimum or matched impedance with the antenna elements  202 . The gain controller  240  may also be configured to receive certain inputs from a power detectors  242   a - 242   n  (collectively power detectors  242 ). Each of the power detectors  242  may be operably coupled to a respective antenna element  202  in order to provide an estimation of transmit power levels or a received power levels across the array of antenna elements  202 . The power detectors  242  may be configured to measure both incident RF energy and reflected RF energy at the antenna elements  202 . For example, the reflected RF energy may be that energy that was transmitted at the antenna element  202   a  and reflected back to the antenna element  202   a.  The reflected energy may be indicative of antenna obstruction or blockage, such as blockage by a hand as in case of a mobile wireless device, (e.g., a UE). 
     The gain controller  240  may also be configured to receive a received signal strength indication (RSSI)  244 . The RSSI  244  may be an overall or average signal strength indication received at the array system  200 . The RSSI  244  input to the gain controller  240  may further provide a reference value for each of the power level measurements at each antenna element  202 . Such a reference value may be further useful to the array system  200  for the determination of received signal or transmitted signal direction. In an embodiment, the RSSI  244  may be provided by the power detectors  242 . 
     In some embodiments, the power detectors  242  may be capacitively coupled to each antenna element  202  and configured to measure the transmit power per channel (e.g., in each antenna element  202 ). Power detectors  242  may also be based on coupled transmission lines to further measure both incident and reflected waves (energy) for the given antenna element  202  to detect blockage of the antenna by a hand or other object. 
     Such an embodiment may control the gain of individual antenna elements  202  based on measurements of individual antenna element  202  transmit power and/or by monitoring the RSSI  244 . The gain controller  240  may further vary the antenna transmit power by adjusting the power amplifier  220  gain individually on a per element basis (e.g., per antenna element  202 ), without individually disabling any antenna elements  202 . Such an embodiment may further vary the gain of the LNAs  230  in order to adjust the power level of the received signal appropriately. 
     However, as noted above in  FIG. 1 , reducing transmitter power (e.g., the transmit power levels of the antenna elements  202 ) by adjusting or reducing the PA  220  gain reduces the overall efficiency of the array system  200  because the output power of the PA  220  decreases faster than its power consumption. In some embodiments, the output power of the PA  220  is proportional to the square of the bias current, while the power consumption is proportional to the bias current. This situation may arise, for example, when the phased array system  200  is implemented in user equipment (UE) such as phone or tablet. In such an embodiment, the user&#39;s hand may block a portion of the array system  200 . Accordingly, the MMW phased array system  200  system may adjust for transmission blockage of part or all of the antenna elements  202  in the array system  200 . However, transmission or attempted reception of signals through such blocked antennas may result in a significant waste of power. 
     The gain controller  240  may be further operably coupled to a plurality of transceiver blocks (transceivers)  250   a - 250   n  (collectively, transceivers  250 ). The transceivers  250 , as described herein, may refer to the collective functions of at least each pair of the Tx phase shifters  212  and the PAs  220 , and each pair of Rx phase shifters  232  and LNAs  230 . The transceivers  250  are shown in dashed lines and may refer to at least the functions of the four elements described. For example, the transceiver  250   a refers to the functions of the Tx phase shifter  212   a,  the PA  220   a,  the LNA  230   a,  and the Rx phase shifter  232   a.  In an embodiment, the transceivers  250  as disclosed herein may also refer to the waveform-producing/transmitting and receiving components, for example the PAs  220  and the LNAs  230 . In another embodiment, the transceivers  250  may refer to a transmitter/receiver pair configured to transmit and receive energy from the antenna elements  202 . In another embodiment, the transceivers  250  may refer to those components that draw power from the array system  200  during a transmit or receive operation from a particular antenna element  202  (e.g., the antenna element  202   a ); for example when the transceiver  250   a is disabled, no power is transmitted from the antenna element  202   a  power to the transceiver is minimized. 
     In operation, the gain controller  240  may further be configured to remove or otherwise deactivate one or more respective transceivers  250  as required. Such operation may be similar to an ON-OFF power switch. This may serve to optimize the efficiency and transmission power level of the entire array system  200  by selectively removing power from selected transceivers  250 . 
     In an embodiment, and as described in connection with  FIG. 3  below, in the presence of a blocked antenna element  202   a,  the gain controller  240  may receive power information regarding power levels from the power detectors  242 . The information may indicate to the gain controller  240  that one or more of the antenna elements  202  is blocked or otherwise obstructed. In response, the gain controller may disable certain antenna elements  202 , corresponding to certain blocked antennas (e.g., antenna elements  202 ) for example. Accordingly, the gain controller  240  removes power from the associated transceiver block  250   a.  As a result, no power may be delivered to the antenna element  202   a.  This may serve to reduce power consumption of the entire system (e.g., the array system  200 ) as noted below. In certain embodiments, the gain controller  240  may concurrently adjust (e.g., raise or lower) the gain of one or more of the other PAs  220  in response to the blocked antenna element(s)  202  in order to maintain maximum efficiency of the system  200 . 
       FIG. 3  is a plot diagram illustrating an example of total transmission efficiency of the exemplary phased array system of  FIG. 2 . As shown, a plot diagram  300  depicts EIRP along the x-axis with total transmission (Tx) efficiency along the y-axis. Similar to the plot diagram  100  ( FIG. 1 ), the units of EIRP may be referred to in terms of dBm/dBW. 
     The diagram  300  includes a dotted line  302  that is similar to the diagram  100 , indicating the efficiency of a phased array system (e.g., the array system  200 ) incorporating adjustable gain at the PAs  220 . The dotted line  302  increases from a minimum EIRP having a minimum efficiency at a point  304 , to a maximum linear EIRP  306  (shown in a dashed line) at the right of the diagram  300 . 
     The diagram  300  also depicts a line  320  that depicts the transmission efficiency of the array system  200  ( FIG. 2 ) operated according to an embodiment of the present disclosure. The line  320  begins at a point  322  on the left of the curve and increases EIRP to maximum total efficiency at a point  324 . The point  324  may have the same or similar efficiency as the point  304 , but at a lower maximum EIRP. 
     According to such an embodiment, by disabling certain antenna elements  202 , no signal is received and/or transmitted from those antenna elements  202 . By disabling selected the receiver/transmitter pair (e.g., the element  202   a ), the total gain of the array system  200  in a certain spatial direction is varied as 20*log(N enabled ), where N enabled  is the number of enabled antennas in the array system  200 . The gain is varied such that the power amplifiers  220  of the enabled channels (e.g., the antenna elements  202 ) may continue operating in a maximum-gain setting, with maximum efficiency. 
     For example, if the array system  200  has eight antenna elements  202 , enabling or disabling individual antenna elements  202  may allow the gain controller  240  to set the overall gain of the array system  200  to G+0 dB, G+6 dB, G+9.5 dB, G+12 dB, G+14 dB, G+15.6 dB, G+16.9 dB, and G+18 dB incrementally for each of one through eight enabled elements  202 , where G is an offset gain. This may be possible without affecting the bias or the output power of enabled power amplifiers  220 . When N enabled  approaches 1, the variation in gain when enabling or disabling the antenna elements  202  becomes large, such as the drop depicted at the point  330 . Accordingly, the gain controller  240  may adjust the gain of the enabled PAs  220  to an intermediate power (EIRP) level and associated efficiency. 
     Viewed from the right to the left,  FIG. 3  depicts such a logarithmic increase in the effect of disabling a single transceiver  250 . At the point  304 , the system  200  is operating at the maximum efficiency and the maximum EIRP. In an embodiment, this may indicate that all of the transceivers  250   a - n  (and corresponding PAs  220 ) are all functioning at maximum gain. In the event one or more of the antenna elements  202  is blocked, one or more of the power detectors  242  may indicate to the gain controller that there is a partial obstruction of one or more of the antenna elements  202 . The gain controller  240  may then command a deactivation of the one or more transceivers without affecting the system efficiency, until EIRP is reduced to a point  314 , below which deactivating (e.g., turning off) additional transceivers results in larger-than-desired EIRP steps. At the point  314 , if incremental reductions in EIRP in smaller increments than are possible from completely deactivating another transceiver are required, the gain controller  240  may command a decrease in the gain of one or more of the enabled PAs  220   a - n.  The decrease in gain may result in a decrease in EIRP and efficiency toward the point  315 . 
     At the point  315 , the efficiency decreases with the decreased EIRP to a level where the gain controller  240  may disable one of the transceivers  250   a - n.  The gain controller  250  may further simultaneously reset the gains of transceivers  250  that remain enabled to their individual maximum linear value. In an embodiment, when only one of the transceivers  250   a - n  is disabled, and n-1 transceivers  250  remain enabled, the EIRP may be reduced by an EIRP step defined by the value, 20*log(n/(n-1)) dB, which can be smaller than a maximum allowed EIRP step. The EIRP step may describe the reduction in EIRP from the point  314  to the point  315 , for example. Because the step from the point  314  to the point  315  is small, there may be no need to adjust the gains of the PAs  220  of enabled transceivers  250 . 
     The EIRP can be further reduced by deactivating transceivers  250  until the EIRP step value, 20*log(N enabled /(N enabled +1)), becomes larger than a maximum allowed EIRP step (e.g., at the point  314 ), as noted above. In other words, the magnitude of successive EIRP decrements may increase because the ratio of enabled transceivers  250  to total transceivers  250  available becomes smaller. Therefore, additional reduction in EIRP may be achieved by reducing the gain of one or more PAs  220  of the enabled transceivers  250  until EIRP moves toward the point  315 , at which point the gain reduction of enabled transceivers is equal to 20*log(N enabled /(N enabled +1)). Adjusting EIRP below the point  315  can be accomplished by deactivating one more transceivers  250  while simultaneously restoring the gain of the PAs  220  associated with the other enabled transceivers  250  to their maximum linear values, and so on. This may result in an optimum performance of the enabled PAs  220  associated with un-obstructed antenna elements  202 . 
     In an embodiment, each transceiver  250 , and by extension, each antenna element  202  (antenna) of the phased array is configured to be enabled or disabled as determined by the gain controller  240 . The Tx in  204  and the Rx out  205  connected (via the internal connections) to individual antenna elements  202  may effectively be turned ON and OFF (e.g., an ON/OFF switch) as indicated in  FIG. 2 . The gain controller  240  may generate signals to command the transceivers  250  connected to individual antennas elements  202 . 
     Accordingly at lower gain modes of the array system  200  or during partial hand blockage of one or more antenna elements  202 , a significant improvement in transmit and receive efficiency over the system described in connection with  FIG. 1  may be realized when the gain controller  240  is configured to selectively enable/disable the transceiver blocks  250 . The efficiency of the array system  200  as described in  FIG. 3  can increase efficiency at the gain settings Gmax−20 log(N), where N is the number of antennas. 
       FIG. 4A  is a flowchart depicting a method for selectively disabling transceivers to maintain optimum efficiency in a phased array system, according to the disclosure. As shown a method  400  begins at block  410  where the phased array system  200  enables a plurality of the antenna elements  202  in the array. In an embodiment, enabling may refer to applying power to the transceivers  250  associate with the plurality of selectively enabled antenna elements  202 . In another embodiment, the selectively enabled antenna elements  202  may comprise all of the antenna elements  202  in the array  200 . In yet another embodiment, the gain controller  240  may function to enable the antenna elements  202 , as disclosed herein. 
     At block  420 , the gain controller  240  may receive an input from one or more of the power detectors  242  and the RSSI  244 . The input and the RSSI  244  may also be collectively referred to as a detector output. Such an output may be indicative of reflected power at the one or more antenna elements  202 . Accordingly, the detector output may indicate that one or more of the antenna elements  202  may be obstructed or otherwise blocked. In an embodiment continued transmission (e.g., by the associated transceiver  250 ) in the presence of the obstruction may result in wasted power and lower efficiency. 
     At block  430  the gain controller  240  may, in response to the detector output, remove power from the transceiver  250  associated with the affected antenna element(s)  202 . In an embodiment, removing power from the transceiver  250  may refer to turning the transmitter/receiver pair associated with the affected antenna element(s)  202  off As a result, the antenna elements  202  that remain active (e.g., the unblocked antenna elements  202 ) will continue operating at their maximum efficiency as disclosed herein. 
     In some embodiments, the method  400  may be employed to maintain or otherwise achieve a maximum efficiency of the array system  200  by enabling and disabling selected transceivers  250  based on the detector outputs. 
       FIG. 4B  is a flowchart depicting another embodiment for selectively disabling transceivers to maintain optimum efficiency in a phased array system, according to the disclosure. As shown, the method  450  begins with block  460  where a plurality of antenna elements  202  of a phased array system  200  are enabled. In an embodiment, such a plurality may be all of the antenna elements  202  in the system  200 . 
     At block  470 , the gain controller  240  may receive a power detector output (e.g., from the power detector  242 ). The detector output may indicate operation in a state approaching the maximum linear EIRP of the system  200 . In an embodiment, such an output may be result of a comparison between the output power level, the gain of the power amplifiers  220  and the RSSI  244 . The detector output may further indicate a partial or total blockage of one or more antenna elements  202 . At block  480 , the gain controller  240  may adjust the gain of one or more of the power amplifiers  220  associated with the affected transceivers  250 . In an embodiment, the “adjusting” may include an increase or decrease of the gain of the affected power amplifiers  220 . 
     At block  485 , in response to the adjusted gain(s) power amplifiers  220 , the gain controller  240  may receive a detector output (e.g., from the power detector  242 ) indicative of a decrease in efficiency of the adjusted power amplifiers  220  or their associated transceivers  250 , antenna elements  202 , and/or the entire array system  200 . 
     At block  490 , the gain controller  240  may further remove power from the affected transceiver(s)  250  in response to the decreased efficiency of the power amplifiers  220 . In an embodiment, removing the power from the transceivers  250  that are operating below optimum performance may increase the overall transmission efficiency of the entire system  200  and allow the remaining enabled transceivers  250  (e.g., the transceivers  250  that are not affected by the blockage) and the associated power amplifiers  220  to continue to operate at their maximum efficiency. 
     Accordingly, in some embodiments, the gain controller  240  may receive the detector output at block  470  or block  485  and enable or disable the transceivers  250  (and by extension, the power amplifiers  220 ) in order to achieve or otherwise maintain a maximum EIRP of the phased array system  200 . 
     Although embodiments of the disclosure are described above for particular embodiments, many variations of the invention are possible. For example, the numbers of various components may be increased or decreased, modules and steps that determine a supply voltage may be modified to determine a frequency, another system parameter, or a combination of parameters. Additionally, features of the various embodiments may be combined in combinations that differ from those described above. 
     Those of skill will appreciate that the various illustrative blocks described in connection with the embodiments disclosed herein can be implemented in various forms. Some blocks have been described above generally in terms of their functionality. How such functionality is implemented depends upon the design constraints imposed on an overall system. Skilled persons can implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the invention. In addition, the grouping of functions within a block or step is for ease of description. Specific functions or steps can be moved from one block or distributed across to blocks without departing from the present disclosure. 
     The various illustrative logical blocks described in connection with the embodiments disclosed herein, for example, gain controller  240 , can be implemented or performed with a general purpose processor, a digital signal processor (DSP), application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor can be a microprocessor, but in the alternative, the processor can be any processor, controller (e.g., the gain controller  240  as disclosed herein), microcontroller, or state machine. A processor can also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. 
     The steps of a method or algorithm described in connection with the embodiments disclosed herein can be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium. An exemplary storage medium can be coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium can be integral to the processor. The processor and the storage medium can reside in an ASIC. 
     The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles described herein can be applied to other embodiments without departing from the spirit or scope of the present disclosure. Thus, it is to be understood that the description and drawings presented herein represent a presently preferred embodiment of the present disclosure and are therefore representative of the subject matter which is broadly contemplated by the present disclosure. It is further understood that the scope of the present disclosure fully encompasses other embodiments that may become obvious to those skilled in the art and that the scope of the present disclosure is accordingly limited by nothing other than the appended claims.