Patent Publication Number: US-2019199425-A1

Title: Interference reduction from terrestrial base station transmission to fixed satellite service

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/609,457, filed Dec. 22, 2017, the disclosure of which is hereby incorporated herein it its entirety by reference. 
    
    
     BACKGROUND 
     With the increased demand for Broadband Wireless Access (BWA) networks, there is a significant interest in sharing the same radio spectrum for BWA and Fixed Satellite Service (FSS). However, many FSS receivers are located in the same geographical areas as the areas with an increased demand for BWA. Signals received by FSS ground receivers travel long distances from geostationary communication satellites and thus may have weak signal strength upon arrival at the FSS ground receivers. These received FSS signals may be weak and may benefit from significant protection from BWA signals from nearby terrestrial base stations and user equipments (UE) transmitters. Interference from terrestrial base station BWA transmitters to the FSS satellite receivers is thus of concern. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram illustrating a geographical area that is served by Fixed Satellite Service (FSS) satellites and by a Broadband Wireless Access (BWA) network, according to some embodiments of the present inventive concepts. 
         FIG. 2  and  FIG. 3  illustrate FSS and BWA network transmissions, according to some embodiments of the present inventive concepts. 
         FIG. 4A  illustrates adjacent channel power ratio, according to some embodiments of the present inventive concepts. 
         FIG. 4B  and  FIG. 5  illustrate FSS and BWA network transmissions, according to some embodiments of the present inventive concepts. 
         FIG. 6  illustrates communications in a BWA network, according to some embodiments of the present inventive concepts. 
         FIG. 7  is a block diagram of a wireless electronic device, according to some embodiments of the present inventive concepts. 
         FIG. 8  is a block diagram of an example processor and memory that may be used in accordance with embodiments of the present inventive concepts. 
         FIGS. 9 to 17  are flowcharts illustrating operations for reducing interference at a FSS receiver, according to some embodiments of the present inventive concepts. 
     
    
    
     DETAILED DESCRIPTION 
     Example embodiments of the present inventive concepts now will be described with reference to the accompanying drawings. The present inventive concepts may, however, be embodied in a variety of different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present inventive concepts to those skilled in the art. In the drawings, like designations refer to like elements. 
     Satellite downlink transmission of broadcast television occurs in the C-band (3.7 GHz to 4.2 GHz) from Fixed Satellite Service (FSS) satellites while uplink transmission may be between 5.925 to 6.425 GHz. A typical satellite may have multiple C-band transponders, with each transponder having one or more channels occupying a total bandwidth up to 72 MHz. A terrestrial FSS receiver may receive signals from various channels transmitted by some, but not all of the C-band transponders. Although the example embodiment provided herein are in the context of C-band FSS receivers, the techniques described herein may apply to any frequency bands used by FSS satellites and/or FSS receivers, such as Ku-band FSS satellites and/or FSS receivers. A geostationary satellite may be at a distance of more than 22,000 miles from a FSS receiver. Due to the distance traveled by the signals from the C-band satellite transponders, the signal strength may be relatively weak and thus may be susceptible to interference from terrestrial communication networks such as Broadband Wireless Access (BWA) networks. Base stations (BS) and User Equipments (UE) of BWA networks may be in close proximity (i.e. within a few miles) to the FSS receivers. Various embodiments described herein arise from the recognition that terrestrial co-channel use of satellite frequencies may interfere with the satellite signals received at the satellite receive station. MIMO interference reduction techniques are described herein in a real-world environment to reduce interference to FSS receivers. 
     Modern communication systems utilize Orthogonal Frequency Division Modulation (OFDM) and other advanced waveforms to create signals from a base station (BS) targeted to User Equipments (UEs). The base station may enhance the signal to a given UE while reducing the signal strength in other areas not near the given UE, by using directional techniques such as beam forming and/or solutions such as massive multiple-input and multiple-output (MIMO) systems. Channel State information (CSI) may be used to configure MIMO and/or massive MIMO systems. The term “channel state information” (CSI) may be used to refer to channel characteristics between a base station and a UE in a BWA network. The term “satellite channel status” (SCS) may be used to refer to channel characteristics between a satellite and the FSS receiver. 
     In wireless communications, channel state information, may refer to known channel properties of a communication link. This information describes how a signal propagates from the transmitter to the receiver and represents the combined effect of, for example, scattering, fading, and power decay with distance. Techniques such as channel estimation may be used to characterize the aforementioned effects. The CSI makes it possible to adapt transmissions to current channel conditions, which may be used for achieving reliable communication with high data rates in multi-antenna systems. In some cases, the CSI may be measured and/or estimated at the FSS receiver and fed back to the base station transmitter in order to facilitate transmitter adjustments such as channel selection, transmit power, etc. The CSI may be used by a base station or a UE in a BWA network to improve the quality of communication. In other words, signal transmission parameters between BWA network elements such as a base station and a UE may be changed to reduce interference to an FSS receiver&#39;s operation. 
     Depending on the channel state information associated with a given FSS site, a base station may make computations that will use one or more multi-element antennas at the base station to enhance or reduce the radio signal strength directionally. In some embodiments, multiple base stations may coordinate with one another to directionally send signals to UEs. Interference may be mitigated in systems where base stations may be in different locations but still cover similar and/or partially overlapping geographical areas. 
     A Massive MIMO beamforming solution using a feedback loop between monitor stations located near or at the FSS receiver site and/or one or more BWA base stations may reduce interference between FSS signals and BWA signals. Monitor stations may include passive devices, modified UEs, or custom built receivers that listen for and/or receive FSS transmissions and/or BWA network transmissions between UEs and base stations. In some embodiments, a UE of the BWA network may perform the functionality of the monitor station. Monitor stations may be located after the FSS antenna, or if that is not possible, within meters of near or at the FSS receiver (i.e., in close geographic proximity to the FSS receiver). In some embodiments, monitor stations may be configured to listen for and/or receive C-band signals, but may not transmit C-band signals. The monitor stations may facilitate a second feedback loop that detects signals before or after the FSS receiver antenna and provides information about interfering signals that have been seen by the monitor station to the BS controller. This second feedback loop may work in conjunction with the first feedback loop or may work independently from the first feedback loop. The second feedback loop may include a receiver/detector monitor located before or after the FSS antenna, and may be designed to specifically look for unique characteristics of the BS or UE waveform in order to discriminate from the FSS signal, or take advantage of a gap in transmission, blanking interval, or unused spectrum located between multi-carrier transponders in the FSS downlink transmissions. A gap or blanking interval in the downlink transmissions can occur due to the nature of the application or by operator design without significantly affecting the performance of the FSS. C-band signals for FSS may include services such as broadcast television that may have gaps or blanking intervals periodically or aperiodically between segments of data. The monitor stations, may send the CSI or the SCS to the core network directly to one or more of the base stations in order to effect the feedback loop and allow the offending BS to take corrective action. 
     The UE may also contribute to a raised interference level at the FSS site. Monitor stations may monitor base station transmissions or may monitor UE transmissions. In the case of UE caused interference, the UE may not be able to modify antenna patterns, so the feedback loop would need to inform the base station to no longer allocate frequencies falling within the channel receive bandwidth of the FSS receiver to the offending UE. This could include shifting operation between the UE and the base station to an in band channel with FSS or to an out of band channel, if available. 
     Additionally, a terrestrial FSS receiver (i.e., ground station) may provide information to the core network, the base station, or the base station controller regarding polarization, modulation, channel on/off status, and/or antenna pattern information, which may be used by the base station controller to further reduce interference potential. This information may be sent back to the base station controller via monitoring stations via a wired facility and/or on an out-of-band channel. 
     In some embodiments, CSI or SCS may be sent to the core network or to the base station controller from monitor stations during a FSS downlink transmission. Monitor stations may send this information infrequently, such that the disruption to FSS transmissions may occur infrequently, thus causing minor signal interference/degradation. In some embodiments, monitor receivers may send information infrequently, such as when interference that is causing an increase in Bit Error Rate (BER) is detected. FSS receivers may take advantage of Forward Error Correction (FEC) methods to overcome any minor degradation of FSS downlinks. FSS operation may also assign a small portion of the FSS frequency band, such as a FSS sub-band, to enable feedback to the base station controller. The FSS sub-band may be used on a continuous basis to provide a feedback loop for the CSI or SCS to the base station controller and reduce/minimize interference to the FSS receiver from a BWA base station. 
     Communication between UEs and the base station may interfere with the signal received by FSS signals. In some embodiments, in order to mitigate interference from a UE to BS at the FSS receiver, the state information from the UE may be transmitted in guard bands between the downlink channels used by the C-band transponders to communicate with the terrestrial FSS receiver. Use of the guard bands by the UE to transmit state information may significantly reduce interference with the FSS receiver. 
     Various embodiments will now be discussed in further detail with reference to the figures. 
       FIG. 1  is a schematic diagram illustrating a geographical area that is served by FSS satellites and by a BWA network. Referring now to  FIG. 1 , a satellite  110  may communicate with a terrestrial FSS receiver  120  using suitable satellite communication frequencies such as the C-band. The FSS receiver  120  may be in the same geographic area as a BWA network including elements such as a base station  130 , a base station controller  140 , and UEs  150 . Communication between the base station  130  and one or more of the UEs  150  may use the C-band and thus the BWA network communications may interfere with satellite downlink signals received at the FSS receiver  120 . Various base stations  130  may coordinate usage of the C-band spectrum in overlapping base station geographical coverage areas. A monitor station  160  may be placed in close proximity to the FSS receiver  120  in order to effectively listen to BWA communications received by the FSS receiver  120 . The monitor station  160  may be a passive listening device to detect BWA signals falling within the FSS receiver&#39;s operating range. The monitor station  160  may provide information regarding FSS signals to elements of the BWA network wirelessly in a different band from the C-band or by a wireline connection. In order to allocate C-band resources in a terrestrial network such as a BWA network, first C-band resources used for a Fixed Satellite Service (FSS) may be determined and an allocation of second C-band resources for a terrestrial Broadband Wireless Access (BWA) network may be determined based on both (i) channel state information associated with the terrestrial BWA network and (ii) the first C-band resources used for the FSS. 
     The user equipment  150  may be (or may be a part of) one of various types of wireless electronic user devices, including mobile/cell phones, as well as wireless user devices without phone capabilities. For example, the user equipment  150  may be a smartphone, a laptop computer, a tablet computer, or any other portable, wireless electronic device with communications capability. The user equipment  150  can be located anywhere inside a geographical area serviced by a base station  130 . 
     Referring now to  FIG. 2 , FSS downlink data may be transmitted from the satellite  110  to the FSS receiver  120  of  FIG. 1 . FSS downlink data may include broadcast television or other types of data. The FSS downlink data may have gaps or blanking intervals between segments of data. These gaps or blanking intervals may occur periodically or aperiodically. The BWA network may send co-channel communications during time periods that coincide with these gaps in the FSS downlink data. Elements in the BWA network such as base station  130 , UE  150 , or monitor station  160  of  FIG. 1  may detect these time gaps in the FSS downlink data. In some embodiments, the FSS receiver  120  or an FSS network controller may be aware of the characteristics of the FSS downlink data and may provide this information to one or more elements in the BWA network. Such coordination between the FSS network and the BWA network may allow collaboration for effective reuse of the C-band frequencies for both satellite communications and terrestrial communications. The BWA network elements may thus transmit and/or receive BWA transmissions during the time gaps in the FSS downlink data. 
     In some embodiments, coordination may not be possible between the FSS network and the BWA network since it may be difficult to update network topology changes in either network. However, in some embodiments, coordination between the FSS network and the BWA network may not be necessary for both networks to coexist using the C-band. Referring now to  FIG. 3 , FSS downlink data may be transmitted from the satellite  110  to the FSS receiver  120  of  FIG. 1 . However, the BWA network may send BWA transmissions during the same time or during overlapping times with the FSS downlink data. These BWA transmissions may occur between the UE  150  and the base station  130 , between the UE  150  and the base station controller  140 , between the base station controller  140  and the UE  150 , and/or between the base station controller  140  and the base station  130  in either the uplink or downlink directions between the various network elements. The BWA transmissions may be of higher power than the FSS downlink data received at the FSS receiver and thus may corrupt the FSS downlink data. However, the BWA transmissions may occur infrequently such that a small portion of the FSS downlink data is corrupted by the BWA transmissions. Thus the FSS downlink may use Forward Error Correction (FEC) to correct errors in the FSS downlink data. FEC is a technique used for controlling errors in data transmission over unreliable or noisy communication channels. The FSS downlink data may be encoded to include some redundancy by using an error correcting code (ECC) such as a Hamming code. The redundancy in the error correcting code allows the FSS receiver to detect a limited number of errors that may occur in the FSS downlink data and/or correct these errors without retransmission. The use of FEC by the FSS receiver  120  may thus improve the reliability of the FSS downlink. 
     The carriers associated with C-band channels may have some spectral energy in adjacent channels.  FIG. 4A  illustrate an adjacent channel power ratio. Referring now to  FIG. 4A , the adjacent channel power ratio (ACPR) may be determined based on the equation ACPR=10*log 10 (P adj /P ref ) where P adj  is the power in the adjacent channel and P ref  is the reference power in a given channel. Guard bands between adjacent channels may be present to reduce the spectral energy that bleeds into the adjacent channels. However, these guards band may have fairly low spectral energy with respect to the carrier in a given C-band channel. Additionally, out-of-band (OoB) emission limits for satellite channels may be specified for the guard bands. RF carriers, such as those used in satellite communication may not have an immediate falloff at the edge of the carrier. The carrier&#39;s spectral energy may gently decay over about 10% of the bandwidth (i.e. 10% on each side of the carrier). In a Phase Shift Keying System (PSK) based system like FSS, a 30 MHz carrier would have the majority of the carrier&#39;s power in 24 MHz. This carrier would be operating in the center of the 30 MHz channel allocation. The 3 MHz guard band on either side of the carrier would give the carrier sufficient spectrum so it rolls off to noise level by the time it reaches the neighboring channel. Depending upon the carrier bandwidth, the guard band bandwidth may be different. 
     In some embodiments, the BWA network may use guard bands between C-band channels for BWA communications. In some embodiments, it may be understood that the guard band may be a part of the spectrum where a roll off of the signal at the edge of a channel has occurred. A guard band may be at an edge of the allocated spectrum or between adjacent carriers in a band. Referring now to  FIG. 4B , the C-band spectrum is partitioned into C-band channels used for satellite communications. Adjacent C-band channels may have guard bands that include C-band frequencies that are not used for satellite communication and have very low spectral energy from satellite downlink communications in the various C-band channels. The BWA network may use these guard bands for BWA transmissions between various BWA network elements such as base station  130 , base station controller  140 , UEs  150 , and/or monitor station  160  of  FIG. 1 . The BWA transmissions on the C-band guard bands thus would have very low interference with the FSS downlink received by the FSS receiver. 
     In some embodiments, the C-band channel usage may be coordinated between the FSS and the BWA network. The FSS C-band spectrum may be divided into FSS sub-bands. A coordinated effort between FSS operators and BWA network operators may allow specific FSS sub-bands to be allocated for use for terrestrial communications in the BWA network. As such, these terrestrially allocated FSS sub-bands would not be used in the FSS downlink. Referring now to  FIG. 5 , in an example embodiment, FSS sub-band #4 may be allocated and used for BWA transmissions by various BWA network elements such as base station  130 , base station controller  140 , UEs  150 , and/or monitor station  160  of  FIG. 1 . Changes for FSS sub-band usage may be coordinated between FSS operators and BWA network operators as additional satellite or BWA users come online or leave the networks. 
     Referring now to  FIG. 6 , monitor station  605  may correspond to monitor station  160  of  FIG. 1 , base station controller  615  may correspond to base station controller  140  of  FIG. 1 , base station  625  may correspond to base station  130  of  FIG. 1 , and UE  635  may correspond to UE  150  of  FIG. 1 . Monitor station  605  may be in close proximity to, co-located with, or integrated with the FSS receiver  120  of  FIG. 1 . Monitor station  605  may include a receiver configured to listen for activity on C-band frequencies, with emphasis on FSS downlink signals, at  610 . The monitor station  605  may discern C-band frequencies, channels, sub-bands, and time slots in use by C-band downlink communications to the FSS receiver  120  of  FIG. 1 . The monitor station  605  may provide this information to one or more elements in the BWA network, at  620 . The base station controller  615  may inform the base station  625  of resources such as times/frequencies that cannot be used by the BWA network, at  630 . The base station  625  may assign acceptable time slots and/or frequencies to the UE  635  for use in communication within the BWA network, at  640 . The base station  625  and the UE  635  may communicate via these assigned time slots and/or frequencies, at  650 . 
     Referring to  FIG. 7 , a block diagram is provided of a wireless electronic device which may correspond to one more of various BWA network elements such as base station  130 , base station controller  140 , UEs  150 , and/or monitor station  160  of  FIG. 1 , according to some embodiments. As illustrated in  FIG. 7 , a wireless electronic device  701  may include an antenna system  746 , a transceiver  742 , a processor (e.g., processor circuit)  751 , and a memory  753 . Moreover, the wireless electronic device  701  may optionally include a display  754 , a user interface  752 , and/or a microphone/speaker  750 . 
     A transmitter portion of the transceiver  742  may convert information, which is to be transmitted by the wireless electronic device  701 , into electromagnetic signals suitable for radio communications. A receiver portion of the transceiver  742  may demodulate electromagnetic signals, which are received by the wireless electronic device  701 . The transceiver  742  may include transmit/receive circuitry (TX/RX) that provides separate communication paths for supplying/receiving RF signals to different radiating elements of the antenna system  746  via their respective RF feeds. Accordingly, when the antenna system  746  includes two active antenna elements, the transceiver  742  may include two transmit/receive circuits  743 ,  745  connected to different ones of the antenna elements via the respective RF feeds. For example, the transmit/receive circuit  743  may be connected to a Wi-Fi antenna or a close/short-range (e.g., a Near-Field Communication (NFC) or BLUETOOTH®) antenna, whereas the transmit/receive circuit  745  may be connected to a cellular antenna or a 3G, 4G, LTE, or 5G antenna. Moreover, the antenna system  746 /transceiver  742  may include a GPS receiver. 
     Referring still to  FIG. 7 , the memory  753  can store computer program instructions that, when executed by the processor circuit  751 , carry out operations of the wireless electronic device  701 . In some embodiments, the memory  753  can be a non-transitory computer readable storage medium including computer readable program code therein that when executed by the processor  751  causes the processor  751  to perform a method described herein. As an example, the memory  753  can store the resident application described herein, which can perform the operations illustrated in various blocks of the flow charts of  FIGS. 9 to 17 . The memory  753  can be, for example, a non-volatile memory, such as a flash memory, that retains the stored data while power is removed from the memory  753 . 
       FIG. 8  illustrates a block diagram of an example processor  751  and memory  753  that may be used in accordance with various embodiments of the present inventive concepts. The processor  751  communicates with the memory  753  via an address/data bus  890 . The processor  751  may be, for example, a commercially available or custom microprocessor. Moreover, the processor  751  may include multiple processors. The memory  753  is representative of the overall hierarchy of memory devices containing the software and data used to implement various functions as described herein. The memory  753  may include, but is not limited to, the following types of devices: cache, ROM, PROM, EPROM, EEPROM, flash, Static RAM (SRAM), and Dynamic RAM (DRAM). 
     Referring to  FIG. 8 , the memory  753  may hold various categories of software and data, such as an operating system  883 . The processor  751  and memory  753  may be part of a wireless electronic device  701 . Accordingly, the operating system  883  can control operations of the wireless electronic device  701 . In particular, the operating system  883  may manage the resources of the wireless electronic device  701  and may coordinate execution of various programs (e.g., a resident application described herein) by the processor  751 . 
       FIGS. 9 to 17  are flowcharts of operations for reducing interference at a FSS receiver  120 . Referring to  FIG. 9 , C-band resources are allocated, at block  900 . First C-band resources may be determined as being used for a FSS, at block  910 . An allocation of second C-band resources for terrestrial BWA may be determined, based on both channel state information and the first C-band resources, at block  920 . 
       FIG. 10  is flowchart of operations for reducing interference at a FSS receiver  130  that may correspond to  FIG. 2 . Referring to  FIG. 10 , an allocation of the second C-band resources for terrestrial BWA may be determined, at block  920 . The second C-band resources for the terrestrial BWA network for BWA transmission during a time gap  220  between the first FSS downlink data  210  and the second FSS downlink data  230  may be allocated, at block  1010 . 
       FIG. 11  is flowchart of operations for reducing interference at a FSS receiver that may correspond to  FIG. 2 . Referring to  FIG. 11 , the time gap  220  between the first downlink data  210  and the second downlink data  230  may be identified, at block  1110 . BWA data may be transmitted during the time gap between elements of the BWA network such as base station  130 , UE  150 , or monitor station  160  of  FIG. 1 , at block  1120 . 
       FIG. 12  is flowchart of operations for reducing interference at a FSS receiver  120  that may correspond to  FIG. 3 . Referring to  FIG. 12 , an allocation of the second C-band resources for terrestrial BWA may be determined, based on the first C-band resources used by the FSS, at block  920 . The second C-band resources for the terrestrial BWA network may be allocated such that they overlap in time with the FSS downlink data, at block  1210 . This allocation of overlapping C-band resources may interfere with signals received by the FSS receiver, causing errors in the FSS downlink data  210 . Forward Error Correction (FEC) may be performed on the FSS downlink data  210  to reduce errors and/or improve the reliability of the data by transmitting a Forward Error Correction code  310 , at block  1220 . 
       FIG. 13  is flowchart of operations for reducing interference at a FSS receiver  120  that may correspond to  FIG. 4B . Referring to  FIG. 13 , an allocation of the second C-band resources for terrestrial BWA may be determined, based on the first C-band resources used by the FSS, at block  920 . The first C-band resources used for the FSS may include FSS downlink data distributed across a first C-band channel  410 , a second C-band channel  430  and/or a third C-band channel  450 . The second C-band resources for the terrestrial BWA network may be allocated in a guard band  420  that is between the first C-band channel  410  and the second C-band channel  430 , at block  1310 . BWA transmission  460  by a base station  130  and/or a user equipment (UE)  150  using the second C-band resources for the terrestrial BWA network that were allocated in the guard band  420  may not interfere with the first C-band channel  410  and/or the second C-band channel  430 . Similarly, BWA transmission  470  may be sent during a second guard band  440  that occurs between the second C-band channel  430  and the third C-band channel  450 . 
       FIG. 14  is flowchart of operations for reducing interference at a FSS receiver  120  that may correspond to  FIG. 5 . The first C-band resources used for the FSS may include a plurality of first FSS sub-bands  510 ,  520 ,  530 ,  550 ,  560  used by the FSS. Referring to  FIG. 14 , an allocation of the second C-band resources for terrestrial BWA may be determined, based on the first C-band resources, at block  920 . A second FSS sub-band may be allocated for communication between a base station  130  and/or a user equipment (UE)  150  in the terrestrial BWA network, at block  1410 . The second FSS sub-band  540  may be different from sub-bands of the first FSS sub-bands. Allocating the second FSS sub-band  540  is performed by a base station controller  140  or by the base station  130 . 
       FIG. 15  is flowchart of operations for reducing interference at a FSS receiver  120  that may correspond to  FIG. 6 . The first C-band resources used for the FSS may include a plurality of first FSS sub-bands used by the FSS. Referring to  FIG. 15 , an allocation of the second C-band resources for terrestrial BWA may be determined, based on the first C-band resources, at block  920 . Time slot information and/or frequency information associated with transmissions in the terrestrial BWA network may be received at a base station controller  140  from a monitor station  160 , at block  1510 . Available time slots and/or available frequency channels based on the time slot information and/or the frequency information may be determined, at block  1520 . Information associated with the available time slots and/or available frequency channels may be sent to a base station  130  in the terrestrial BWA network for assignment for communication with one or more user equipments (UEs)  150 , at block  1530 . 
       FIG. 16  is flowchart of operations for reducing interference at a FSS receiver  120 . First C-band resources used for a FSS may be determined, at block  910 . Information identifying the first C-band resources used for the FSS may be received by the base station controller  140  or the base station  130 , at block  1610 . The first C-band resources used for the FSS may be determined based on the information identifying the first C-band resources used for FSS, at block  1620 . 
       FIG. 17  is flowchart of operations for reducing interference at a FSS receiver  120 . C-band resources may be allocated at block  1700 . The allocation of the second C-band resources for the terrestrial BWA network may be communicated to a base station  130  and/or a user equipment (UE)  150  in the terrestrial BWA network for use in BWA communication between the base station  130  and the UE  150 , at block  1710 . 
     A variety of different embodiments of the present inventive concepts have been disclosed herein, in connection with the above description and the drawings. It will be understood that it would be unduly repetitious and obfuscating to literally describe and illustrate every combination and subcombination of these embodiments. Accordingly, the present specification, including the drawings, shall be construed to constitute a complete written description of all combinations and subcombinations of the embodiments of the present inventive concepts described herein, and of the manner and process of making and using them, and shall support claims to any such combination or subcombination. 
     It will be understood that when an element is referred to as being “connected,” “coupled,” or “responsive” to another element, it can be directly connected, coupled, or responsive to the other element or intervening elements may be present. Furthermore, “connected,” “coupled,” or “responsive” as used herein may include wirelessly connected, coupled, or responsive. 
     The terminology used herein is for the purpose of describing particular embodiments of the present inventive concepts only and is not intended to be limiting of the present inventive concepts. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless expressly stated otherwise. It will be further understood that the terms “includes,” “comprises,” “including,” and/or “comprising,” when used in this specification, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. The symbol “/” is also used as a shorthand notation for “and/or.” 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present inventive concepts belong. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     It will be understood that although the terms “first” and “second” may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. Thus, a first element could be termed a second element, and similarly, a second element may be termed a first element without departing from the teachings of the present inventive concepts. 
     A variety of different embodiments of the present inventive concepts have been disclosed herein, in connection with the above description and the drawings. It will be understood that it would be unduly repetitious and obfuscating to literally describe and illustrate every combination and subcombination of these embodiments. Accordingly, the present specification, including the drawings, shall be construed to constitute a complete written description of all combinations and subcombinations of the embodiments of the present inventive concepts described herein, and of the manner and process of making and using them, and shall support claims to any such combination or subcombination. 
     In the drawings and specification, there have been disclosed example embodiments of the present inventive concepts. Although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the present inventive concepts being defined by the following claims.