WO2015043829A1

WO2015043829A1 - Network element, radio frequency mast-top module and methods therefor

Info

Publication number: WO2015043829A1
Application number: PCT/EP2014/067484
Authority: WO
Inventors: Conor O'keeffe; Joe Moore
Original assignee: Socowave Technologies Limited
Priority date: 2013-09-26
Filing date: 2014-08-15
Publication date: 2015-04-02
Also published as: GB201317117D0; GB2519287A

Abstract

A network element (MBCU) for a mast-top installation comprising a baseband converter module comprising at least one data interface and at least one microprocessor operably coupled to the at least one data interface and arranged to configure signals within the network element. Wherein the baseband converter module further comprises or is operably coupled to at least one radio frequency mast-top docking station, electrically coupled to the at least one data interface and for physically receiving a corresponding at least one removable radio frequency mast-top module comprising a memory that stores data to allow determination of at least one configuration of the at least one removable radio frequency mast-top module and wherein the at least one microprocessor is arranged to interrogate the memory of a docked at least one removable radio frequency mast-top module via the at least one radio frequency mast-top docking station to determine the at least one configuration thereof and interoperate therewith. A radio frequency mast-top module and associated methods are also described.

Description

NETWORK ELEMENT, RADIO FREQUENCY MAST-TOP MODULE AND METHODS THEREFOR Field of the invention The field of the invention relates to a network element and a radio frequency mast-top module for an antenna arrangement and methods of communication between modules of the antenna arrangement. In particular, the field of the invention relates to a modular based communication unit or an antenna arrangement. Background of the Invention

Currently, original equipment manufacturer (OEM) vendors of network infrastructure equipment are overwhelmed with the number of variants required to service the market place. This is exacerbated by the sheer number of frequency bands to be supported globally (currently forty three 3GPP™ bands require supporting). Furthermore, there is an increased range of product types required to support new types of cells (e.g. femto, pico, micro, macro) as well as a larger range of power levels and air interface protocols (e.g. GSM, 3G, HSPA, LTE-FDD and LTE-A). Further, the evolution of standard base stations to encompass remote radio heads (RRH) and active antenna systems (AAS) adds even more variants. As each product variant is generally required to undergo baseband interoperability conformance testing, it may be advantageous to standardise elements of the radio access network, thereby potentially reducing the amount of testing required, thereby enabling easier management of product variants and new product introduction cycle times.

In addition to the variety of products on offer, network operators generally require network equipment to be serviceable, particularly equipment that is located in difficult to access locations. Network equipment deployed in the field should have a mean time between failures (MTBF) of fifteen years. This requirement has become increasingly challenging to meet for systems that incorporate electronics within the antenna system.

In the case of active antenna systems (AAS), there are some single points of failure that could potentially disable the entire system. These could include power supply modules and communications links comprised within the AAS. Accessibility to these failure points is critical if the network element is to be deemed serviceable in the field, without the need to replace the complete unit. Removing the entirety of the network equipment is a burdensome task on the network operator. Therefore, it may be advantageous to provide a means for removing critical electronics from the network equipment, for example an AAS, without removing the AAS from its tower top location in the field.

Generally, installation of tower top equipment is governed by various health and safety regulations. In the UK, installation of tower top equipment above 26kg cannot be performed manually, which therefore requires the use of expensive mechanical cranes to hoist the equipment into position. This can add a significant cost to the overall installation cost of AAS or RRH systems if they exceed the above mentioned weight limit. Therefore, it may be advantageous to provide a system that meets the above mentioned weight requirement, potentially allowing for a cheaper manual installation. Currently, AAS and RRH network elements comprise semiconductor elements that have differing operating temperature limits. Typically, industrial grade digital signal processing (DSP) devices operate to around 85°C, while power amplifier modules may be required to operate to temperatures in excess of 100Ό. These differences in operating temperatures can lead to issues when positioning components within the AAS and RRH network elements. In some cases, it may be advantageous to physically separate some of these devices in order to facilitate improved thermal management and enhance reliability of AAS and RRH network elements.

Currently, network operators need to support multiple frequency bands at the same time and, often, at the same site. This is achieved by including a plurality of RRH devices at the same site, which are operably coupled via coaxial feeder outputs to multiple antenna devices. This means that for each new frequency band, a new RRH may be deployed with its associated power amplifier and duplexer tuned to this new frequency band. In some cases, it may be advantageous to provide a system that can be easily adapted and updated so that it may be able to support these new frequency bands, as and when the antenna site needs to support them.

Tower site owners generally charge network operators to install network equipment on their tower sites, and this charge is generally calculated on the amount of installed equipment on a tower. As discussed previously, a plurality of RRH devices may be deployed on any one tower site in order to support multiple frequency bands. Thus, each new RRH device will, however, increase charges to network operators. Therefore, in some cases, it may be advantageous to limit the number of RRH devices installed on a particular tower site, whilst still supporting multiple frequency bands.

Network equipment installed around ten years ago for 3G may now need replacing or upgrading in order for network operators to support LTE. This process can be expensive, as most of the current network equipment may not be able to support new frequency bands and air interface protocols required to support LTE. Therefore, it may be beneficial to provide a system that can be easily upgraded, thereby potentially reducing total cost of ownership to network providers.

Referring to FIG. 1 of WO2012103821 A3, a modular active antenna system is illustrated comprising a fixed unit 11 and at least two removable active units 12a, 12b. This patent application suggests that after initial installation, if it is discovered that different antenna combinations are required, such as single band, dual-band and multi-frequency, an appropriate combination of active units 12a, 12b can be chosen or inserted without having to remove fixed unit 11 . If an active unit 12a, 12b fails, the active unit can simply be replaced without disassembling the fixed unit.

Thus, a need exists for improved communication units/network elements and methods for an antenna system. Summary of the Invention

Accordingly, the invention seeks to mitigate, alleviate or eliminate one or more of the above mentioned disadvantages, either singly or in any combination.

According to a first aspect, a network element (MBCU) for a mast-top installation comprises a baseband converter module comprising: at least one data interface; and at least one microprocessor operably coupled to the at least one data interface and arranged to configure signals within the network element. The baseband converter module further comprises or is operably coupled to at least one radio frequency mast-top docking station, electrically coupled to the at least one data interface and for physically receiving a corresponding at least one removable radio frequency mast-top module comprising a memory that stores data to allow determination of at least one configuration of the at least one removable radio frequency mast-top module; and the at least one microprocessor is arranged to interrogate the memory of a docked at least one removable radio frequency mast-top module via the at least one radio frequency mast-top docking station to determine the at least one configuration thereof and interoperate therewith.

In one optional example, the baseband converter module may further comprise at least one frequency conversion module operably coupled to the at least one microprocessor and arranged to perform at least one of: up-convert baseband data signals to radio frequency signals received from the at least one microprocessor for passing to a docked at least one removable radio frequency mast-top module via the at least one data interface; and down-convert radio frequency signals to baseband data signals received from a docked at least one removable radio frequency mast-top module via the at least one data interface for passing to the at least one microprocessor, which may be at least one digital signal processor.

In one optional example, the network element may be substantially frequency band agnostic and a plurality of radio frequency mast-top docking stations receive a plurality of removable radio frequency mast-top modules to support a plurality of different frequency bands of operation.

In one optional example, the at least one microprocessor may be programmable via the at least one radio frequency mast-top docking station memory interface port.

In one optional example, the at least one microprocessor may be configured to program the at least one removable radio frequency mast-top module via the at least one radio frequency mast-top docking station memory interface port.

In one optional example, the at least one microprocessor may be arranged to interrogate the memory and to identify the docked at least one removable radio frequency mast-top module.

In one optional example, the at least one microprocessor may be arranged to interrogate the memory and to determine one or more of the following parameters of the at least one removable radio frequency mast-top module: a serial number, a model number, an array dimension, an address table for selecting each antenna element of the array for transmit and receive operation, one or more frequency bands supported mapping of transmit or receive paths in use, an output power capability, one or more calibration parameters for a feedback circuit, a digital predistortion setting, antenna array configuration mapping, a date of manufacture, final production test data, a manufacturer code, a memory interface configuration format.

In one optional example, the at least one microprocessor may be arranged to interrogate the memory of the at least one removable radio frequency mast-top module and determine at least one configuration parameter by at least one from a group of: searching a database locatable on the signal processing module, or when operating in a remote location accessible though at least one backhaul interface using the interrogated memory information. In one optional example, the at least one microprocessor may be arranged to interrogate the memory of the docked removable radio frequency mast-top module to determine a capability of a combined network element comprising at least the baseband converter module and the at least one removable docked radio frequency mast-top module.

In one optional example, the baseband converter module may further comprise a backhaul interface operably coupled to the at least one microprocessor to establish a connection with a core network after the at least one microprocessor interrogates the memory of and in response thereto configure at least one of: the baseband converter module, at least one removable radio frequency mast-top module via the at least one radio frequency mast-top docking station.

In one optional example, the at least one microprocessor may be arranged to operate the at least one removable docked radio frequency mast-top module in at least one of: an output power thereof, at least one antenna beam setting, a carrier frequency, at least one beam-tilt angle, an air- interface protocol, band selection of one or more radio frequency circuits.

In a second aspect of the invention, a method for operating a network element (MBCU) for a mast-top installation comprising a baseband converter module comprising at least one data interface; and at least one microprocessor operably coupled to the at least one data interface and arranged to configure signals within the network element is described. The method comprises at the network element: physically receiving a corresponding at least one removable radio frequency mast-top module comprising a memory; electrically coupling the baseband converter module to at least one radio frequency mast-top docking station; electrically coupling the baseband converter module to the at least one data interface; interrogating the memory to determine at least one configuration of a docked at least one removable radio frequency mast-top module from via the at least one radio frequency mast-top docking station ; and interoperating with the docked at least one removable radio frequency mast-top module via the at least one radio frequency mast-top docking station.

In a third aspect of the invention, a non-transitory computer program product comprising executable program code for operating a network element (MBCU) for a mast-top installation is described, the executable program code operable for, when executed at a communication unit, performing the method of the second aspect.

In a fourth aspect of the invention, a radio frequency mast-top module (dockable DRFU) for a mast-top installation comprises: a plurality of band-specific radio frequency components; an interface for removably physically locating the radio frequency mast-top module in, and electrically coupling to, at least one radio frequency mast-top docking station for routing radio frequency signals there through ; and a memory that stores configuration data of the at least one removable radio frequency mast-top module. The memory of the radio frequency mast-top module, when docked in the at least one radio frequency mast-top docking station, is arranged to be interrogated to allow determination of at least one configuration of the radio frequency mast-top module in order for the plurality of band-specific radio frequency components to interoperate with the at least one radio frequency mast-top docking station. In one optional example, the radio frequency mast-top module may be at least part of a remote radio head and comprises at least one external connector for coupling at least one RF signal to at least one antenna.

In one optional example, the radio frequency mast-top module may be at least part of an active antenna system (AAS) or antenna integrated radio and comprises a plurality of antenna element coupled to the plurality of band-specific radio frequency components.

In one optional example, the plurality of band-specific radio frequency components may comprise a plurality of duplex filters.

In one optional example, the interface may be operably coupled to at least one RF switch to select and route for at least one coupled portion of at least one signal to or from an antenna element feed to support beamforming calibration.

In one optional example, the interface may be operably coupled to route for at least one coupled portion of at least one signal from an antenna feed to support at least one of: power amplifier predistortion measurements, power amplifier predistortion feedback signals.

In one optional example, the radio frequency mast-top module may further comprise a plurality of switches operably coupled to a plurality of antenna elements via a switched feedback circuit, wherein the interface is operably coupled to at least one switch arranged to provide a feedback signal via the switched feedback circuit.

In one optional example, the interface may comprise at least one port to support diagnostic operations run on interface signals passing therethrough.

In one optional example, the interface may comprise at least one port to support software configurability of feedback networks.

In one optional example, the interface may be operably coupled to the memory and, when docked in the at least one radio frequency mast-top docking station, may be arranged to be interrogated to identify at least one of: a configuration status, a build date, a serial number, one or more calibration parameters.

In a fifth aspect of the invention, a method for operating a removable radio frequency mast-top module (dockable DRFU) for a mast-top installation comprising a memory and a plurality of band- specific radio frequency components is described. The method comprises, at the removable radio frequency mast-top module, storing configuration data of the removable radio frequency mast-top module; physically and electrically coupling the removable radio frequency mast-top module to a baseband converter module via at least one radio frequency mast-top docking station; receiving a memory interrogation to determine at least one configuration of the removable radio frequency mast- top module from the baseband converter module via the at least one radio frequency mast-top docking station and forwarding at least one configuration data to the baseband converter module; and interoperating with the baseband converter module via the at least one radio frequency mast-top docking station.

In a sixth aspect of the invention, a non-transitory computer program product comprises executable program code for operating a removable radio frequency mast-top module, the executable program code operable for, when executed at a communication unit, performing the method of fourth aspect.

Brief Description of the Drawings

Embodiments of the invention will be described, by way of example only, with reference to the accompanying drawings, in which

FIG. 1 illustrates a known antenna unit.

FIG. 2 illustrates an example of a modular antenna system according to aspects of the invention.

FIG. 3 illustrates a simplified example of a masthead baseband converter unit (MBCU) according to aspects of the invention.

FIG. 4 illustrates simplified examples of possible antenna systems that implement aspects of the invention.

FIG. 5 illustrates a simplified block diagram of the modular active antenna system of FIG. 4 according to aspects of the invention.

FIG. 6 illustrates a simplified flow diagram of an MBCU procedure according to aspects of the invention.

FIG. 7 illustrates a simplified block diagram of the modular remote radio head antenna system of FIG. 4 according to aspects of the invention.

FIG. 8 illustrates a simplified block diagram of the modular antenna integrated radio system of FIG. 4 according to aspects of the invention.

FIG. 9 illustrates a typical computing system that may be employed to implement signal processing functionality in embodiments of the invention.

Detailed Description of Embodiments of the Invention

Referring to FIG. 2, an example of a modular antenna system 200 is illustrated comprising, a masthead baseband converter unit (MBCU) 202, a docking station 204 and a plurality of dockable radio frequency units (DRFU) 206, 208, 210. Docking station 204 may be operable to receive one or more of the DRFUs 206, 208, 210 at any one time. In this example, each DRFU 206, 208, 210 may be a different band specific unit, which may allow the modular antenna system 200 to support multiple bands simultaneously. The docking station 204 may be operable to receive DRFUs 206, 208, 210, which may encompass passive devices, active devices, (for example active antennas), or a combination of the two (antenna integrated radio unit), in addition to the corresponding radio frequency devices and circuits. In some examples, the docking station 204 may comprise at least an interface connector containing a plurality of connection ports for connecting at least one DRFU 206, 208, 210 to at least one MBCU 202. Further, in some examples, the docking station204 may be integrated as part of either the DRFU 206, 208, 210 or as part of the MBCU 202. Each DRFU 206, 208, 210 may be operably coupled to the docking station via at least one data interface 212, which may be, for example, a multiport connector. The at least one data interface 212 may comprise a plurality of sub-interfaces 213 that may be operable to relay information from DRFUs 206, 208, 210 to docking station 204. Further, docking station 204 may be operably coupled to the MBCU 202 via a further data interface 214 and be operable to route signals from the plurality of DRFUs 206, 208 and 210 to the MBCU 202 via the further data interface 214, which may also be a multiport connector. In some examples, the data interface 214 may comprise one or more of a digital control interface, 216, distributed power interface 218, transmit radio frequency path interface 220, receive radio frequency path interface 222 and radio frequency calibration interface 224. Therefore, data interface 214 may comprise at least one sub interface operable to transmit relevant information from DRFUs 206, 208, 210 to MBCU 202.

For completeness, MBCU 202 has been illustrated with further optional connectivity, for example, baseband interface 225, Ethernet interface 226 and power interface 228.

In some examples, modular antenna system 200 may be operable to allow standardisation of elements of the radio access network, allow for easier access to critical electronics, reduce weight, improve thermal management and allow for the modular antenna system 200 to be upgraded easily when compared to the prior art.

Referring to FIG. 3, an example of an MBCU 300 is illustrated, according to some example embodiments of the invention. In one example, MBCU 300 may be implemented as the MBCU 202 of FIG. 2, in which case it may comprise at least one data interface to docking station 204.

In another example, the MBCU 300 may comprise a dockable interface 302, which may be operable to couple one or more DRFUs (not shown) without the need for docking station 204. The dockable interface 302 may comprise one or more connectors, for example connectors 304, 306, 308, 310, 312. Connector 304 may operably coupled to power management module 314, connector 306 may be operably coupled to an up-conversion module 316 of a radio transceiver module 320, connector 308 may be operably coupled to a down-conversion module 31 8 of the radio transceiver module 320, connector 310 may be operably coupled to a radio frequency calibration transceiver module 322, and connector 312 may be operably coupled to a microprocessor 324 via, for example a digital bus 323 interface. Digital bus 323 may be a universal serial bus (USB) or a serial peripheral interface (SPI™) bus. Digital bus 323 may be utilised to read memory files/pages from a docked DRFU, thereby enabling configuration options to be determined by MBCU 300. In some examples, the memory bus connector may couple signals by either electrical or optical means.

Connectors 304, 306, 308, 31 0, 312 may be single or multi-port connectors and, may facilitate coupling between docked DRFU (not shown) and respective radio frequency elements coupled thereto.

It should be noted that MBCU 300 may comprise more than one radio transceiver module 320 and, therefore, connectors 306, 308 may be operable to couple more than one up-conversion module 316 and down conversion module 318 to at least one docked DRFU (not shown). In this example, up- conversion module 316 may be operable to perform a translation of frequencies from baseband to radio frequencies. Baseband frequencies generally are those of frequencies directly processable in the Nyquist region of either an analog to digital converter (ADC) or digital to analog converter (DAC) (often below 500MHz) and usually in Cartesian in-phase and quadrature format (T and 'Q'). Generally, radio frequencies are those utilised by the spectrum band of interest over an air interface supported by network elements. Conversely, down-conversion module 318 may be operable to perform a translation of radio frequency signals that have often been received from an antenna element, to a desired baseband frequency.

Microprocessor 324 may be operably coupled to a memory 326, which may comprise a database of configuration parameters that may be utilised to configure one or more DRFUs that are operably coupled to dockable interface 302. In some other examples, microprocessor 324 may search for configuration parameters that may be utilised to configure one or more docked DRFUs in a remote location that may be accessible through at least one backhaul interface. Backhaul interface may be an Ethernet interface 328 or backhaul optical interface 330, for example a common public radio interface (CPRI). In some examples, backhaul interface 332 may allow the MBCU 300 to be disconnected from one or more backhaul links 328, 330. Backhaul interface 332 may further comprise a backhaul DC feed 334 to power management module 314.

For the purposes of example embodiments described herein, microprocessor 324 may be any solid-state electronic circuit that may be operable to process instructions, for example executing a sequence of events such as, for example, reading a memory of a DRFU .

In an example mode of operation, MBCU 300 may facilitate coupling between a plurality of docked DRFUs (not shown) via dockable interface 302 to backhaul connections to, for example, a base station (not shown) located distal from the tower top mast. Connector 306 may transmit a plurality of output signals from radio frequency up-conversion module(s) 316 to at least one power amplifier input within one or more docked DRFU. Further, connector 308 may receive signals from one or more docked DRFU, which may have been transmitted via at least one band select front end filter and an optional low noise amplifier, and forward these onto radio frequency down-conversion module(s) 318.

In some examples, connector 310 may be operable to feedback signals to and from a docked DRFU to the calibration transceiver 322. Therefore, connector 310 may be utilised to feedback a coupled portion of a signal from an output of a power amplifier, within a docked DRFU, for the purpose of, say, calculating digital pre-distortion (DPD) coefficients, which may be utilised for improving linearity of a transmitter of the docked DRFU.

Further, connector 31 0 may be utilised to feedback a coupled portion of a power amplifier output transmit signal, thereby allowing MBCU 300 to regulate the transmit radio frequency power of one or more attached DRFU modules, which may relate to up-conversion module 316. The coupled portion of a power amplifier transmit signal could be further utilised to support DPD algorithms run on the MBCU 300, for example for each docked DRFU, thereby allowing linearization of the transfer function of the entire transmitter including the power amplifier in question. In this mode of operation, the calibration transceiver 322 may output a digitised signal that may be used by DPD algorithms to estimate correction coefficients, so as to substantially linearize the transfer function of ideal digital signal inputs to the transmitter, with those being output from the power amplifier in question.

In an example, the connector 310 may be utilised, for example in an AAS mode, to allow transmit array beamforming calibration feedback. Further, connector 310 may also be used for receive array beamforming calibration. Array beamforming calibration ensures that digital beamweight settings for each beam are not corrupted by variations by for example in receive mode, receiver to receiver amplitude, phase and latency transfer functions of the plurality of receivers. This variation of transfer functions are down to the manufacturing tolerances and environmental effects such as temperature within down-conversion module 318, for example. In this mode of operation a signal generated on the calibration transceiver 322 may be coupled to each receiver in turn of a plurality of receivers as part of the estimation of individual receiver transfer functions. .

It should be noted that although dockable interface 302 has been illustrated with a plurality of connectors 304, 306, 308, 31 0, 312, which may or may not have multi-port connections, these connectors 304, 306, 308, 310, 312 may be ganged together in a single connector. Alternatively, connectors 304, 306, 308, 310, 312 may have a one-to-one correlation with interface signals from corresponding docked DRFUs (not shown). Further, depending on applications, dockable interface 302 may comprise more or less connectors than currently illustrated in FIG. 3.

Referring to FIG. 4, simplified examples of possible antenna systems that may implement aspects of the invention are shown. FIG. 4 includes an example of a modular active antenna system 400, an example of a modular passive antenna system 440, and an example of a modular antenna integrated radio system 470.

In some examples, at least elements 410, 402, 454, 473, 472, 480, may be installed on a mast- top. A mast-top may refer to an installation point of the antenna systems 400, 440, 470.

Network operators wishing to install antenna systems 400, 454, 470 on a mast top may require at least elements 410, 454, 480 to be positioned on a mast top so that these elements are in a position to receive and transmit signals to and from a geographic coverage region, for example. This could be, for example, a telecoms installation tower wherein at least the elements41 0, 402, 454, 473, 472, 480 may be installed at, for example, 40m above ground level. In some further examples, elements 410, 402, 454, 473, 472, 480 may be installed on one or more roof top locations, for example, on buildings, building facades, and chapel steeples, Further, elements 410, 402, 454, 473, 472, 480 may be attached to street furniture and street lighting posts.

Modular active antenna system 400 may comprise an MBCU network element 402 operably coupled to a baseband processor module 404 via, say, a CPRI interface 406, and a DC supply 408. MBCU network element 402 may be operably coupled to a removable modular active antenna 41 0 via a docking module/interface 412. In this example, MBCU network element 402 may comprise critical electronic components, for example, radio frequency up-conversion and down-conversion circuits, digital signal processing modules and power management modules. Removable modular active antenna 410 may comprise less critically important components, for example, antennas, radio frequency switches, duplexers, power amplifiers, radio frequency filters and linear noise amplifiers, etc. Critical components may comprise components that are essential for the basic operation of the antenna systems 400, 440, 470. For example, components that are essential for call processing, for example include the SFP+ backhaul optical interface transducer module, the power management functions, the DSP processing device. If any of these components fail the network element may be deemed Out of service'. Less critical components may comprise, for example, individual power amplifiers, wherein if such a component fails, the entire antenna system 400, 440,470 is not completely disabled. However, performance may be degraded compared to that when fully operational. In this example, single point of failure components may be contained within the MBCU network elements 402, 442, 472.

Modular passive antenna system 440 comprises an MBCU network element 442 operably coupled to a baseband processor module 444 via, say, a CPRI interface 446, and a DC supply 448. MBCU network element 442 may be operably coupled to a removable modular remote radio head 450 via a docking module/interface 452. Further, RRH 450 may be operably coupled to at least one passive antenna unit 454. Similarly, to the above mentioned example, MBCU network element 442 may comprise critical electronic baseband components and circuits, whereas the RRH may comprise less system-critical and frequency band dependent radio frequency electronic components and circuits.

Modular antenna integrated radio system 470 may be a hybrid between modular passive antenna system 440 and modular active antenna system 400. In this example, modular integrated radio system 470 comprises an MBCU network element 472 operably coupled to a baseband processor module 474 via, say, a CPRI interface 476, and a DC supply 478. MBCU network element 472 may be operably coupled to a removable modular RRH 473, situated within a passive antenna 480, via a docking module/interface 482. In this example, RRH 473 electronics may be integrated within the radome housing of antenna 480. Visually, the modular antenna integrated radio system 470 may appear similar to modular active antenna system 400. However, the modular antenna integrated radio system 470 may not implement beamforming techniques common to active antenna systems. For example, there may not be an individual transceiver for each antenna element, but rather a single transceiver for a column of elements of common polarisation. Therefore, beamforming may rely on passive electromechanical techniques from a network of feed cables coming from an electromechanical phase shifter, whose input signal may be split from a common source from an output of a duplex filter, for example.

The above mentioned examples illustrated in FIG. 4 may provide a modular antenna system that may be operable to solve one or more of the previously discussed potential technical problems within the prior art. For example, as discussed above, a modular antenna system may allow partitioning of critical and less critical components. Situating critical components within an MBCU may have an advantage of allowing quicker, cheaper and easier replacement of critical components that may have failed within the MBCU , as the entire antenna system may not have to be removed from its mast top position. Further, a modular antenna system may allow constituent parts of the antenna system to be installed separately. This may have an advantage of reducing the total weight of each constituent part, so that a less expensive manual installation may be performed. Furthermore, separating components into a modular system may have an advantage of allowing components with a similar operating temperature to be grouped together. In this manner, thermal management of a modular antenna system may be advantageously improved. Finally, a modular antenna system may allow for improved upgradability, by having a range of DRFUs that can be replaced and/or upgraded. This may have an advantage of providing a system that can be easily and inexpensively adapted and upgraded so that it may support latest and future functionality and frequency bands, for example.

Referring to FIG. 5, a simplified block diagram of the modular active antenna system 400 of FIG. 4 is illustrated, comprising MBCU 500 and DRFU 550. In this example, DRFU 550 may be operably coupled to MBCU 500 via either a separate docking station, for example docking station 204, or a docking interface, for example dockable interface 302. However, for simplicity, connections between MBCU 500 and DRFU 550 have been shown with generic connections, denoted within hashed box 561 , so as not to overly complicate FIG. 5.

MBCU 500 may comprise at least one radio transceiver module 502, operably coupled to a DSP module 504, a calibration transceiver module 506 operably coupled to DSP module 504 and a power management module 508. The at least one radio transceiver module 502 may comprise a radio frequency up-conversion module 51 0, and a radio frequency down-conversion module 512. The radio frequency up-conversion module 510 may comprise at least digital to analog converters, low pass filters, and up-mixer circuitry. The radio frequency down-conversion module 512 may comprise at least down-conversion circuitry, low pass filters and analog to digital converters.

Further, MBCU 500 may comprise a microprocessor 520 operably coupled to switch control interface 522 and an internal memory 524 operably coupled to microprocessor 520. In some examples, microprocessor 520 may be operable to interrogate a memory 558 within docked DRFU 550. By interrogating DRFU memory 558, the microprocessor 520 may determine configuration information required to fully integrate DRFU 550 into the MBCU 500.

In this example, the at least one radio frequency up conversion module 510 may transmit a signal via docking station/interface 561 to an input of docked DRFU 550, which may be an active antenna module. At least one power amplifier module 552 may receive the transmitted signal before outputting the transmitted signal into a duplexer 554.

During a transmit phase of the DRFU 550, the duplexer 554 may selectively output the transmitted signal onto a selectable antenna element feed 556, which may be operably coupled to an antenna arrangement 564. A portion of the transmitted signal on the antenna element feed 556 may be coupled, via coupling element 555 and radio frequency switch matrix 560, to the calibration transceiver 506, via docking station/interface 561 . Radio frequency switch matrix 560 may be controlled, via switch control interface 522, to selectively couple transmitted or received signals from one or more antenna element feeds 556. In some examples, memory 558 may be operably coupled to switch control interface 522. Memory 558 may be a non-volatile memory component that may comprise stored information identifying the docked DRFU 550 and enable it to be correctly identified by MBCU 500. This stored information may be applied to memory 558 during DRFU manufacture. Further, the stored information may be re-loaded during or after docking DRFU 550 with MBCU 500. In some examples, calibration transceiver 506 may receive beamforming calibration information from one or more antenna element feed(s) 556, via coupling element 555, RF switch matrix 560 and docking station/interface 561 . Further, the calibration transceiver 506 may compare received information with a reference value in order to determine a transfer function of individual transmitters within up-conversion module 510, for example. The determined transfer function may be further utilised to equalise the amplitude, phase and latency transfer functions of a plurality of transmitters within a plurality of up-conversion modules, for example. An advantage of array calibration utilising calibration transceiver 506 may be that digital beamweights for each transmitter within up-conversion modules are maintained at antenna element 564.

Further, in some examples, calibration transceiver may be utilised for receive array beamforming calibration. In this mode of operation a signal generated on the calibration transceiver 322 may be coupled to each receiver in turn of a plurality of receivers within down-conversion module(s) 318. Therefore, a transfer function can be determined from, for example, antenna element feed 556 to its operably coupled digital beamformer. All transfer functions from antenna elements to receive beamformers may be substantially equalised so that the receive beams are performing according to that configured.

During a receive phase of the DRFU 550, the antenna arrangement 564 may receive a received signal, and forward to duplexer 554 via antenna element feed 556. A portion of the received signal may allow a coupled signal to be added, via coupling element 555, to the radio frequency switch matrix 560. The radio frequency switch matrix 560 may be controlled via switch control interface 522, and may be operable to relay the coupled portion of the received signal to the calibration transceiver 506 via docking station/interface 561 . The duplexer 554 may selectively output the received signal to a low noise amplifier 570, and an optional filter 572, before being received at radio frequency down- conversion module 512 via docking station/interface 561 .

In some examples, microprocessor 520 may interrogate DRFU's 550 memory 558 as soon as the DRFU, 550 has docked with MBCU, 500. The microprocessor 520 may interrogate memory 558 via switch control interface 522 to determine configuration data to allow the MBCU 500 to integrate docked DRFU 550 into its system. A Serial Peripheral Interface (SPI™) may be used to select a radio frequency coupled signal presented to the calibration transceiver 506. The same SPI™, or signals forming part thereof, may also be used to access memory 558. The process of interrogating memory 558 may include at least a read or an attempt to read a memory location within memory 558. In some examples, Interrogation may further include detection of and determination of a memory type of memory 558.

In some other examples, microprocessor 520 may interrogate DRFU 550 after a predetermined amount of time after the DRFU 550 has docked with the MBCU 500. In yet further examples, the DRFU 550 may trigger the microprocessor module 520 to begin interrogation. Docking

station/Interface 561 may include interfaces/modules between signals that are least sensitive to major system specifications. For example, transmit signals from radio frequency up-conversion module 510 may be low power radio frequency signals, typically no more than a few mill-watts. Therefore, any losses experienced at docking station/interface 561 may be insignificant, and have little bearing on the efficiency of transmit circuitry. Further, as the low noise amplifier 570 is within DRFU module 550, in this example, then any losses induced at docking station/interface 561 may have a minimal impact on the overall noise figure of the receiver, as governed by the Friis transmission equation.

In some examples, low noise amplifier 570 may be situated within MBCU 500. Therefore, filter 572, which may be a band pass filter, may not be required within DRFU 550. Therefore, DRFU 550 may be operable to be optimised over a wide bandwidth.

Providing a modular DRFU 550 and MBCU network interface 500, may allow for circuits that influence the radio frequency band of spectrum operation and the radio frequency transmitted output power can be contained within DRFU 550. Since most transceiver integrated circuits for cellular processing are designed to operate from 700MHz to 2.7GHz, the MBCU 500 may be designed to be substantially band agnostic.

As more and more cellular bands are being defined, some may fall outside generally accepted frequency ranges. Therefore, commercially available band agnostic broadband circuits may not be designed to operate at these frequencies. For example, some WiMax™ services are now being deployed at about 3.5GHz, thus band agnostic commercially available hardware covering 3GPP™ bands from 700MHz to 2.7GHz may not operate in this region.

In some examples, it may be advantageous to provide a substantially band agnostic antenna system, wherein substantially band agnostic refers to circuits that operate to cover a plurality of band spectrum occupancy but may not be comprehensive enough to cover all possible spectrum occupancy of transmitters or receivers that may be possible to be deployed in present or possible future band deployments.

Therefore, the MBCU 500 may be operable to receive different DRFUs 550 with different frequencies of operation without any specific hardware upgrade being required. For example, as most band specific processing is software or firmware configurable, the DSPs 504 air interface could be utilised to receive software or firmware upgrades.

Power amplifiers 552 are routinely optimised to improve efficiency as they have a significant bearing on heat generation and running costs of wireless networks. Further, these power amplifiers 552 tend to be optimally tuned for the band of operation. Likewise, duplex filters 554 are generally optimised based on transmit output power being processed, the band of operation, and noise rejection specified by network operators.

Therefore, by providing a modular system, wherein some or all of the routinely optimised electronics are provided in a DRFU 550, may allow for a system that can be routinely upgraded and optimised on a per region, operator or market basis, without having to disassemble or re-characterise the entire system.

Explanation of transmit and receive functionality with respect to FIG. 5 has been described for one antenna element feed 556 for simplicity purposes. It should be noted that the operation of DRFU 550 and MBCU 500 may operate with a plurality of receive and transmit signals on a plurality of antenna element feeds and antenna arrangements.

In the example of FIG. 5, memory 558, which may be a non volatile memory component, may comprise one or more of the following stored information elements: Serial number, model number and array dimensions (amount of elements and configuration in rows columns, polarisations and spacing between elements). The array dimension information may be used by an MBCU 500 based algorithm to calculate beam coefficients used for receive and transmit beams. The serial number and model number information may be used to index and determine configuration information of a remote database of information or from a database present on the MBCU 500, for example memory 524.

Stored information may comprise an address table, allowing a selection of each element of the array for transmit and receive operation (e.g. Antenna element 0 is addressable on value FF hex). The stored information may further comprise one or more frequency band(s) supported, a power output capability of power amplifier(s) contained therein, calibration parameters for feedback circuits and digital predistortion (DPD) algorithm optimisation routines/programs. The calibration parameters for feedback circuits may be used to determine any amplitude or phase offsets induced on signals from coupling element 555 to an interface feedback port. These calibration parameters for feedback circuits may allow for this information to be considered when determining correction coefficients in the MBCU 500, for example, for regulating output power, DPD calculations and beamform array calibration corrections.

When referring to DPD algorithm optimisations, information may be stored to allow configuration of the algorithm implemented on the MBCU 500 and one or more power amplifiers. In some examples, depending on the degree of correction required, this may encompass optimisations to a generic DPD algorithm. These could be, for example, the order of polynomials describing non-linearity for optimum DPD correction, the number (if any) of memory effect corrections required, or for example any seed values for a DPD actuator so that power amplifiers 552 may be close to a linear position starting point.

In some examples, other information parameters such as date of manufacture, final test production test data, and configuration of the memory space may also be used.

In some examples, a manufacturer code may also be added that may facilitate quality control aspects of the modular antenna system and allow for product recall, or corrections thereafter to be part of the configuration the modular antenna system.

In some examples, the configuration of the memory space may also be stored. For example non-predistortion embodiments will not require DPD algorithms to be run. Thus, in this example all field or memory allocations need not be populated. The configuration of the memory field may be updated to reflect this lack of DPD algorithms.

Referring now to FIG. 6, a simplified example of an MBCU procedure 600 is illustrated, according to example embodiments of the invention. Initially, at 602, a DRFU is docked to the MBCU's docking station/interface. In some examples, the docking interface/station may comprise a serial peripheral interface, SPI™. Alternatively, the docking station/interface may comprise a universal serial bus (USB), Double Data Rate (DDR) or Peripheral Component Interconnect Express (PCIe) interface. The interface bus may be coupled electrically or via an optical link.

The MBCU may be operable to receive a variety of DRFUs with the same or varying properties. The different varieties of DRFUs available may affect the radio frequency capability of the combined MBCU/DRFU modular system. At 604, the MBCU may be powered up via a DC power source, and at 606, the MBCU may initiate a boot sequence. In some examples, a DRFU may be docked with the MBCU while the MBCU is powered up. In this situation, the MBCU may not be transmitting at high power as this may violate many jurisdiction's health and safety regulations for installation workers pertaining to high operating electric field strengths. The boot sequence 606 may involve powering up MBCU functionality, such as microprocessors, memories, clocks and field programmable gate arrays, for example. This boot sequence may be performed on an operating system of microprocessors within the MBCU. In some examples, in subsequent power up routines, the MBCU may determine whether the docked DRFU is the same as in a previous power up. Therefore, parameters pertaining to the docked DRFU may not need to be retrieved form the DRFU or remote locations, thereby potentially, and advantageously, speeding up DRFU module configuration.

After powering up to a defined state, the MBCU may be operable to read, via one or more microprocessors one or more memories 608 of the docked DRFU to obtain, for example, information for determining a configuration of the docked DRFU . From 608, the capability of the combined network element of the DRFU and MBCU may be determined 610. Further, it may also be possible to determine 610 how the docked DRFU should be optimally configured, and if and what algorithms may be required to support, for example, DPD, beamforming setting and/or array calibration.

The determination 610 may be made by accessing specific memory field allocations or files locatable on one or more memory modules within the docket DRFU , where for example a definition of an array mapping may be located. These definitions may include, for example, serial numbers, model numbers, array dimensions, address tables for selecting an element of the docket antenna array, frequency bands, power output capabilities, calibration parameters of feedback circuits, DPD algorithm optimisations, date of manufacture, final production test data, manufacturer code, and a memory interface configuration format.

In some examples, there may be instances where not all of the required information can be determined from memory within a docked DRFU. In this example, the MBCU may be required to fetch this information from a remote memory location, for example a remote database, located in a cloud or within a location in a network operator's domain. For example, if only a model number were stored in the internal memory of a DRFU, the MBCU may have to fetch information based on this information to determine, for example, array size, feedback addresses, bands supported etc.

If, at 610, the MBCU determines that the docked DRFU is a RRH device, the MBCU may, at

612, determine mapping of transmit and receive paths in use by the docked DRFU, frequency bands supported by the docked DRFU, and output power capability of the docked DRFU . If, at 610, the MBCU determines that the docked DRFU is an AAS device, the MBCU may, at 614, at least determine array addressing configuration mapping of transmit and receive paths in use by the docked AAS, and optionally determine the frequency bands supported by the AAS, output power capability and DPD requirements of the docked AAS device. If, at 610, the MBCU determines that the docked DRFU is an Antenna Integrated Radio, the MBCU may, at 616, determine at least the mapping of transmit and receive paths in use by the docked DRFU and optionally frequency bands supported, DPD requirements and output power capabilities of the docked DRFU. Once the MBCU has determined at 610 the requirements of a docked DRFU, the MBCU may need to, at 618, connect and establish a backhaul link to at least one other network element within the corresponding core network, for example an eNodeB baseband unit 404, 444, 474 through an optical interface for example an ORI, OBSAI or CPRI interfaces 406. The establishment of this backhaul link may involve establishing physical layers of communication for transport of, for example, IQ data streams and control and management of information from an Operations and Maintenance Centre (OMC) over an optical fibre interface, for example. In some examples, the establishment of the backhaul link may be a conclusion of a negotiated IP address assignment with other network elements such as for example the eNodeB baseband unit 404, 444, 474 and or the OMC. Further, the establishment of a backhaul link may include the inclusion of the combined DRFU/MBCU device to an update registry database on a related radio network controller (RNC), so that call/data traffic can be routed there through.

In this example, establishment of a backhaul link 618 may be performed after determination of configuration 610 of the DRFU by the MBCU. In an alternative example, establishment of a backhaul link could occurs as a precursor to the determination 610. This may be necessary for examples where information pertaining to the DRFU is only locatable on a cloud or in a network operator's domain.

After the MBCU has established a backhaul link at 618, the related network may issue configuration commands so that the MBCU and DRFU are configured to the desired base station operation. This may entail, for example, setting up carrier frequencies, setting beam tilt angles, configuring air interface protocol filter settings and switching of radio frequency circuits.

At 622, the MBCU may exit its power up sequence and enter normal call processing modes of operation where radio frequency data may be processed continuously by relevant operational circuits. In this mode of operation, 622, there may be scheduled events for array calibration or DPD calibration, for example. Further, the MBCU in 622 may be operable to respond to control and command events issued by other parts of the network, such as those parts monitoring and polling for alarm conditions indicating a malfunction in the network element.

An example of a configuration command, for example, for setting channel frequency may be:-

Set CH 1 UL EARFCN= 21250 - % Sets #1 carrier frequency on UL to work on this channel no. (2.55GHz)

Set CH 1 DL EARFCN= 3250 - % Sets #1 carrier frequency on DL to work on this channel no. (2.67GHz) Referring to FIG. 7, a simplified block diagram of the modular remote radio head antenna system 440 of FIG. 4 is illustrated, comprising MBCU 700 and DRFU 750. In this example, the operation of MBCU 700 may be substantially the same as that discussed for MBCU 500 of FIG. 5. As a result, explanation of FIG. 7 will mainly focus on features that have not been previously discussed. In this example, DRFU 750 may be a remote radio head module 750, and may be operably docked to MBCU 700 via docking station/interface 760. Further, remote radio head module 750 may have a plurality of connections 780 to at least one non integrated passive antenna (not shown).

In this example, radio frequency up-conversion module 710 may transmit a signal via docking station/module 760 to an input of docked DRFU 750. At least one power amplifier module 752 may receive the transmitted signal before outputting the transmitted signal into a duplexer 756 via an antenna element feed 754. A coupling arrangement 755 may couple a portion of this transmitted signal to radio frequency switch matrix 759. The coupled portion of the transmitted signal may be passed onto a calibration transceiver within the MBCU 700. In this example, the coupling arrangement 755 may only be situated on transmit antenna element feeds.

During a transmit phase of the DRFU 750, the duplexer 756 may selectively output the transmitted signal onto a connection by means of at least one external connectable radio frequency connector 758 to at least one passive antenna.

In some examples, a memory 761 may be operably coupled to switch control interface 763. Memory 761 may be a non-volatile memory component that may comprise information identifying the docked DRFU 750 and enable it to be correctly identified and configured by MBCU 700.

During a receive phase of the DRFU 750, the duplexer 756 may selectively couple a received signal present on at least one external connectable radio frequency connector 758 to an input of a low noise amplifier 762 and an optional filter 764, for example, a band pass filter. An output of filter 764 or low noise amplifier 762 may be operably coupled to radio frequency down-conversion module 712 within the MCBU 700.

In this example, as DRFU 750 may be utilised to couple via for example at least one external connectable radio frequency connector 758 to a passive antenna, there may be fewer power amplifiers 752 required as the antenna in question may constitute a plurality of antenna elements ganged together. These individual power amplifier 752 receiver paths may be configured to support a multitude of network element operations such as supporting MIMO (i.e. 2x2, 4x4 etc.), different bands of operation, carrier aggregation over a plurality of bands, and multiple air interface standards. The plurality of connectors 780 may typically be operably coupled to coaxial feed cables, allowing coupling of passive antenna systems.

Referring to FIG. 8, a simplified block diagram of the modular antenna integrated radio system 470 of FIG. 4 is illustrated, comprising MBCU 800 and DRFU 850. In this example, the operation of MBCU 800 may be substantially the same as that discussed for MBCU 500 of FIG. 5 or FIG. 7. As a result, explanation of FIG. 8 will mainly focus on features that have not been previously discussed.

In this example, DRFU 850 may be an antenna integrated module 850, and may be operably docked to MBCU 800 via docking station/interface 860. Further, DRFU 850 may have a plurality of connections, in this example one transmitter and one receiver, per column of passive antenna elements of common polarisation 880.

In this example, radio frequency up-conversion module 810 may transmit a signal via docking station/module 860 to an input of docked DRFU 850. At least one power amplifier module 852 may receive the transmitted signal before outputting the transmitted signal into a duplexer 856 via a transmit t feed 854. A coupling arrangement 855 may couple a portion of this transmitted signal to radio frequency switch matrix 861 . The coupled portion of the transmitted signal may be passed onto a calibration transceiver within the MBCU 800. In this example, the coupling arrangement 855 may only be situated on transmit antenna element feeds for example for the purpose of DPD feedback.

During a transmit phase of the DRFU 850, the duplexer 856 may selectively output the transmitted signal onto a connection 859 to, for example, a corporate feed network 881 of a column of passive antenna elements of common polarisation 880. The corporate feed network 881 may comprise, at least, a passive phase shifter, which may be an electromechanical phase shifter, 882 to allow a degree of beam tilt on the antenna. The corporate feed network 881 may be designed such that the phase and/or amplitude resulting from splitting of each signal is determined by the length of cable 884 to each element and also by the setting of passive phase shifter 882 in series with cable 884.

In some examples, a memory module 862 may be operably coupled to switch control interface 863. Memory 862 may be a non-volatile memory component that may comprise information identifying the docked DRFU 850 and enable it to be correctly identified by MBCU 800.

During a receive phase of the DRFU 850, the duplexer 856 may selectively couple a received signal onto a radio frequency feed 858, which may be operably coupled to an input of a low noise amplifier 864 and an optional filter 866, for example, a band pass filter. An output of filter 866 or low noise amplifier 864 may be operably coupled to radio frequency down-conversion module 812.

As discussed above, examples of the invention may provide a modular antenna system that may be operable to solve one or more of the previously discussed potential technical problems within the prior art. For example, as discussed above, a modular antenna system may allow partitioning of critical and less critical components. Situating critical components within an MBCU may have an advantage of allowing quicker, less expensive and easier replacement of critical components that may have failed within the MBCU, as the entire antenna system may not have to be removed from its mast top position.

Further, a modular antenna system may allow constituent parts of the antenna system to be installed separately. This may have an advantage of reducing the total weight of each constituent part, so that a less expensive manual installation may be performed. Furthermore, separating components into a modular system may have an advantage of allowing components with a similar operating temperature to be grouped together. In this manner, thermal management of a modular antenna system may be advantageously improved. Finally, a modular antenna system may allow for improved upgradability, for example by having a range of DRFUs that can be replaced and/or upgraded. This may have an advantage of providing a system that can be easily and inexpensively adapted and upgraded so that it may support latest and future functionality and frequency bands, for example.

Front end adaptations from market to market generates the most product variants, where in the aforementioned examples all variant processing from a hardware stance may be substantially contained in a standalone dockable module. This allows for original equipment manufacturers (OEMs) to develop more product variants without a need to develop and qualify the entirety of a DRFU and MBCU, thereby alleviating much of the development cost and time.

Furthermore, the costs associated with network operators in terms of site lease cost may be alleviated, as aesthetically all units appear as though it is one integrated unit therefore decreasing lease and taxes associated with separate units.

Additionally, allowing units to be serviceable without the need to uninstall the entirety of for example an AAS installation allows for quicker and less costly service costs when performing network maintenance.

Moreover, allowing operators to upgrade equipment without the need to dismantle or obsolete the installed network elements when doing network upgrades allows for savings and a degree of future proofing the equipment hardware installed.

Allowing for units to be installed as modules further helps alleviate the constraints on equipment manufacturers, as any one installed equipment needs to be less than 26kg to comply with health and safety regulations. For equipment where DRFUs and MBCUs are integrated as one installation the engineering challenge to keep below 26kg can be expensive in terms of engineering optimisation.

Additionally, in accordance with example embodiments, electronics may be partitioned such that devices capable of working at higher ambient temperatures may be co-located. Power amplifier devices, for example being co-located in the DRFU, allows for the thermal management of such devices to fluctuate beyond that desirable in standard industrial grade electronics as that contained in the DRFU. PA devices can generally operate at higher ambient temperatures and since operating continuously at temperature is a significant contributor to device reliability thus portioning and collocating some of the high power RF electronics on the DRFU allows for optimisation of system reliability.

Furthermore, fluctuations in temperature closely follow the PA output power(s). Thus, the electronics in the MBCU will largely stay constant irrespective of the transmitter power. Tracking fast changing thermal variations is a difficult design task and may be mitigated by virtue of co-locating the PA(s) in a separate module, the DRFU.

Referring now to FIG. 9, there is illustrated a typical computing system 900 that may be employed to implement signal processing functionality in embodiments of the invention. Computing systems of this type may be used in network elements/ wireless communication units. In some examples, the computer program and storage media may be located in the cloud or somewhere in the network of the operator environment, for example at an Operations and Management Centre (OMC). Those skilled in the relevant art will also recognize how to implement the invention using other computer systems or architectures. Computing system 900 may represent, for example, a desktop, laptop or notebook computer, hand-held computing device (PDA, cell phone, palmtop, etc.), mainframe, server, client, or any other type of special or general purpose computing device as may be desirable or appropriate for a given application or environment. Computing system 900 can include one or more processors, such as a processor 904. Processor 904 can be implemented using a general or special-purpose processing engine such as, for example, a microprocessor, microcontroller or other control logic. In this example, processor 904 is connected to a bus 902 or other communications medium.

Computing system 900 can also include a main memory 908, such as random access memory (RAM) or other dynamic memory, for storing information and instructions to be executed by processor 904. Main memory 908 also may be used for storing temporary variables or other intermediate information during execution of instructions to be executed by processor 904. Computing system 900 may likewise include a read only memory (ROM) or other static storage device coupled to bus 902 for storing static information and instructions for processor 904.

The computing system 900 may also include information storage system 91 0, which may include, for example, a media drive 912 and a removable storage interface 920. The media drive 912 may include a drive or other mechanism to support fixed or removable storage media, such as a hard disk drive, a floppy disk drive, a magnetic tape drive, an optical disk drive, a compact disc (CD) or digital video drive (DVD) read or write drive (R or RW), or other removable or fixed media drive. Storage media 918 may include, for example, a hard disk, floppy disk, magnetic tape, optical disk, CD or DVD, or other fixed or removable medium that is read by and written to by media drive 912. As these examples illustrate, the storage media 918 may include a computer-readable storage medium having particular computer software or data stored therein.

In alternative embodiments, information storage system 910 may include other similar components for allowing computer programs or other instructions or data to be loaded into computing system 900. Such components may include, for example, a removable storage unit 922 and an interface 920, such as a program cartridge and cartridge interface, a removable memory (for example, a flash memory or other removable memory module) and memory slot, and other removable storage units 922 and interfaces 920 that allow software and data to be transferred from the removable storage unit 918 to computing system 900.

Computing system 900 can also include a communications interface 924. Communications interface 924 can be used to allow software and data to be transferred between computing system 900 and external devices. Examples of communications interface 924 can include a modem, a network interface (such as an Ethernet or other NIC card), a communications port (such as for example, a universal serial bus (USB) port), a PCMCIA slot and card, etc. Software and data transferred via communications interface 924 are in the form of signals that can be electronic, electromagnetic, and optical or other signals capable of being received by communications interface 924. These signals are provided to communications interface 924 via a channel 928. This channel 928 may carry signals and may be implemented using a wireless medium, wire or cable, fibre optics, or other communications medium. Some examples of a channel include a phone line, a cellular phone link, an RF link, a network interface, a local or wide area network, and other communications channels.

In this document, the terms 'computer program product' 'computer-readable medium' and the like may be used generally to refer to media such as, for example, memory 908, storage device 918, or storage unit 922. These and other forms of computer-readable media may store one or more instructions for use by processor 904, to cause the processor to perform specified operations. Such instructions, generally referred to as 'computer program code' (which may be grouped in the form of computer programs or other groupings), when executed, enable the computing system 900 to perform functions of embodiments of the present invention. Note that the code may directly cause the processor to perform specified operations, be compiled to do so, and/or be combined with other software, hardware, and/or firmware elements (e.g., libraries for performing standard functions) to do so.

In an embodiment where the elements are implemented using software, the software may be stored in a computer-readable medium and loaded into computing system 900 using, for example, removable storage drive 922, drive 912 or communications interface 924. The control logic (in this example, software instructions or computer program code), when executed by the processor 904, causes the processor 904 to perform the functions of the invention as described herein.

It will be appreciated that, for clarity purposes, the above description has described embodiments of the invention with reference to different functional units and processors. However, it will be apparent that any suitable distribution of functionality between different functional units or processors, for example with respect to the MBCU or DRFU, may be used without detracting from the invention. For example, functionality illustrated to be performed by separate processors or controllers may be performed by the same processor or controller. Hence, references to specific functional units are only to be seen as references to suitable means for providing the described functionality, rather than indicative of a strict logical or physical structure or organization.

Aspects of the invention may be implemented in any suitable form including hardware, software, firmware or any combination of these. The invention may optionally be implemented, at least partly, as computer software running on one or more microprocessors for example, any form of data processors and/or digital signal processors. Thus, the elements and components of an embodiment of the invention may be physically, functionally and logically implemented in any suitable way. Indeed, the functionality may be implemented in a single unit, in a plurality of units or as part of other functional units.

Although the present invention has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the scope of the present invention is limited only by the accompanying claims. Additionally, although a feature may appear to be described in connection with particular embodiments, one skilled in the art would recognize that various features of the described embodiments may be combined in accordance with the invention. In the claims, the term 'comprising' does not exclude the presence of other elements or steps.

Furthermore, although individually listed, a plurality of means, elements or method steps may be implemented by, for example, a single unit or processor. Additionally, although individual features may be included in different claims, these may possibly be advantageously combined, and the inclusion in different claims does not imply that a combination of features is not feasible and/or advantageous. Also, the inclusion of a feature in one category of claims does not imply a limitation to this category, but rather indicates that the feature is equally applicable to other claim categories, as appropriate. Furthermore, the order of features in the claims does not imply any specific order in which the features must be performed and in particular the order of individual steps in a method claim does not imply that the steps must be performed in this order. Rather, the steps may be performed in any suitable order. In addition, singular references do not exclude a plurality. Thus, references to 'a', 'an', 'first', 'second', etc. do not preclude a plurality.

Claims

1 . A network element (MBCU) for a mast-top installation comprising:

a baseband converter module comprising :

at least one data interface; and

at least one microprocessor operably coupled to the at least one data interface and arranged to configure signals within the network element;

wherein the baseband converter module further comprises or is operably coupled to at least one radio frequency mast-top docking station, electrically coupled to the at least one data interface and for physically receiving a corresponding at least one removable radio frequency mast-top module comprising a memory that stores data to allow determination of at least one configuration of the at least one removable radio frequency mast-top module; and

wherein the at least one microprocessor is arranged to interrogate the memory of a docked at least one removable radio frequency mast-top module via the at least one radio frequency mast-top docking station to determine the at least one configuration thereof and interoperate therewith.

2. The network element of Claim 1 wherein the baseband converter module further comprises at least one frequency conversion module operably coupled to the at least one microprocessor and arranged to perform at least one of:

up-convert baseband data signals to radio frequency signals received from the at least one microprocessor for passing to a docked at least one removable radio frequency mast-top module via the at least one data interface; and

down-convert radio frequency signals to baseband data signals received from a docked at least one removable radio frequency mast-top module via the at least one data interface for passing to the at least one microprocessor.

3. The network element of Claim 1 or Claim 2 wherein the network element is substantially frequency band agnostic and a plurality of radio frequency mast-top docking stations receive a plurality of removable radio frequency mast-top modules to support a plurality of different frequency bands of operation.

4. The network element of any preceding Claim wherein the at least one microprocessor is programmable via the at least one radio frequency mast-top docking station memory interface port.

5. The network element of any preceding Claim wherein the at least one microprocessor is configured to program the at least one removable radio frequency mast-top module via the at least one radio frequency mast-top docking station memory interface port.

6. The network element of any preceding Claim wherein the at least one microprocessor is arranged to interrogate the memory and to identify the docked at least one removable radio frequency mast-top module.

7. The network element of Claim 6 wherein the at least one microprocessor is arranged to interrogate the memory and to determine one or more of the following parameters of the at least one removable radio frequency mast-top module: a serial number, a model number, an array dimension, an address table for selecting each antenna element of the array for transmit and receive operation, one or more frequency bands supported mapping of transmit or receive paths in use, an output power capability, one or more calibration parameters for a feedback circuit, a digital predistortion setting, antenna array configuration mapping, a date of manufacture, final production test data, a manufacturer code, a memory interface configuration format.

8. The network element of Claim 6 wherein the at least one microprocessor is arranged to interrogate the memory of the at least one removable radio frequency mast-top module and determine at least one configuration parameter by at least one from a group of: searching a database locatable on the signal processing module, or when operating in a remote location accessible though at least one backhaul interface using the interrogated memory information.

9. The network element of Claim 6 wherein the at least one microprocessor is arranged to interrogate the memory of the docked removable radio frequency mast-top module to determine a capability of a combined network element comprising at least the baseband converter module and the at least one removable docked radio frequency mast-top module.

10. The network element of any of preceding Claims 6 to 9 wherein the baseband converter module further comprises a backhaul interface operably coupled to the at least one microprocessor to establish a connection with a core network after the at least one microprocessor interrogates the memory of the at least one removable radio frequency mast-top module and in response thereto configure at least one of: the baseband converter module, the at least one removable radio frequency mast-top module via the at least one radio frequency mast-top docking station.

1 1 . The network element of Claim 10 wherein the at least one microprocessor is arranged to operate the at least one removable docked radio frequency mast-top module in at least one of: an output power thereof, at least one antenna beam setting, a carrier frequency, at least one beam-tilt angle, an air-interface protocol, band selection of one or more radio frequency circuits.

12. A method for operating a network element (MBCU) for a mast-top installation comprising a baseband converter module comprising at least one data interface; and at least one microprocessor operably coupled to the at least one data interface and arranged to configure signals within the network element; the method comprising at the network element: physically receiving a corresponding at least one removable radio frequency mast-top module comprising a memory;

electrically coupling the baseband converter module to at least one radio frequency mast-top docking station,

electrically coupling the baseband converter module to the at least one data interface;

interrogating the memory to determine at least one configuration of a docked at least one removable radio frequency mast-top module from via the at least one radio frequency mast-top docking station; and

interoperating with the docked at least one removable radio frequency mast-top module via the at least one radio frequency mast-top docking station.

13. A non-transitory computer program product comprising executable program code for operating a network element (MBCU) for a mast-top installation, the executable program code operable for, when executed at a communication unit, performing the method of Claim 12.

14. A radio frequency mast-top module (dockable DRFU) for a mast-top installation comprising : a plurality of band-specific radio frequency components;

an interface for removably physically locating the radio frequency mast-top module in, and electrically coupling to, at least one radio frequency mast-top docking station for routing radio frequency signals there through; and

a memory that stores configuration data of the at least one removable radio frequency mast- top module;

wherein the memory of the radio frequency mast-top module, when docked in the at least one radio frequency mast-top docking station, is arranged to be interrogated to allow determination of at least one configuration of the radio frequency mast-top module in order for the plurality of band-specific radio frequency components to interoperate with the at least one radio frequency mast-top docking station.

15. The radio frequency mast-top module of Claim 14 is at least part of a remote radio head and comprises at least one external connector for coupling at least one RF signal to at least one antenna.

16. The radio frequency mast-top module of Claim 14 is at least part of an active antenna system (AAS) or antenna integrated radio and comprises a plurality of antenna element coupled to the plurality of band-specific radio frequency components.

17. The radio frequency mast-top module of any of preceding Claims 14 to 1 6 wherein the plurality of band-specific radio frequency components comprises a plurality of duplex filters.

18. The radio frequency mast-top module of any of preceding Claims 14 to 1 7 wherein the interface is operably coupled to at least one RF switch to select and route for at least one coupled portion of at least one signal to or from an antenna element feed to support beamforming calibration.

19. The radio frequency mast-top module of any of preceding Claims 14 to 1 8 wherein the interface is operably coupled to route for at least one coupled portion of at least one signal from an antenna feed to support at least one of: power amplifier predistortion measurements, power amplifier predistortion feedback signals.

20. The radio frequency mast-top module of any of preceding Claims 14 to 19 further comprising a plurality of switches operably coupled to a plurality of antenna elements via a switched feedback circuit, wherein the interface is operably coupled to at least one switch arranged to provide a feedback signal via the switched feedback circuit.

21 . The radio frequency mast-top module of any of preceding Claims 14 to 20 wherein the interface comprises at least one port to support diagnostic operations run on interface signals passing there through.

22. The radio frequency mast-top module of any of preceding Claims 14 to 21 wherein the interface comprises at least one port to support software configurability of feedback networks.

23. The radio frequency mast-top module of any of preceding Claims 14 to 22 wherein the interface is operably coupled to the memory to and, when docked in the at least one radio frequency mast-top docking station, is arranged to be interrogated to identify at least one of: a configuration status, a build date, a serial number, one or more calibration parameters.

24. A method for operating a removable radio frequency mast-top module (dockable DRFU) for a mast-top installation comprising a memory and a plurality of band-specific radio frequency components; the method comprising at the removable radio frequency mast-top module:

storing configuration data of the removable radio frequency mast-top module;

physically and electrically coupling the removable radio frequency mast-top module to a baseband converter module via at least one radio frequency mast-top docking station ;

receiving a memory interrogation to determine at least one configuration of the removable radio frequency mast-top module from the baseband converter module via the at least one radio frequency mast-top docking station and forwarding at least one configuration data to the baseband converter module; and

interoperating with the baseband converter module via the at least one radio frequency mast- top docking station.

25. A non-transitory computer program product comprising executable program code for operating a removable radio frequency mast-top module, the executable program code operable for, when executed at a communication unit, performing the method of Claim 24.