Signal to leakage ratio optimization (SLRO) for analog hybrid matrix sector power

Abstract

A method and multi-sector radios for signal to leakage ratio optimization (SLRO) for analog hybrid matrix (AHM) sector power are disclosed. In some embodiments, a method in multi-sector radio includes distributing power of a plurality of sector input signals for a plurality of carriers and sectors via a digital hybrid matrix (DHM) to a plurality of transmit chains, each transmit chain configured to output a transmit chain output signal. The method includes determining via the AHM, a sector output signal for each sector. A portion of the power of each sector output signal provides a feedback signal for each sector to processing circuitry. The method further includes determining a leakage value for each of a plurality of frequency domain sections and for each sector based on the feedback signals. The method also includes adjusting values of the DHM based on the determined leakage values.

Description

[0001]SIGNAL TO LEAKAGE RATIO OPTIMIZATION (SLRO) FOR ANALOG HYBRID MATRIX SECTOR POWER TECHNICAL FIELD The present disclosure relates to wireless communications, and in particular, to signal to leakage ratio optimization (SLRO) for analog hybrid matrix (AHM) sector power. BACKGROUND The Third Generation Partnership Project (3GPP) has developed and is developing standards for Fourth Generation (4G) (also referred to as Long Term Evolution (LTE)) and Fifth Generation (5G) (also referred to as New Radio (NR)) wireless communication systems. Such systems provide, among other features, broadband communication between network nodes, such as base stations, and mobile wireless devices (WD), as well as communication between network nodes and between WDs. The 3GPP is also considering standards for Sixth Generation (6G) wireless communication networks. As air interfaces (technologies) become more complex to meet the ever increasing demand for wireless voice and data services, the number of radios being deployed is increasing and the required signal quality of those radios is also increasing. At the same time, there is increased focus on reducing power consumption. An option for helping to reduce power consumption is to make multi-sector radios that have power amplifiers connected with an analog hybrid matrix (AHM) and used together with a digital hybrid matrix (DHM). This allows power sharing between sectors. This also allows a reduction in power amplifier size while still meeting the statistical RF power demands of the network, which in turn reduces power consumption. However the AHM is not ideal so the DHM needs Signal to Leakage Ratio Optimization (SLRO) using an algorithm that can meet the required signal quality. Existing solutions use a DHM composed of a single complex multiplier for each branch which may only improve the SLR up to a limit. This arrangement is not suitable for wider band carriers and / or more advanced technologies with high signal quality requirements. SUMMARY Some embodiments advantageously provide methods and multi-sector radios for signal to leakage ratio optimization (SLRO) for analog hybrid matrix (AHM) sector power. Some embodiments include a multi-sector radio configured to provide signal to leakage ratio optimization (SLRO) that compensates for the non-ideal properties of the AHM to minimize the signal to leakage ratio for each carrier of each sector served by the multi-sector radio. Some embodiments include a multi-sector radio configured to provide SLRO by determining the complex leakage levels at each sector output and to determine updated DHM values based on subtracting an amount from the DHM values based on the complex leakage levels. In some embodiments, the complex leakage level determination relies on a transfer function which is determined iteratively. The SLRO algorithms disclosed herein may need only a small number of iterations to reach an optimum set of SLRs for the sectors served by the multi-sector radio. In some embodiments, SLRO algorithms disclosed herein operate in the frequency domain. Therefore, variations in AHM properties as a function of carrier frequency may be compensated by dividing the frequency domain into multiple frequency domain sections. A DHM value is determined for each frequency domain section. Then an equalizer may be used to provide DHM values as a function of frequency as determined for each frequency domain section. In some embodiments, SLRO algorithms disclosed herein use feedback signals coupled directly from the outputs of the AHM. In some embodiments, SLRO algorithms disclosed herein use feedback signals coupled directly from filtered outputs of the AHM. In some embodiments, SLRO algorithms disclosed herein operate on each sector so that any sector filter frequency variation will be canceled. This allows for coupling filtered outputs of the AHM to produce feedback signals to the SLRO algorithms. This is an advantage since couplers positioned after the filter are typically already required in typical applications. Some embodiments may have one or more of the following advantages compared to known solutions: • Works for wide band carriers; • Works for high signal quality requirements; • Compensated for AHM frequency variation • Can work with couplers after the filter; and / or • Very fast convergence. According to one aspect, a multi-sector radio configured to operate in a network node and configured to communicate with a plurality of wireless devices, WDs, is provided. The multi-sector radio includes a digital hybrid matrix, DHM, configured to receive a sector input signal for each of a plurality of carriers and a plurality of sectors. The DHM is also configured to distribute power of the sector input signals to a plurality of transmit chains, each transmit chain configured to output a transmit chain output signal. The multi-sector radio also includes an analog hybrid matrix, AHM, configured to receive the transmit chain output signals and to output a sector output signal for each sector. The multi-sector radio also includes a plurality of couplers, one coupler for each sector of the plurality of sectors, each coupler configured to couple power of the sector output signal to provide a feedback signal to processing circuitry. The multi-sector further includes the processing circuitry, the processing circuitry configured to receive the feedback signals and: determine a leakage value for each of a plurality of frequency domain sections and for each sector of the plurality of sectors based at least in part on the feedback signals; and adjust values of the DHM based at least in part on the determined leakage values. According to this aspect, in some embodiments, the DHM is configured to distribute power to carriers grouped in a plurality of frequency bands, and the multi-sector radio includes an equalizer configured to perform equalization of power of the plurality of frequency bands. In some embodiments, the DHM values are adjusted to optimize a signal to leakage ratio for each sector of the plurality of sectors. In some embodiments, adjusting the DHM values to optimize the signal to leakage ratio for each sector of the plurality of sectors includes determining a set of DHM values that produces a first set of optimal signal to leakage ratios for the plurality of sectors. In some embodiments, the DHM values are adjusted iteratively to drive the determined leakage values toward zero. In some embodiments, updating the DHM values includes subtracting the determined leakage values from a current set of DHM values. In some embodiments, the method includes, for each sector output signal, a filter between the AHM and the coupler for the respective sector of the plurality of sectors. In some embodiments, the processing circuitry is further configured to perform a time alignment procedure to align each feedback signal with a respective reference signal. In some embodiments, the time alignment procedure includes padding each reference signal with at least one zero and padding each feedback signal with at least one zero. In some embodiments, the processing circuitry is further configured to determine a Fourier transform of a first concatenated sum of the zero padded reference signals and to determine a Fourier transform of a second concatenated sum of the zero padded feedback signals. In some embodiments, the processing circuitry is further configured to pad the Fourier transformed first concatenated sum with at least one zero and to pad the Fourier transformed second concatenated sum with at least one zero. In some embodiments, the processing circuitry is further configured to determine a maximum of a cross correlation, the cross correlation being determined in the frequency domain based at least in part on a convolution of the zero padded Fourier transformed first concatenated sum and a conjugate of the zero padded Fourier transformed second concatenated sum and to determine a fractional delay based at least in part on an index of occurrence of the maximum of the cross correlation. In some embodiments, the processing circuitry is further configured to apply the fractional delay to the zero padded feedback signals to obtain a time aligned feedback signal for each sector of the plurality of sectors. In some embodiments, adjusting the DHM values includes determining a first set of DHM values that produces a first set of optimal signal to leakage ratios for the plurality of a sectors, determining the first set of DHM values including determining, for each sector of the plurality of sectors, a maximum of an inverse Fourier transform a product of a Fourier transform of the reference signals and a Fourier transform of the feedback signals. In some embodiments, the processing circuitry is further configured to determine a power for each sector of the plurality of sectors based at least in part on the determined maximum for each sector of the plurality of sectors. In some embodiments, the processing circuitry is further configured to determine the first set of DHM values by selecting a set of phase values that produce the first set of optimal leakage ratios, the first set of phase values being selected from a range of phase values. According to another aspect, a method in a multi-sector radio configured to operate in a network node and configured to communicate with a plurality of wireless devices is provided. The method includes distributing power of a plurality of sector input signals for a plurality of carriers and a plurality of sectors via a digital hybrid matrix, DHM, to a plurality of transmit chains, each transmit chain configured to output a transmit chain output signal. The method includes determining via an analog hybrid matrix, AHM, a sector output signal for each sector. The method also includes coupling power of each sector output signal to provide a feedback signal for each sector to processing circuitry. The method further includes determining a leakage value for each of a plurality of frequency domain sections and for each sector based at least in part on the feedback signal. The method also includes adjusting values of the DHM based at least in part on the determined leakage values. According to this aspect, in some embodiments, the method also includes distributing power to the plurality of carriers grouped in a plurality of frequency bands, and performing equalization of power of the plurality of frequency bands. In some embodiments, the DHM values are adjusted to optimize a signal to leakage ratio for each sector. In some embodiments, adjusting the DHM values to optimize the signal to leakage ratio for each sector includes determining a set of DHM values among that produces a first set of optimal signal to leakage ratios for the plurality of sectors. In some embodiments, the DHM values are adjusted iteratively to drive the determined leakage values toward zero. In some embodiments, updating the DHM values includes subtracting the determined leakage values from a current set of DHM values. In some embodiments, the method includes filtering each sector output signal via a filter between the AHM and the coupler for the respective sector of the plurality of sectors. In some embodiments, the method includes performing a time alignment procedure to align each feedback signal with a respective reference signal. In some embodiments, the time alignment procedure includes padding each reference signal with at least one zero and padding each feedback signal with at least one zero. In some embodiments, the method includes determining a Fourier transform of a first concatenated sum of the zero padded reference signals and determining a Fourier transform of a second concatenated sum of the zero padded feedback signals. In some embodiments, the method includes padding the Fourier transformed first concatenated sum with at least one zero and padding the Fourier transformed second concatenated sum with at least one zero. In some embodiments, the method includes determining a maximum of a cross correlation, the cross correlation being determined in the frequency domain based at least in part on a convolution of the zero padded Fourier transformed first concatenated sum and a conjugate of the zero padded Fourier transformed second concatenated sum and determining a fractional delay based at least in part on an index of occurrence of the maximum of the cross correlation. In some embodiments, the method includes applying the fractional delay to the zero padded feedback signals to obtain a time aligned feedback signal for each sector of the plurality of sectors. In some embodiments, adjusting the DHM values includes determining a first set of DHM values that produces a first set of optimal signal to leakage ratios for the plurality of a sectors, determining the first set of DHM values including determining, for each sector of the plurality of sectors, a maximum of an inverse Fourier transform a product of a Fourier transform of the reference signals and a Fourier transform of the feedback signals. In some embodiments, the method includes determining a power for each sector of the plurality of sectors based at least in part on the determined maximum for each sector of the plurality of sectors. In some embodiments, the method includes determining the first set of DHM values by selecting a set of phase values that produce the first set of optimal leakage ratios, the first set of phase values being selected from a range of phase values. BRIEF DESCRIPTION OF THE DRAWINGS A more complete understanding of the present embodiments, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein: FIG. 1 is a schematic diagram of an example network architecture illustrating a communication system connected via an intermediate network to a host computer according to the principles in the present disclosure; FIG. 2 is a block diagram of a host computer communicating via a network node with a wireless device over an at least partially wireless connection according to some embodiments of the present disclosure; FIG. 3 is a flowchart illustrating example methods implemented in a communication system including a host computer, a network node and a wireless device for executing a client application at a wireless device according to some embodiments of the present disclosure; FIG. 4 is a flowchart illustrating example methods implemented in a communication system including a host computer, a network node and a wireless device for receiving user data at a wireless device according to some embodiments of the present disclosure; FIG. 5 is a flowchart illustrating example methods implemented in a communication system including a host computer, a network node and a wireless device for receiving user data from the wireless device at a host computer according to some embodiments of the present disclosure; FIG. 6 is a flowchart illustrating example methods implemented in a communication system including a host computer, a network node and a wireless device for receiving user data at a host computer according to some embodiments of the present disclosure; FIG. 7 is a flowchart of an example process in a network node for signal to leakage ratio optimization (SLRO) for analog hybrid matrix (AHM) sector power; FIG. 8 is a block diagram of a multi-sector radio configured according to principles disclosed herein; FIG. 9 is a signal flow graph of a combination of a digital hybrid matrix (DHM) and an AHM configured according to principles disclosed herein; and FIG. 10 is a graph that illustrates performance in a search mode of operation and an iteration mode of operation of an example SLRO algorithm configured according to principles disclosed herein. DETAILED DESCRIPTION Before describing in detail example embodiments, it is noted that the embodiments reside primarily in combinations of apparatus components and processing steps related to signal to leakage ratio optimization (SLRO) for analog hybrid matrix (AHM) sector power. Accordingly, components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Like numbers refer to like elements throughout the description. As used herein, relational terms, such as “first” and “second,” “top” and “bottom,” and the like, may be used solely to distinguish one entity or element from another entity or element without necessarily requiring or implying any physical or logical relationship or order between such entities or elements. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the concepts described herein. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and / or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. In embodiments described herein, the joining term, “in communication with” and the like, may be used to indicate electrical or data communication, which may be accomplished by physical contact, induction, electromagnetic radiation, radio signaling, infrared signaling or optical signaling, for example. One having ordinary skill in the art will appreciate that multiple components may interoperate and modifications and variations are possible of achieving the electrical and data communication. In some embodiments described herein, the term “coupled,” “connected,” and the like, may be used herein to indicate a connection, although not necessarily directly, and may include wired and / or wireless connections. The term “network node” used herein may be any kind of network node comprised in a radio network which may further comprise any of base station (BS), radio base station, base transceiver station (BTS), base station controller (BSC), radio network controller (RNC), g Node B (gNB), evolved Node B (eNB or eNodeB), Node B, multi- standard radio (MSR) radio node such as MSR BS, multi-cell / multicast coordination entity (MCE), integrated access and backhaul (IAB) node, relay node, donor node controlling relay, radio access point (AP), transmission points, transmission nodes, Remote Radio Unit (RRU) Remote Radio Head (RRH), a core network node (e.g., mobile management entity (MME), self-organizing network (SON) node, a coordinating node, positioning node, MDT node, etc.), an external node (e.g., 3rd party node, a node external to the current network), nodes in distributed antenna system (DAS), a spectrum access system (SAS) node, an element management system (EMS), etc. The network node may also comprise test equipment. The term “radio node” used herein may be used to also denote a wireless device (WD) such as a wireless device (WD) or a radio network node. In some embodiments, the non-limiting terms wireless device (WD) or a user equipment (UE) are used interchangeably. The WD herein may be any type of wireless device capable of communicating with a network node or another WD over radio signals, such as wireless device (WD). The WD may also be a radio communication device, target device, device to device (D2D) WD, machine type WD or WD capable of machine to machine communication (M2M), low-cost and / or low-complexity WD, a sensor equipped with WD, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, Customer Premises Equipment (CPE), an Internet of Things (IoT) device, or a Narrowband IoT (NB-IOT) device, etc. Also, in some embodiments the generic term “radio network node” is used. It may be any kind of a radio network node which may comprise any of base station, radio base station, base transceiver station, base station controller, network controller, RNC, evolved Node B (eNB), Node B, gNB, Multi-cell / multicast Coordination Entity (MCE), IAB node, relay node, access point, radio access point, Remote Radio Unit (RRU) Remote Radio Head (RRH). Note that although terminology from one particular wireless system, such as, for example, 3GPP LTE and / or New Radio (NR), may be used in this disclosure, this should not be seen as limiting the scope of the disclosure to only the aforementioned system. Other wireless systems, including without limitation Wide Band Code Division Multiple Access (WCDMA), Worldwide Interoperability for Microwave Access (WiMax), Ultra Mobile Broadband (UMB) and Global System for Mobile Communications (GSM), may also benefit from exploiting the ideas covered within this disclosure. Note further, that functions described herein as being performed by a wireless device or a network node may be distributed over a plurality of wireless devices and / or network nodes. In other words, it is contemplated that the functions of the network node and wireless device described herein are not limited to performance by a single physical device and, in fact, may be distributed among several physical devices. 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 this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. Some embodiments provide signal to leakage ratio optimization (SLRO) for analog hybrid matrix (AHM) sector power. Some embodiments provide a multi-sector radio with processing circuitry configured to determine an optimum set of SLRs for the sectors served by the multi-sector radio. An optimum set of SLRs may be defined as, for example, a set of SLRs that are minimized for all sectors, jointly. Referring now to the drawing figures, in which like elements are referred to by like reference numerals, there is shown in FIG. 1 a schematic diagram of a communication system 10, according to an embodiment, such as a 3GPP-type cellular network that may support standards such as LTE and / or NR (5G), which comprises an access network 12, such as a radio access network, and a core network 14. The access network 12 comprises a plurality of network nodes 16a, 16b, 16c (referred to collectively as network nodes 16), such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 18a, 18b, 18c (referred to collectively as coverage areas 18). Each network node 16a, 16b, 16c is connectable to the core network 14 over a wired or wireless connection 20. A first wireless device (WD) 22a located in coverage area 18a is configured to wirelessly connect to, or be paged by, the corresponding network node 16a. A second WD 22b in coverage area 18b is wirelessly connectable to the corresponding network node 16b. While a plurality of WDs 22a, 22b (collectively referred to as wireless devices 22) are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole WD is in the coverage area or where a sole WD is connecting to the corresponding network node 16. Note that although only two WDs 22 and three network nodes 16 are shown for convenience, the communication system may include many more WDs 22 and network nodes 16. Also, it is contemplated that a WD 22 may be in simultaneous communication and / or configured to separately communicate with more than one network node 16 and more than one type of network node 16. For example, a WD 22 may have dual connectivity with a network node 16 that supports LTE and the same or a different network node 16 that supports NR. As an example, WD 22 may be in communication with an eNB for LTE / E-UTRAN and a gNB for NR / NG-RAN. The communication system 10 may itself be connected to a host computer 24, which may be embodied in the hardware and / or software of a standalone server, a cloud- implemented server, a distributed server or as processing resources in a server farm. The host computer 24 may be under the ownership or control of a service provider, or may be operated by the service provider or on behalf of the service provider. The connections 26, 28 between the communication system 10 and the host computer 24 may extend directly from the core network 14 to the host computer 24 or may extend via an optional intermediate network 30. The intermediate network 30 may be one of, or a combination of more than one of, a public, private or hosted network. The intermediate network 30, if any, may be a backbone network or the Internet. In some embodiments, the intermediate network 30 may comprise two or more sub-networks (not shown). The communication system of FIG. 1 as a whole enables connectivity between one of the connected WDs 22a, 22b and the host computer 24. The connectivity may be described as an over-the-top (OTT) connection. The host computer 24 and the connected WDs 22a, 22b are configured to communicate data and / or signaling via the OTT connection, using the access network 12, the core network 14, any intermediate network 30 and possible further infrastructure (not shown) as intermediaries. The OTT connection may be transparent in the sense that at least some of the participating communication devices through which the OTT connection passes are unaware of routing of uplink and downlink communications. For example, a network node 16 may not or need not be informed about the past routing of an incoming downlink communication with data originating from a host computer 24 to be forwarded (e.g., handed over) to a connected WD 22a. Similarly, the network node 16 need not be aware of the future routing of an outgoing uplink communication originating from the WD 22a towards the host computer 24. A processing circuitry 68 of the multi-sector radio 58 of the network node 16 may be configured to include an SLRO unit 32 which may be configured to determining a leakage value for each of a plurality of frequency domain sections and for each sector based at least in part on the feedback signals and adjust values of the digital hybrid matrix, DHM, based at least in part on determined leakage values for a plurality of frequency domain sections. Example implementations, in accordance with an embodiment, of the WD 22, network node 16 and host computer 24 discussed in the preceding paragraphs will now be described with reference to FIG. 2. In a communication system 10, a host computer 24 comprises hardware (HW) 38 including a communication interface 40 configured to set up and maintain a wired or wireless connection with an interface of a different communication device of the communication system 10. The host computer 24 further comprises processing circuitry 42, which may have storage and / or processing capabilities. The processing circuitry 42 may include a processor 44 and memory 46. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 42 may comprise integrated circuitry for processing and / or control, e.g., one or more processors and / or processor cores and / or FPGAs (Field Programmable Gate Array) and / or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 44 may be configured to access (e.g., write to and / or read from) memory 46, which may comprise any kind of volatile and / or nonvolatile memory, e.g., cache and / or buffer memory and / or RAM (Random Access Memory) and / or ROM (Read-Only Memory) and / or optical memory and / or EPROM (Erasable Programmable Read-Only Memory). Processing circuitry 42 may be configured to control any of the methods and / or processes described herein and / or to cause such methods, and / or processes to be performed, e.g., by host computer 24. Processor 44 corresponds to one or more processors 44 for performing host computer 24 functions described herein. The host computer 24 includes memory 46 that is configured to store data, programmatic software code and / or other information described herein. In some embodiments, the software 48 and / or the host application 50 may include instructions that, when executed by the processor 44 and / or processing circuitry 42, causes the processor 44 and / or processing circuitry 42 to perform the processes described herein with respect to host computer 24. The instructions may be software associated with the host computer 24. The software 48 may be executable by the processing circuitry 42. The software 48 includes a host application 50. The host application 50 may be operable to provide a service to a remote user, such as a WD 22 connecting via an OTT connection 52 terminating at the WD 22 and the host computer 24. In providing the service to the remote user, the host application 50 may provide user data which is transmitted using the OTT connection 52. The “user data” may be data and information described herein as implementing the described functionality. In one embodiment, the host computer 24 may be configured for providing control and functionality to a service provider and may be operated by the service provider or on behalf of the service provider. The processing circuitry 42 of the host computer 24 may enable the host computer 24 to observe, monitor, control, transmit to and / or receive from the network node 16 and or the wireless device 22. The communication system 10 further includes a network node 16 provided in a communication system 10 and including hardware enabling it to communicate with the host computer 24 and with the WD 22. The hardware may a multi-sector radio 58 that and a communication interface 60 for setting up and maintaining a wired or wireless connection with an interface of a different communication device of the communication system 10, as well as a radio interface 62 for setting up and maintaining at least a wireless connection 64 with a WD 22 located in a coverage area 18 served by the network node 16. The radio interface 62 may be formed as or may include, for example, one or more RF transmitters, one or more RF receivers, and / or one or more RF transceivers. The communication interface 60 may be configured to facilitate a connection 66 to the host computer 24. The connection 66 may be direct or it may pass through a core network 14 of the communication system 10 and / or through one or more intermediate networks 30 outside the communication system 10. In the embodiment shown, the multi-sector radio 58 of the network node 16 further includes processing circuitry 68. The processing circuitry 68 may include a processor 70 and a memory 72. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 68 may comprise integrated circuitry for processing and / or control, e.g., one or more processors and / or processor cores and / or FPGAs (Field Programmable Gate Array) and / or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 70 may be configured to access (e.g., write to and / or read from) the memory 72, which may comprise any kind of volatile and / or nonvolatile memory, e.g., cache and / or buffer memory and / or RAM (Random Access Memory) and / or ROM (Read-Only Memory) and / or optical memory and / or EPROM (Erasable Programmable Read-Only Memory). Thus, the network node 16 further has software 74 stored internally in, for example, memory 72, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the network node 16 via an external connection. The software 74 may be executable by the processing circuitry 68. The processing circuitry 68 may be configured to control any of the methods and / or processes described herein and / or to cause such methods, and / or processes to be performed, e.g., by network node 16, including the multi-sector radio 58. Processor 70 corresponds to one or more processors 70 for performing network node 16 functions described herein. The memory 72 is configured to store data, programmatic software code and / or other information described herein. In some embodiments, the software 74 may include instructions that, when executed by the processor 70 and / or processing circuitry 68, causes the processor 70 and / or processing circuitry 68 to perform the processes described herein with respect to network node 16 and the multi-sector radio 58. For example, processing circuitry 68 of the network node 16 may include an SLRO unit 32 which may be configured to determining a leakage value for each of a plurality of frequency domain sections and for each sector based at least in part on the feedback signals and adjust values of the digital hybrid matrix, DHM, based at least in part on determined leakage values for a plurality of frequency domain sections. The communication system 10 further includes the WD 22 already referred to. The WD 22 may have hardware 80 that may include a radio interface 82 configured to set up and maintain a wireless connection 64 with a network node 16 serving a coverage area 18 in which the WD 22 is currently located. The radio interface 82 may be formed as or may include, for example, one or more RF transmitters, one or more RF receivers, and / or one or more RF transceivers. The hardware 80 of the WD 22 further includes processing circuitry 84. The processing circuitry 84 may include a processor 86 and memory 88. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 84 may comprise integrated circuitry for processing and / or control, e.g., one or more processors and / or processor cores and / or FPGAs (Field Programmable Gate Array) and / or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 86 may be configured to access (e.g., write to and / or read from) memory 88, which may comprise any kind of volatile and / or nonvolatile memory, e.g., cache and / or buffer memory and / or RAM (Random Access Memory) and / or ROM (Read-Only Memory) and / or optical memory and / or EPROM (Erasable Programmable Read-Only Memory). Thus, the WD 22 may further comprise software 90, which is stored in, for example, memory 88 at the WD 22, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the WD 22. The software 90 may be executable by the processing circuitry 84. The software 90 may include a client application 92. The client application 92 may be operable to provide a service to a human or non-human user via the WD 22, with the support of the host computer 24. In the host computer 24, an executing host application 50 may communicate with the executing client application 92 via the OTT connection 52 terminating at the WD 22 and the host computer 24. In providing the service to the user, the client application 92 may receive request data from the host application 50 and provide user data in response to the request data. The OTT connection 52 may transfer both the request data and the user data. The client application 92 may interact with the user to generate the user data that it provides. The processing circuitry 84 may be configured to control any of the methods and / or processes described herein and / or to cause such methods, and / or processes to be performed, e.g., by WD 22. The processor 86 corresponds to one or more processors 86 for performing WD 22 functions described herein. The WD 22 includes memory 88 that is configured to store data, programmatic software code and / or other information described herein. In some embodiments, the software 90 and / or the client application 92 may include instructions that, when executed by the processor 86 and / or processing circuitry 84, causes the processor 86 and / or processing circuitry 84 to perform the processes described herein with respect to WD 22. In some embodiments, the inner workings of the network node 16, WD 22, and host computer 24 may be as shown in FIG. 2 and independently, the surrounding network topology may be that of FIG. 1. In FIG. 2, the OTT connection 52 has been drawn abstractly to illustrate the communication between the host computer 24 and the wireless device 22 via the network node 16, without explicit reference to any intermediary devices and the precise routing of messages via these devices. Network infrastructure may determine the routing, which it may be configured to hide from the WD 22 or from the service provider operating the host computer 24, or both. While the OTT connection 52 is active, the network infrastructure may further take decisions by which it dynamically changes the routing (e.g., on the basis of load balancing consideration or reconfiguration of the network). The wireless connection 64 between the WD 22 and the network node 16 is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to the WD 22 using the OTT connection 52, in which the wireless connection 64 may form the last segment. More precisely, the teachings of some of these embodiments may improve the data rate, latency, and / or power consumption and thereby provide benefits such as reduced user waiting time, relaxed restriction on file size, better responsiveness, extended battery lifetime, etc. In some embodiments, a measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection 52 between the host computer 24 and WD 22, in response to variations in the measurement results. The measurement procedure and / or the network functionality for reconfiguring the OTT connection 52 may be implemented in the software 48 of the host computer 24 or in the software 90 of the WD 22, or both. In embodiments, sensors (not shown) may be deployed in or in association with communication devices through which the OTT connection 52 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which software 48, 90 may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 52 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not affect the network node 16, and it may be unknown or imperceptible to the network node 16. Some such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary WD signaling facilitating the host computer’s 24 measurements of throughput, propagation times, latency and the like. In some embodiments, the measurements may be implemented in that the software 48, 90 causes messages to be transmitted, in particular empty or ‘dummy’ messages, using the OTT connection 52 while it monitors propagation times, errors, etc. Thus, in some embodiments, the host computer 24 includes processing circuitry 42 configured to provide user data and a communication interface 40 that is configured to forward the user data to a cellular network for transmission to the WD 22. In some embodiments, the cellular network also includes the network node 16 with a radio interface 62. In some embodiments, the network node 16 is configured to, and / or the network node’s 16 processing circuitry 68 is configured to perform the functions and / or methods described herein for preparing / initiating / maintaining / supporting / ending a transmission to the WD 22, and / or preparing / terminating / maintaining / supporting / ending in receipt of a transmission from the WD 22. In some embodiments, the host computer 24 includes processing circuitry 42 and a communication interface 40 that is configured to a communication interface 40 configured to receive user data originating from a transmission from a WD 22 to a network node 16. In some embodiments, the WD 22 is configured to, and / or comprises a radio interface 82 and / or processing circuitry 84 configured to perform the functions and / or methods described herein for preparing / initiating / maintaining / supporting / ending a transmission to the network node 16, and / or preparing / terminating / maintaining / supporting / ending in receipt of a transmission from the network node 16. Although FIGS. 1 and 2 show various “units” such as SLRO unit 32 as being within a respective processor, it is contemplated that these units may be implemented such that a portion of the unit is stored in a corresponding memory within the processing circuitry. In other words, the units may be implemented in hardware or in a combination of hardware and software within the processing circuitry. FIG. 3 is a flowchart illustrating an example method implemented in a communication system, such as, for example, the communication system of FIGS. 1 and 2, in accordance with one embodiment. The communication system may include a host computer 24, a network node 16 and a WD 22, which may be those described with reference to FIG. 2. In a first step of the method, the host computer 24 provides user data (Block S100). In an optional substep of the first step, the host computer 24 provides the user data by executing a host application, such as, for example, the host application 50 (Block S102). In a second step, the host computer 24 initiates a transmission carrying the user data to the WD 22 (Block S104). In an optional third step, the network node 16 transmits to the WD 22 the user data which was carried in the transmission that the host computer 24 initiated, in accordance with the teachings of the embodiments described throughout this disclosure (Block S106). In an optional fourth step, the WD 22 executes a client application, such as, for example, the client application 92, associated with the host application 50 executed by the host computer 24 (Block S108). FIG. 4 is a flowchart illustrating an example method implemented in a communication system, such as, for example, the communication system of FIG. 1, in accordance with one embodiment. The communication system may include a host computer 24, a network node 16 and a WD 22, which may be those described with reference to FIGS. 1 and 2. In a first step of the method, the host computer 24 provides user data (Block S110). In an optional substep (not shown) the host computer 24 provides the user data by executing a host application, such as, for example, the host application 50. In a second step, the host computer 24 initiates a transmission carrying the user data to the WD 22 (Block S112). The transmission may pass via the network node 16, in accordance with the teachings of the embodiments described throughout this disclosure. In an optional third step, the WD 22 receives the user data carried in the transmission (Block S114). FIG. 5 is a flowchart illustrating an example method implemented in a communication system, such as, for example, the communication system of FIG. 1, in accordance with one embodiment. The communication system may include a host computer 24, a network node 16 and a WD 22, which may be those described with reference to FIGS. 1 and 2. In an optional first step of the method, the WD 22 receives input data provided by the host computer 24 (Block S116). In an optional substep of the first step, the WD 22 executes the client application 92, which provides the user data in reaction to the received input data provided by the host computer 24 (Block S118). Additionally or alternatively, in an optional second step, the WD 22 provides user data (Block S120). In an optional substep of the second step, the WD provides the user data by executing a client application, such as, for example, client application 92 (Block S122). In providing the user data, the executed client application 92 may further consider user input received from the user. Regardless of the specific manner in which the user data was provided, the WD 22 may initiate, in an optional third substep, transmission of the user data to the host computer 24 (Block S124). In a fourth step of the method, the host computer 24 receives the user data transmitted from the WD 22, in accordance with the teachings of the embodiments described throughout this disclosure (Block S126). FIG. 6 is a flowchart illustrating an example method implemented in a communication system, such as, for example, the communication system of FIG. 1, in accordance with one embodiment. The communication system may include a host computer 24, a network node 16 and a WD 22, which may be those described with reference to FIGS. 1 and 2. In an optional first step of the method, in accordance with the teachings of the embodiments described throughout this disclosure, the network node 16 receives user data from the WD 22 (Block S128). In an optional second step, the network node 16 initiates transmission of the received user data to the host computer 24 (Block S130). In a third step, the host computer 24 receives the user data carried in the transmission initiated by the network node 16 (Block S132). FIG. 7 is a flowchart of an example process in a network node 16 for signal to leakage ratio optimization (SLRO) for analog hybrid matrix (AHM) sector power. One or more blocks described herein may be performed by one or more elements of network node 16 such as by one or more of processing circuitry 68 (including the SLRO unit 32), processor 70, radio interface 62 and / or communication interface 60. Network node 16 such as via processing circuitry 68 and / or processor 70 and / or radio interface 62 and / or communication interface 60 is configured to distribute power of a plurality of sector input signals for a plurality of carriers and a plurality of sectors via a digital hybrid matrix, DHM, to a plurality of transmit chains, each transmit chain configured to output a transmit chain output signal (Block S134). The process includes determining via an analog hybrid matrix, AHM, a sector output signal for each sector (Block S136). The process also includes coupling power of each sector output signal to provide a feedback signal for each sector to processing circuitry (Block S138). The process further includes determining a leakage value for each of a plurality of frequency domain sections and for each sector based at least in part on the feedback signals (Block S140). The process includes adjusting values of the DHM based at least in part on the determined leakage values (Block S142). In some embodiments, the process includes distributing power to the plurality of carriers grouped in a plurality of frequency bands, and performing equalization of power of the plurality of frequency bands. In some embodiments, the DHM values are adjusted to optimize a signal to leakage ratio for each sector. In some embodiments, adjusting the DHM values to optimize the signal to leakage ratio for each sector includes determining a set of DHM values among that produces a first set of optimal signal to leakage ratios for the plurality of sectors. In some embodiments, the DHM values are adjusted iteratively to drive the determined leakage values toward zero. In some embodiments, updating the DHM values includes subtracting the determined leakage values from a current set of DHM values. In some embodiments, the process includes filtering each sector output signal via a filter between the AHM and the coupler for the respective sector of the plurality of sectors. In some embodiments, the process includes performing a time alignment procedure to align each feedback signal with a respective reference signal. In some embodiments, the time alignment procedure includes padding each reference signal with at least one zero and padding each feedback signal with at least one zero. In some embodiments, the process includes determining a Fourier transform of a first concatenated sum of the zero padded reference signals and determining a Fourier transform of a second concatenated sum of the zero padded feedback signals. In some embodiments, the process includes padding the Fourier transformed first concatenated sum with at least one zero and padding the Fourier transformed second concatenated sum with at least one zero. In some embodiments, the process includes determining a maximum of a cross correlation, the cross correlation being determined in the frequency domain based at least in part on a convolution of the zero padded Fourier transformed first concatenated sum and a conjugate of the zero padded Fourier transformed second concatenated sum and determining a fractional delay based at least in part on an index of occurrence of the maximum of the cross correlation. In some embodiments, the process includes applying the fractional delay to the zero padded feedback signals to obtain a time aligned feedback signal for each sector of the plurality of sectors. In some embodiments, the process includes adjusting the DHM values includes determining a first set of DHM values that produces a first set of optimal signal to leakage ratios for the plurality of a sectors, determining the first set of DHM values including determining, for each sector of the plurality of sectors, a maximum of an inverse Fourier transform a product of a Fourier transform of the reference signals and a Fourier transform of the feedback signals. In some embodiments, the process includes determining a power for each sector of the plurality of sectors based at least in part on the determined maximum for each sector of the plurality of sectors. In some embodiments, the process includes determining the first set of DHM values by selecting a set of phase values that produce the first set of optimal leakage ratios, the first set of phase values being selected from a range of phase values. Having described the general process flow of arrangements of the disclosure and having provided examples of hardware and software arrangements for implementing the processes and functions of the disclosure, the sections below provide details and examples of arrangements for signal to leakage ratio optimization (SLRO) for analog hybrid matrix (AHM) sector power. FIG. 8 is a block diagram of an example of a multi-sector radio configured according to principles disclosed herein. The multi-sector radio 58 includes a DHM 94 for each of a plurality of carrier frequencies. Although only two DHMs 94 are shown, there may be more than two carrier frequencies and more than two DHMs 94. A DHM 94 operates to distribute power in the sector input signals to a plurality of transmit chains 96 . Each transmit chain may nominally handle about 1 / 3 of the power of a signal for each sector. In the general case there may be at least as many transmit chains as there are sectors but there could be more. Also there could be 2 or more sectors where three is only one example. In some embodiments, there may be configured an equalizer that receives outputs from the DHMs 94 and performs equalization of power for a plurality of carriers and / or a plurality of frequency bands. Each transmit chain 96 receives a sum of signals from the DHMs 94 for all the sectors, and outputs a transmit chain output signal. Each transmit chain output signal is input to an AHM 98 distributes the power of the transmit chain output signals to product a sector output signal for each sector. In some embodiments, a filter 100 for each sector is configured to filter a respective sector output signal. A plurality of couplers 102, one for each sector, is configured to couple power from each filter sector output signal to produce feedback signals that are input to the SLRO unit 32. The SLRO unit 32 is configured to determine a leakage value for each of a plurality of frequency domain sections and for each sector based at least in part on the feedback signals and to adjust values of the digital hybrid matrix, DHM, based at least in part on the determined leakage values. FIG. 9 is a signal flow graph of an example combination of a digital hybrid matrix (DHM) 94 and an AHM 98 configured according to principles disclosed herein. Let denote an input signal for each sector, for example, ^ = 1,2,3, with sample index ^ and iteration number ^, let ^^,^,^denote the DHM 94 output transmit chain signal ^ with sample index ^, let ^^^,^,^denote the AHM 98 output sector ^ signal with sample index ^, and let ^^^,^denote DHM weights, for example, ^ = 1,2,3 for each input signal with index ^ and with DHM adjustment iteration index ^. Note that the principles disclosed herein apply to at least two sectors, are shown for three sectors by example and for more than three sectors by direct extension The DHM 94 output transmit chain signals m are: ^^,^,^= ^^^,^^^,^,^+ ^^^,^^^,^,^+ ^^^,^^^,^,^^^,^,^= ^^^,^^^,^,^+ ^^^,^^^,^,^+ ^^^,^^^,^,^or, Time alignment between transmit branches In some embodiments, the SLRO algorithm implemented by the SLRO unit 32 assumes that a power amplifier linearization algorithm will ensure equal transmit delays for all the transmit branches. Feedback signal time alignment In some embodiments, the feedback signals are time aligned with the reference signals in the SLRO unit 32. Delay estimation A delay between a reference signal and a feedback signal may be determined by the SLRO unit 32 as follows: • Pad each summed reference signal and feedback signal with ^^^zeros to perform a subsequent linear convolution in the frequency domain. The zero padding may be performed by concatenating the zeros to the end of the vectors summed input signal vector and at the end of a feedback signal vector to get the vectors ^!^,^"#$^^%and ^&^,^"#$^^% where ^^is now the time domain index of the padded signal: ^&^,^"#$^′% = ()^(*+$^^,^,^. / 0)^1^^^2% • Take the FFT of ^!^,^"#$^^%and ^&^,^"#$^^%: 3!^$4% = 556$^!^,^"#$^^%) 3&^$4% = 556$^!^,^"#$^^%) • Perform a time interpolation with 7^by padding the frequency domain by ^^"#= 12 ∗ ^^^2 • Perform a cross correlation of ^!and ^&using the fast convolution follows: =>?@@= 556^A^BC$^55613!^,^"#∗ ()^D$3&^,^"#2%% o It is noted that FFT shift is a standard operation to swap the first and second half of the samples so that first sample component will be at the center; • Determine the absolute value of a maximum of the cross correlation and the index where the maximum occurs. This gives a fractional delay E (which is a fractional value relative to up sampling rate). The fractional delay D may be determined as follows: E = ^^^ / F$max$|yLMNN|%%− ^^"#7^− 1 Delay Compensation Once the delay E is determined, it may be applied to the entire feedback as follows: 1. Remove E samples from the upsampled feedback signal ^&to give: ^O= ^&$E, E + 1, … , E + PQ− 1) where ^&= ^^^*R^S / $^^^,^,^, 7^% and PQis the length of the upsampled feedback signal; 2. Down sample ^Oto obtain the time aligned feedback signal given by: ^^,^,^,= E)T^^*R^S / $^O, 7^% The down-sample function may be implemented by selecting every 7^samples, starting from the first sample. FIG. 10 is illustrates a graph of performance of the SLRO unit 32 during a search mode of operation (which may be employed at least during a startup interval) and an iteration mode of operation (which may be employed at least during a maintenance interval). Search Mode DHM starting weight In the search mode, a series of DHM search trials may be performed by the SLRO unit 32 to determine an initial combination of DHM phases that will give a reasonable signal to leakage ratio as a starting point for a subsequent iteration mode. The DHM value for a the ithtrial, ^ = 1,2, … , PC@^"U(with PC@^"Ubeing the number of trials), may be expressed and determined as: ^V^,^= W / XYZ[,\The magnitude W = 1 / √3. The number of trials may be the square of the number of phase steps P^A: The number of phase steps is configurable and may be set to P^A_ {3,4,5,6}. The phase increment e^^>@for each trial is: e^^>@= 360 / P^A An example of the DHM phase search pattern for P^A= 4 and with e^^>@= 90° is: e^^,^= {00000000000 0000 0} e^^,^= {000090909090180180180180270270270270} e^^,^= {090180270090180270090180270090180270 } The same pattern will be used for all three DHM groups: e^^,^= e^^,^= e^^,^e^^,^= e^^,^= e^^,^e^^,^= e^^,^= e^^,^Find the DHM set that results in the best SLR The trial pattern of phases disclosed above is implemented and using k captured values of the input signal and the corresponding k sampled AHM 98 output values, the trial DHM values that determine an initial set of signal to leakage ratios may be determined by the SLRO unit 32 as follows. A fast convolution between the sum of the input signals and each AHM output signal may be performed to get the output voltage at sector ^ as follows: where and where K is the size of the fast Fourier transform (FFT) size and w() is a window function such as a Kaiser window. Here 3>∗?no,^is the conjugate of the combined signal 3>?no,m. The maximum of the inverse FFT (IFFT) is at sample index ^ = 1 if the AHM output signals and input signals are time aligned. In some embodiments, k = 256 for each captured carrier at the baseband rate (for example 7.68Msps for a 5MHz LTE carrier). The output voltage and power for each sector may be determined as follows: Where: The index ^^for each sector where q^,^is a maximum may be determined from the PC@^"Uvalues. The best DHM phases for optimum SLRs is then selected from the DHM trial values corresponding to the index ^^. The selected DHM phase values at index ^^will then be eV,^tand the selected DHM values are: Iteration Mode As explained above, in the search mode, the set of DHM values for each signal is determined giving a reasonable SLR for the input signal at the desired output sector. This set of DHM values is used as a starting point for the iteration mode. In the iteration mode, the DHM values may be adjusted by the SLRO unit 32 to optimize the SLR for each sector as disclosed herein. In particular, the set of DHM values may be determined by the SLRO unit 32 and communicated to the DHMs 94. Each DHM 94 may be updated iteratively by the SLRO unit 32 to reduce the leakage into each sector ^ = {1,2,3} as follows: where iteration ^ + 1 is the next iteration and ^ is the current iteration. The phase slope is to compensate for the delay between transmit paths and delay in the AHM 98. In the first iteration, the DHM values ^V$^-^%,^tand corresponding output correlation voltages 7^,^tdetermined during the search mode will be used. The SLRO algorithm convergence speed may be controlled with the convergency constant z, which is set to 1 for PU"@ |number of iterations and then to a smaller value (typically). The smaller convergency constant value and PU"@ |should be adjustable to optimize algorithm performance, but initial simulations show that the small convergency constant z=0.2 and number of iterations for large convergency constant PU"@ |= 10 may be used. The DHM values may be normalized for each input signal as follows: Using the updated DHM values, the output power components for each signal are determined. This is done by correlating each sector signal with each input signal: 7^^,^v^,m= max $^^^+ $l^,^v^,m3^∗,^v^,m%% , k = 1,2, .. , k where 1,2, .. , K, k = 1,2, .. , k and 1,2, .. , k, k = 1,2, .. , k In other words, the correlation may be performed by multiplying Fourier transforms in the frequency domain. The auto and cross correlation between input signals may be determined by: The correlation between the input signals may be reduced at the output ports as follows: where 6^^,^is the transfer function between each output port of the DHM 94 and each input port of the DHM 94, determined in the previous iteration. The transfer function to be used in the next iteration is determined by: 6^^,^v^= 7^^,^v^ / s^^,^v^Phase slope for delay compensation The phase slope for delay compensation may be determined by the SLRO unit 32 as disclosed herein. The phase of the frequency domain transfer function between each AHM output signal and each DHM input signal may be determined as follows: for [^ = 1, ^ = 1],^^ = 2, ^ = 2]and^^ = 3, ^ = 3] The phase may be mapped so that DC is in the center of a frequency domain section: A linear fit may be applied to the data to give the linear curve ^^^,^v^,m. This linear fit may be performed only in a subsection of the frequency domain section. The phase correction may then be expressed and determined as follows: The correction applied to the DHM values may then be determined as (with v=p): As will be appreciated by one of skill in the art, the concepts described herein may be embodied as a method, data processing system, computer program product and / or computer storage media storing an executable computer program. Accordingly, the concepts described herein may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects all generally referred to herein as a “circuit” or “module.” Any process, step, action and / or functionality described herein may be performed by, and / or associated to, a corresponding module, which may be implemented in software and / or firmware and / or hardware. Furthermore, the disclosure may take the form of a computer program product on a tangible computer usable storage medium having computer program code embodied in the medium that may be executed by a computer. Any suitable tangible computer readable medium may be utilized including hard disks, CD-ROMs, electronic storage devices, optical storage devices, or magnetic storage devices. Some embodiments are described herein with reference to flowchart illustrations and / or block diagrams of methods, systems and computer program products. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, may be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer (to thereby create a special purpose computer), special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks. These computer program instructions may also be stored in a computer readable memory or storage medium that may direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instruction means which implement the function / act specified in the flowchart and / or block diagram block or blocks. The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks. It is to be understood that the functions / acts noted in the blocks may occur out of the order noted in the operational illustrations. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the functionality / acts involved. Although some of the diagrams include arrows on communication paths to show a primary direction of communication, it is to be understood that communication may occur in the opposite direction to the depicted arrows. Computer program code for carrying out operations of the concepts described herein may be written in an object oriented programming language such as Python, Java® or C++. However, the computer program code for carrying out operations of the disclosure may also be written in conventional procedural programming languages, such as the "C" programming language. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer. In the latter scenario, the remote computer may be connected to the user's computer through a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). Many different embodiments 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, all embodiments may be combined in any way and / or combination, and the present specification, including the drawings, shall be construed to constitute a complete written description of all combinations and subcombinations of the embodiments 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 appreciated by persons skilled in the art that the embodiments described herein are not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings without departing from the scope of the following claims.

Claims

What is claimed is:

1. A multi-sector radio (58) configured to operate in a network node and configured to communicate with a plurality of wireless devices, WDs, the multi-sector radio (58) comprising: a digital hybrid matrix, DHM (94), configured to: receive a sector input signal for each of a plurality of carriers and a plurality of sectors; and distribute power of the sector input signals to a plurality of transmit chains , each transmit chain configured to output a transmit chain output signal; an analog hybrid matrix, AHM (98), configured to receive the transmit chain output signals and to output a sector output signal for each sector; a plurality of couplers (102), one coupler (102) for each sector of the plurality of sectors, each coupler (102) configured to couple power of the sector output signal to provide a feedback signal to processing circuitry (68); and the processing circuitry (68), the processing circuitry (68) configured to receive the feedback signals and: determine a leakage value for each of a plurality of frequency domain sections and for each sector of the plurality of sectors based at least in part on the feedback signals; and adjust values of the DHM (94) based at least in part on the determined leakage values.

2. The multi-sector radio (58) of Claim 1, wherein the DHM (94) is configured to distribute power to carriers grouped in a plurality of frequency bands, and the multi-sector radio (58) includes an equalizer configured to perform equalization of power of the plurality of frequency bands.

3. The multi-sector radio (58) of any of Claims 1 and 2, wherein the DHM values are adjusted to optimize a signal to leakage ratio for each sector of the plurality of sectors.

4. The multi-sector radio (58) of Claim 3, wherein adjusting the DHM values to optimize the signal to leakage ratio for each sector of the plurality of sectors includesdetermining a set of DHM values that produces a first set of optimal signal to leakage ratios for the plurality of sectors.

5. The multi-sector radio (58) of any of Claims 1-4, wherein the DHM values are adjusted iteratively to drive the determined leakage values toward zero.

6. The multi-sector radio (58) of any of Claims 1-5, wherein updating the DHM values includes subtracting the determined leakage values from a current set of DHM values.

7. The multi-sector radio (58) of any of Claims 1-6, further comprising, for each sector output signal, a filter between the AHM (98) and the coupler (102) for the respective sector of the plurality of sectors.

8. The multi-sector radio (58) of any of Claims 1-7, wherein the processing circuitry (68) is further configured to perform a time alignment procedure to align each feedback signal with a respective reference signal.

9. The multi-sector radio (58) of Claim 8, wherein the time alignment procedure includes padding each reference signal with at least one zero and padding each feedback signal with at least one zero.

10. The multi-sector radio (58) of Claim 9, wherein the processing circuitry (68) is further configured to determine a Fourier transform of a first concatenated sum of the zero padded reference signals and to determine a Fourier transform of a second concatenated sum of the zero padded feedback signals.

11. The multi-sector radio (58) of Claim 10, wherein the processing circuitry (68) is further configured to pad the Fourier transformed first concatenated sum with at least one zero and to pad the Fourier transformed second concatenated sum with at least one zero.

12. The multi-sector radio (58) of Claim 11, wherein the processing circuitry (68) is further configured to determine a maximum of a cross correlation, the crosscorrelation being determined in the frequency domain based at least in part on a convolution of the zero padded Fourier transformed first concatenated sum and a conjugate of the zero padded Fourier transformed second concatenated sum and to determine a fractional delay based at least in part on an index of occurrence of the maximum of the cross correlation 13. The multi-sector radio (58) of Claim 12, wherein the processing circuitry (68) is further configured to apply the fractional delay to the zero padded feedback signals to obtain a time aligned feedback signal for each sector of the plurality of sectors.

14. The multi-sector radio (58) of any of Claims 9-13, wherein adjusting the DHM values includes determining a first set of DHM values that produces a first set of optimal signal to leakage ratios for the plurality of a sectors, determining the first set of DHM values including determining, for each sector of the plurality of sectors, a maximum of an inverse Fourier transform a product of a Fourier transform of the reference signals and a Fourier transform of the feedback signals.

15. The multi-sector radio (58) of Claim 14, wherein the processing circuitry (68) is further configured to determine a power for each sector of the plurality of sectors based at least in part on the determined maximum for each sector of the plurality of sectors.

16. The multi-sector radio (58) of any of Claims 14 and 15, wherein the processing circuitry (68) is further configured to determine the first set of DHM values by selecting a set of phase values that produce the first set of optimal leakage ratios, the first set of phase values being selected from a range of phase values.

17. A method in a multi-sector radio (58) configured to operate in a network node and configured to communicate with a plurality of wireless devices, WDs, the method comprising: distributing (S134) power of a plurality of sector input signals for a plurality of carriers and a plurality of sectors via a digital hybrid matrix, DHM (94), to a plurality of transmit chains, each transmit chain configured to output a transmit chain output signal;determining (S136) via an analog hybrid matrix, AHM (98), a sector output signal for each sector; coupling (S138) power of each sector output signal to provide a feedback signal for each sector to processing circuitry (68); determining (S140) a leakage value for each of a plurality of frequency domain sections and for each sector based at least in part on the feedback signals; and adjusting (S142) values of the DHM (94) based at least in part on the determined leakage values.

18. The method of Claim 17, further comprising distributing power to the plurality of carriers grouped in a plurality of frequency bands, and performing equalization of power of the plurality of frequency bands.

19. The method of any of Claims 17 and 18, wherein the DHM values are adjusted to optimize a signal to leakage ratio for each sector.

20. The method of Claim 19, wherein adjusting the DHM values to optimize the signal to leakage ratio for each sector includes determining a set of DHM values among that produces a first set of optimal signal to leakage ratios for the plurality of sectors.

21. The method of any of Claims 17-19, wherein the DHM values are adjusted iteratively to drive the determined leakage values toward zero.

22. The method of any of Claims 17-20, wherein updating the DHM values includes subtracting the determined leakage values from a current set of DHM values.

23. The method of any of Claims 17-21, further comprising filtering each sector output signal via a filter between the AHM (98) and the coupler (102) for the respective sector of the plurality of sectors.

24. The method of any of Claims 17-22, further comprising performing a time alignment procedure to align each feedback signal with a respective reference signal.

25. The method of Claim 24, wherein the time alignment procedure includes padding each reference signal with at least one zero and padding each feedback signal with at least one zero.

26. The method of Claim 25, further comprising determining a Fourier transform of a first concatenated sum of the zero padded reference signals and determining a Fourier transform of a second concatenated sum of the zero padded feedback signals.

27. The method of Claim 26, further comprising padding the Fourier transformed first concatenated sum with at least one zero and padding the Fourier transformed second concatenated sum with at least one zero.

28. The method of Claim 27, further comprising determining a maximum of a cross correlation, the cross correlation being determined in the frequency domain based at least in part on a convolution of the zero padded Fourier transformed first concatenated sum and a conjugate of the zero padded Fourier transformed second concatenated sum and determining a fractional delay based at least in part on an index of occurrence of the maximum of the cross correlation.

29. The method of Claim 27, further comprising applying the fractional delay to the zero padded feedback signals to obtain a time aligned feedback signal for each sector of the plurality of sectors.

30. The method of any of Claims 25-29, wherein adjusting the DHM values includes determining a first set of DHM values that produces a first set of optimal signal to leakage ratios for the plurality of a sectors, determining the first set of DHM values including determining, for each sector of the plurality of sectors, a maximum of an inverse Fourier transform a product of a Fourier transform of the reference signals and a Fourier transform of the feedback signals.

31. The method of Claim 30, further comprising determining a power for each sector of the plurality of sectors based at least in part on the determined maximum for each sector of the plurality of sectors.

32. The method of any of Claims 30 and 31, further comprising determining the first set of DHM values by selecting a set of phase values that produce the first set of optimal leakage ratios, the first set of phase values being selected from a range of phase values.

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