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WO2017100826A1 - Améliorations concernant un fonctionnement de station d'émetteur-récepteur de base (bts) dans des systèmes de télécommunication cellulaire - Google Patents

Améliorations concernant un fonctionnement de station d'émetteur-récepteur de base (bts) dans des systèmes de télécommunication cellulaire Download PDF

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Publication number
WO2017100826A1
WO2017100826A1 PCT/AU2016/051085 AU2016051085W WO2017100826A1 WO 2017100826 A1 WO2017100826 A1 WO 2017100826A1 AU 2016051085 W AU2016051085 W AU 2016051085W WO 2017100826 A1 WO2017100826 A1 WO 2017100826A1
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WO
WIPO (PCT)
Prior art keywords
base station
radio
sector
configuration
antenna
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/AU2016/051085
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English (en)
Inventor
Frank John STRACHAN
Brendan Horsfield
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Kaelus Pty Ltd
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Kaelus Pty Ltd
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Filing date
Publication date
Priority claimed from AU2015905248A external-priority patent/AU2015905248A0/en
Application filed by Kaelus Pty Ltd filed Critical Kaelus Pty Ltd
Publication of WO2017100826A1 publication Critical patent/WO2017100826A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0491—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas using two or more sectors, i.e. sector diversity
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. Transmission Power Control [TPC] or power classes
    • H04W52/02—Power saving arrangements
    • H04W52/0203—Power saving arrangements in the radio access network or backbone network of wireless communication networks
    • H04W52/0206—Power saving arrangements in the radio access network or backbone network of wireless communication networks in access points, e.g. base stations
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Definitions

  • the present invention relates generally to cellular telecommunication systems, and more specifically to altering/modifying the operation of base transceiver stations (BTSs) used in cellular telecommunication systems.
  • BTSs base transceiver stations
  • a significant one of these impediments is that (prior to the present invention) it has been difficult or impossible for cellular telecommunication network operators to be able to turn individual radios of a given cellular network BTS on/off. And the reason for this is mainly because doing so has previously required access or permissions to manipulate or operate the underlying BTS operating systems and software.
  • these underlying BTS operating systems and software are generally provided and managed by the suppliers/manufacturers of the BTS radio equipment (e.g. the manufacturers of the actual transmitter/receiver hardware, etc), and moreover these suppliers/manufacturers of BTS radio equipment/hardware typically impose extremely tight security controls on the equipment operating systems and software, and on access thereto.
  • One option that is sometimes used for achieving savings in terms of wireless BTS power consumption is to deploy/mount BTS radios at the top of the BTS tower/mast, near the BTS antennas, rather than e.g. at the base of the tower/mast which is further away from the antennas. The purpose of this is to achieve power savings by reducing the length of feeder cables extending between the BTS radios and the BTS antennas, thereby minimising feeder cable losses. Turning down the Tx (transmit) power on radios at low traffic times is also sometimes used to save energy.
  • the invention relates generally to apparatus for use in a multi sector base station, wherein the base station includes a plurality of sector antennas and a base station radio for each sector antenna, and wherein the apparatus is operable:
  • o downlink signals from a base station radio are conveyed to that radio's corresponding sector antenna
  • o at least one of the base station radios is powered off, and o for each sector antenna whose base station radio is powered off, downlink signals to said sector antenna are sent from a base station radio which is powered on.
  • o uplink signals received by a sector antenna may be conveyed to that antenna's corresponding base station radio
  • o uplink signals received by a sector antenna whose base station radio is powered off may be conveyed to a base station radio which is powered on.
  • o all but one of the base station radios may be powered off, o downlink signals to any sector antenna whose base station radio is powered off may be sent from the one base station radio which is powered on, and
  • o uplink signals received by a sector antenna whose base station radio is powered off may be conveyed to the one base station radio which is powered on.
  • a different frequency may be used for uplink signals received, and downlink signals sent, by each sector antenna, and
  • o the same frequency may be used for uplink signals received, and downlink signals sent, by all sector antennas.
  • each sector antenna may includes at least two antennas, namely a Main antenna and a Diversity antenna, and
  • each base station radio may send downlink signals to its corresponding Main and Diversity antennas
  • o uplink signals received by the Main and Diversity antennas associated with each base station radio may be conveyed to that base station radio
  • the one base station radio which is powered on may send downlink signals to all of the Main and Diversity antennas, and
  • o uplink signals received by all Main and Diversity antennas may be conveyed to the one base station radio which is powered on.
  • separate apparatus may be provided for: ⁇ converting the base station's mode of operation between the first configuration and the second configuration for the Main antennas, and
  • the apparatus may include a controller which is operable to interpret measurements of the base station's traffic level and to determine whether to convert the base station's mode of operation from the first configuration to the second configuration, or from the second configuration to the first configuration.
  • the controller may also be operable:
  • the apparatus may also incorporate one or more switches, and it may be that by switching the switch(es) appropriately the apparatus is operable convert the base station's mode of operation between the first configuration and the second configuration.
  • the apparatus may be functionally connected in between the sector antennas and their corresponding base station radios.
  • Each sector antenna may have an antenna feeder cable which connects the antenna to the apparatus, and each radio may have a radio feeder cable which connects the radio to the apparatus.
  • the apparatus may also include a first filter module for each of the respective antenna feeder cables, and the respective antenna feeder cables may connect the respective sector antennas to the respective first filter modules.
  • the apparatus may include a second filter module for each of the respective radio feeder cables, and the respective radio feeder cables may connect the respective base station radios to the respective second filter modules.
  • Each of the first filter modules, and each of the second filter modules may include a Tx filter and an Rx filter.
  • the apparatus may incorporate one or more switches.
  • the one or more switches may be connected functionally in between the first filter modules and the second filter modules, and the first filter modules and second filter modules may be operable to block passive intermodulation distortion (PIM) (in uplink and/or downlink signals) that may be created by the one or more switches or other components of the apparatus that are connected functionally between the first filter modules and the second filter modules.
  • PIM passive intermodulation distortion
  • the apparatus may further include an uplink splitter/combiner and a downlink splitter.
  • the uplink splitter/combiner and the downlink splitter may be connected functionally in between the first filter modules and the second filter modules, and
  • the downlink splitter may be operable to split a downlink signal produced by the one radio that is powered on, so that said signal is conveyed to all of the sector antennas, and
  • the uplink splitter/combiner may be operable to (collect or) combine uplink signals received by the respective sector antennas such that a resultant/combined signal is conveyed from the uplink splitter/combiner to the one radio that is powered on.
  • the apparatus may be frequency band specific, and so for multiband base stations, a number of different or differently tuned apparatuses may be provided for use in the different frequency bands used by the base station.
  • traffic levels at the base station may be continuously monitored. Traffic level monitoring may be performed by monitoring the downlink traffic on each sector.
  • the invention relates generally to a method for controlling the operating configuration of a multi sector base station, wherein the base station includes a plurality of sector antennas and a base station radio for each sector antenna, and wherein the method includes:
  • the base station o causing the base station to operate in a first configuration wherein all base station radios are powered on and downlink signals from a base station radio are conveyed to that radio's corresponding sector antenna, and if the base station's traffic level is below the threshold level:
  • the base station to operate in a second configuration wherein at least one of the base station radios is powered off, and for each sector antenna whose base station radio is powered off, downlink signals to said sector antenna are sent from a base station radio which is powered on.
  • all but one of the base station radios may be powered off, downlink signals to any sector antenna whose base station radio is powered off may be sent from the one base station radio which is powered on, and
  • uplink signals received by a sector antenna whose base station radio is powered off may be conveyed to the one base station radio which is powered on.
  • the method may further comprise:
  • the method may also involve continuously monitoring traffic levels at the base station, and/or performing traffic level monitoring by monitoring the downlink traffic on each sector.
  • the invention relates generally to apparatus for use in a multi sector base station, wherein the base station includes a plurality of sector antennas and a base station radio for each sector antenna, and wherein the apparatus is operable to cause the base station to operate in:
  • downlink signals to all sector antennas may be sent from one of the base station radios.
  • the one base station radio that sends downlink signals to all sector antennas may be selectable from among all or some of the base station radios.
  • uplink signals received by each sector antenna may be conveyed to that antenna's corresponding base station radio.
  • the invention relates generally to a base station incorporating an apparatus as described above and/or as described in more detail below with reference to the Figures.
  • the invention relates generally to a base station when operated according to or using the method as described above.
  • the invention relates generally to installation (on or in a base station) of an apparatus of the kind described above and/or described in more detail below with reference to the Figures.
  • Figure 1 Graphical representation of the power consumption of different categories of radio access equipment used in cellular networks
  • Figure 2 Illustration of the way using hexagons, rather than e.g. circles, to schematically represent the geographical area of coverage provided by cellular radio antennas allows representation of the collective/overall coverage area with no gaps
  • FIG 3 Graphical representation of (i) an omnidirectional cell site (an "omni-site"), (ii) a one sector cell site (a “one-sector-site”), (iii) a two sector cell site (a "two-sector-site”) and (iv) a three sector cell site (a "three-sector-site”)
  • FIG. 4 Graphical representation of BTS locations, cell/sector boundaries and cell "radius” distances as used in most modern "three sectors per cell site” configurations
  • FIG. 7 Illustration of a "4, 12" frequency re-use pattern in the "normal mode” (I), which becomes a "4, 4" frequency re-use pattern in the "switched mode” (II)
  • FIG 8 Illustration of a “7, 21 " frequency re-use pattern in the "normal mode” (I), which becomes a “7, 7” frequency re-use pattern in the "switched mode” (II)
  • FIG. 9 Photograph of a typical three sector base transceiver station (BTS) with the antenna mounted at the top of the mast etc
  • FIG 10 Schematic representation of the radio and antenna equipment of a typical three sector base transceiver station (BTS)
  • FIG. 1 Schematic representation of the radio and antenna equipment of a typical three sector base transceiver station (BTS) fitted with Sector Switching Devices (SSD)
  • FIG. 12 Schematic representation of functional electronics used in the SSD in the "normal" mode
  • FIG. 13 Schematic representation of functional electronics used SSD in the "switched" mode.
  • Figure 14 Antenna radiation patterns of a multi-sector site switched using the SSD
  • Figure 15 Schematic representation of functional electronics used in an alternative (second) SSD configuration
  • FIG. 16 Schematic representation of functional electronics used in an alternative (third) SSD configuration
  • FIG. 17 Schematic representation of functional electronics used in an alternative (fourth) SSD configuration
  • FIG. 18 Schematic representation of functional electronics used in an alternative (fifth) SSD configuration
  • FIG 19 Block diagram of an alternative (sixth) and simple embodiment of the SSD, in which antennas from all three sectors are connected to BTS 1 (i.e. BTS Radio 1 ) when the SSD is in "Switched" mode, and BTS 2 and BTS 3 (i.e. BTS Radio 2 and BTS Radio 3) are placed into a shutdown state.
  • BTS 1 i.e. BTS Radio 1
  • BTS 2 and BTS 3 i.e. BTS Radio 2 and BTS Radio 3
  • FIG 20 Block diagram of another (seventh) alternative embodiment of the SSD, in which antennas from all three sectors can be connected to any one of BTS 1 (BTS Radio 1 ), BTS 2 (BTS Radio 2) and BTS 3 (BTS Radio 3) when SSD is in "Switched” mode, and the other 2 BTS Radios are placed into a shutdown state.
  • BTS 1 BTS Radio 1
  • BTS 2 BTS Radio 2
  • BTS 3 BTS Radio 3
  • Cellular telecommunication (sometimes called mobile telecommunication or mobile telephony) is a type of radio telecommunication in which a wireless connection is established or exists between a mobile phone handset of a "subscriber" (or “user") and one or more tower based transmitters.
  • the mobile phone handset is sometimes referred to as a "user equipment” (or “UE")
  • UE user equipment
  • BTS base transceiver station
  • BS base station
  • base transceiver station BTS, base station, BS, NodeB, NB and eNB
  • BTS base transceiver station
  • base station BS
  • NodeB base station
  • NB NodeB
  • eNB eNodeB
  • a base transceiver station usually has three antennas (or three antenna arrays), each of which provides 120 degrees of coverage around the base transceiver station tower.
  • the span or area of coverage provided by a BTS can be referred to as a "cell”.
  • the term "cell” is sometimes also used in slightly different but related ways - i.e. it is sometimes given a related but somewhat different meaning/definition - and this can be a source of confusion. This issue is discussed further below.
  • the mobile handset's communication connection is effectively passed from one local cell transmitter to another.
  • the connection may be passed from the BTS whose coverage area the user was initially/previously in to the BTS whose coverage area the user has moved into, or the connection might be passed from the coverage area provided by one transmitter to the coverage area provided by another transmitter even if both transmitters are actually physically mounted on the same BTS tower.
  • This process of transferring the communication connection from one local transmitter to another, so as to provide the user as they move with uninterrupted service (i.e. uninterrupted voice or data communication capability) is often referred to as "handover".
  • the methods and signalling protocols involved in facilitating handover can be quite complex but these need not be discussed any further for present purposes.
  • the shape of the geographical area of coverage provided by a cellular radio antenna is, in reality, often complicated and/or varying, for example, due to geographical or landscape features that may cause the shape of the coverage area to differ from one location to another, even if the same antenna and transmitter/receiver equipment (and the same amount of power, etc) is used, or possibly due to environmental or other time-varying factors that may cause radio-transmission conditions (and hence the shape of the radio coverage area) to change as conditions change with time.
  • hexagons to represent the shape of transmitter coverage areas helps to visualise a cellular network in terms of geographic layout, etc.
  • the hexagons used to represent the geographical areas of coverage provided by respective cellular radio antennas are really only an approximation of the actual shapes of the respective coverage areas.
  • hexagons and in particular regular hexagons
  • circles to represent the shape of coverage areas is because, as illustrated in Figure 2, regular hexagons tessellate (i.e. they fit together in a repeating pattern without gaps) and therefore they can represent immediately adjacent coverage areas in two dimensions without any gaps in between.
  • using hexagons allows the total area of radio coverage (i.e.
  • the black dot represents a "cell site".
  • a cell site is the location where a base transceiver station's (BTS's) radio equipment, including its antennas, etc, is situated.
  • BTS's base transceiver station's
  • a "cell site” may be said to provide radio coverage to a "cell”.
  • a cell site is always a location (or, in theoretical terms, it may be considered to be a point).
  • a cell which is serviced by a cell site is always a geographical area.
  • sectors are individual sub-areas of the total coverage are provided by a cell site.
  • the division of the total area of coverage provided by a cell site into multiple distinct sub-areas or “sectors” is typically done to make the cell sites (and the cellular network as a whole) more efficient and to enable the cell sites (and the network) to accommodate greater volumes of "traffic” (i.e. a larger number of calls and/or a greater amount of data transfer in a given amount of time).
  • cell sites (and BTSs) nowadays often/usually have three antennas (thus three sectors per cell site), and where this is the case each antenna typically provides 120 degrees of coverage around the tower.
  • cell the area of coverage provided by a cell site or BTS may be referred to as a "cell”.
  • cell the term “cell” is sometimes given a related but differing definition/meaning, and that this can lead to confusion. This will now be explained in further detail.
  • each cell site has three antennas each of which provides 120° of coverage such that together the cell site's (BTS's) antennas together provide 360° of coverage
  • each of the cell site's individual antennas often actually points and transmits into a different cell. Therefore, in these configurations, it is not the case that the cell site (BTS) is located in the centre of the cell, and it is not the case that the 360° of coverage provided by the cell site's three antennas together constitutes (or provides all the coverage for) a single cell. See the diagram marked "Wrong! in Figure 5.
  • each cell site (BTS) is located on the edge of a number of cells (in fact each cell site is located at the point of intersection between three different cells), and each of the cell site's antennas points and transmits into a different one of the respective cells. See the diagram marked "Right! in Figure 5.
  • omnidirectional omni cell
  • omni cell omni cell
  • omni cell omni cell
  • vector cell omni-cell
  • An omni cell is served by a BTS placed in its centre.
  • the BTS's antenna system transmits in all directions (360°), possibly equally or approximately equally in all directions, and the said BTS's antenna system can be constituted by (or in other words it may make use of) a single omnidirectional antenna (i.e. an "omni- antenna") or an array of sector antennas.
  • a "sector cell” is served by a BTS (a "sector site") located on the cell edge.
  • a sector site BTS uses a sector antenna (or a sector antenna array), e.g. a 120° or 180° antenna (or a 120° or 180° antenna array), to serve one sector cell (sector).
  • a sector site BTS may be provided with one, two or three such sector antennas (or sector antenna arrays), and each may be operable to service one sector cell (sector).
  • a particular sector site BTS may service one, two or three sector cells (sectors), as illustrated in the diagrams (ii), (iii) and (iv) respectively in Figure 3.
  • omni omnidirectional configurations
  • sector cell configurations are normally used to gain capacity (or in other words because they are able to handle a greater quantity of "traffic" - that is a higher volume of calls and/or data transmissions within a given period of time).
  • embodiments of the present invention is the ability to change (or switch) a cell site's antenna configuration between multi-sectored and omni.
  • embodiments may enable a three-sector cell site to switch to operating as an omni cell, and it may do so by making all the cell site's antennas (i.e. the antennas for all three respective sectors) operate from a single radio (thus with all three sectors operating at the same frequency).
  • all the cell site's antennas i.e. the antennas for all three respective sectors
  • it may also enable switching back so that the antennas for the (say) three respective sectors again operate using their own respective radios (and thus with the three sectors all operating at different frequencies, as normal). This will be discussed in further detail below.
  • each sector generally requires two (or more) Rx antennas and two (or more) Tx antennas.
  • Rx stands for or means “receiver” or “receiving” or “receive”
  • Tx stands for or means “transmitter” or “transmitting” or “transmit”.
  • antenna diversity refers to a scheme that uses two or more antennas to improve the quality and reliability of a wireless link.
  • Rx diversity i.e. Rx diversity for Rx antennas and Tx diversity for Tx antennas
  • Tx diversity refers to a scheme that uses two or more antennas to improve the quality and reliability of a wireless link.
  • Rx diversity i.e. Rx diversity for Rx antennas and Tx diversity for Tx antennas
  • Rx diversity refers to a scheme that uses two or more antennas to improve the quality and reliability of a wireless link.
  • a cell site gives/provides radio coverage to a cell.
  • the cell site is a location or a point, whereas the cell is a geographical area.
  • this interpretation actually holds true (i.e. it is correct) for omni-directional antenna systems - i.e. for omni cells.
  • "cell sites” and “cells” have required clearer definition, in particular as more sectors (or cells) have become associated with a cell site.
  • each cell site uses three different signalling frequencies - one for each of the cells it services.
  • the different frequencies allocated to the particular cells serviced by each respective cell site, and the way in which the different frequencies are arranged i.e. the direction in which the different frequencies are "pointed", or in other words the particular cell to which a particular frequency is allocated, to avoid cross-cell interference), and the way in which this arrangement (or this frequency orientation) differs or is repeated between or across cell sites, defines a pattern that can be repeated to enable frequency re-use as the number of cell sites increases.
  • Such a repeated arrangement of frequencies and cell sites is typically referred to as the "frequency re-use pattern" or "cell re-use pattern”.
  • the particular configuration in Figure 5 represents one possible frequency re-use pattern.
  • FIG. 6 Figure 7 and Figure 8.
  • Each of these Figures actually includes two diagrams (labelled (I) and (II) in each case), and in all of these diagrams each small circular (red) dot represents a base transceiver station (BTS) - i.e. a cell site.
  • BTS base transceiver station
  • the first diagram labelled (I) in each case relates to a "normal" BTS operating configuration (i.e. where the BTSs are not “switched” using the present invention/SSD).
  • the second diagram labelled (II) in each case relates to a "switched" BTS operating configuration (i.e. where the BTSs are "switched” using the present invention/SSD).
  • the numbers “1 ", "2” and “3" appearing in the adjacent cells serviced by this BTS indicate that the frequencies used in these cells are “frequency 1 ", “frequency 2” and “frequency 3", respectively, where each of these is of course a different frequency so that signal transmissions in one of these cells does not interfere with signal transmissions in either of the other two cells.
  • the different frequencies are often actually chosen specifically to help prevent or at least minimise inter-cell interference.
  • a range of interference mitigation techniques and methodologies are actually often used for preventing or minimising inter-cell interference, and also for preventing or minimising intra-cell interference.
  • Intra-cell-interference may be said to be interference between two or more users or UEs who are located within the same cell and who are transmitting simultaneously (and because they are located within the same cell they will necessarily be transmitting simultaneously on the same general frequency).
  • FIG. 6 the first diagram labelled (I) in Figure 6 relates to a "normal" BTS operating configuration. More specifically, this particular diagram illustrates a frequency re-use pattern that is commonly referred to as a "3, 9" pattern.
  • FIG 8 the first diagram labelled (I) in Figure 8 relates to a "normal" BTS operating configuration. More specifically, this particular diagram illustrates a frequency re-use pattern that is commonly referred to as a "7, 21 " pattern.
  • a typical three sector base transceiver station (BTS)
  • FIG 9 is a photograph of a typical three sector base transceiver station (BTS) 10. As shown in Figure 9, the BTS has a tower (or mast). The fact that the BTS mast in Figure 9 is painted with different coloured stripes may be for decorative or visibility purposes; however this has nothing to do with the present invention. Often the whole mast will be e.g. plain grey (or the colour of the concrete or steel from which the mast is made).
  • the BTS's antennas are mounted at the top of the mast.
  • the antennas for Sector 1 , Sector 2 and Sector 3 are labelled as such.
  • the antenna for each of Sectors 1 , 2 and 3 is labelled as an "antenna”, and whilst each appears to be a single generally vertical elongate unit, in fact, each of these is actually an antenna housing.
  • Each housing may contain only one antenna for the sector concerned, or (more typically) it may contain more than one antenna for the sector concerned. In the latter case, the housing would therefore contain an antenna "array" for that sector.
  • the antenna housings which are labelled as “Sector 1 antenna”, “Sector 2 antenna” and “Sector 3 antenna” each actually contain two antennas within the one housing.
  • the two antennas in each case (i.e. the two antennas within each of these housings), may be assumed to have opposite polarization to each other. This may allow any polarization signal to be received by a sector antenna.
  • the two oppositely polarised antennas will be referred to (as they normally are) as the "Main” antenna (or “Main” port) and the "Diversity” antenna (or “Diversity” port).
  • the three antennas each provide 120° of coverage
  • the antennas (or antenna arrays) for the respective sectors are mounted at the top of the mast.
  • the radios for the respective antennas are located at the base of the tower (in the case of Figure 9 they would actually be located in the small air conditioned building adjacent the base of the tower).
  • the radios could alternatively be mounted (and in some cases they are nowadays) at the top of the mast/tower with or near the antennas.
  • the radios could be mounted at some other place/height on the tower, or they could be located slightly away from the tower.
  • the mounting location of the radios is largely irrelevant to the operation of the present invention. That is to say, embodiments of the present invention may operate and may be used with different BTS configurations, e.g. regardless of whether the radios associated with the respective sector antenna arrays are located at the base of the mast, or the top, etc.
  • FIG. 10 is a schematic representation of the radio and antenna equipment associated with a typical three sector cellular (BTS) like the one depicted in Figure 9.
  • the radio connected to the Sector 1 antenna (array) is labelled as the Sector 1 BTS radio
  • the radio connected to the Sector 2 antenna (array) is labelled as the Sector 2 BTS radio
  • the radio connected to the Sector 3 antenna (array) is labelled as the Sector 3 BTS radio.
  • Each of the BTS sector radios is connected to its corresponding sector antenna (array) by two coaxial feeder cables 40, one of which (40M) connects the radio to the sector antenna's Main port/antenna and the other which (40D) connects the radio to the sector antenna's Diversity port/antenna.
  • BTSs base transceiver stations
  • all three radios are normally powered on (and remain on) no matter what the traffic levels (i.e. all three radios operate regardless of how much traffic or data is being transmitted via the BTS). It is this aspect of the normal operation of a base transceiver station which is a focus of the present invention.
  • SSD Sector Switching Device
  • the SSD operates to reduce energy consumption in a cellular telecommunication base transceiver station (BTS) by
  • shutting down parts of the base transceiver station equipment during low-traffic periods will reduce the amount of power consumed by the base transceiver station during those periods, and this should thereby help to achieve an overall reduction in the amount of power consumed by the base transceiver station.
  • the first aspect relates to monitoring the level of traffic at the BTS site.
  • the second aspect relates to actually shutting down, and turning on, the relevant portions of the base transceiver station equipment as required.
  • These two aspects are related because the first aspect (monitoring the level of traffic at the BTS site) is performed specifically in order to determine when to shut down parts of the base transceiver station equipment and when to turn them back on again.
  • monitoring the level of traffic at the BTS site can enable parts of the base transceiver station equipment to be shut down when the amount of traffic (and hence the demands on the base transceiver station equipment) drops below a certain threshold level.
  • it can enable the said parts of the base transceiver station equipment to be switched back on again when the amount of traffic (and the demands on the base transceiver station equipment) again equals or rises above the threshold level.
  • the traffic level at the BTS site from time to time is measured and/or quantified, and the way information or signals corresponding to measured or sampled traffic levels is generated and/or converted and then transmitted or provided to the SSD (i.e. for use in determining whether to switch off or turn on base transceiver station equipment) is also not critical. It is sufficient that the SSD can receive and use this information to determine when to turn the relevant base transceiver station equipment off and on.
  • the present invention is therefore more focused on the way in which parts of the base transceiver station equipment can be turned on and off, as required, based on monitored traffic level information.
  • the SSD could potentially be used (and it may potentially provide benefit) in any base transceiver station.
  • Most (if not all) base transceiver stations regardless of their location, experience some variation of fluctuation in traffic levels. Such variations of fluctuations may arise, for example, at different times of day. For instance (and in urban/populated areas particularly), daylight hours might see a considerable amount of telephone call/data traffic at a base transceiver station, and this traffic volume might actually increase in the early-mid evening (i.e. early-mid evening may be a "peak" traffic time). However, the darkness/night-time hours from late evening through until dawn may often see considerably lower volumes of telephone call and data traffic.
  • base transceiver stations which experience very large or dramatic variations in traffic volume levels, or which only experience high traffic volumes at particular times. Take, for example, a base transceiver station located near a large sporting stadium. At times when there is no sporting or other event taking place at the stadium (and when the stadium is consequently empty) the base transceiver station may experience little or no traffic at all. This may actually be the majority of the time.
  • base transceiver stations at other locations as well.
  • a base transceiver station located alongside a major highway may experience very high call/data transmission volumes at the times of day corresponding to peak road traffic/congestion (i.e. during the morning and/or evening "rush hour" when a constant and large number of people are driving past the base transceiver station making calls or transmitting data); however at other times such as during the middle of the day and more so during the night (when there is much less road traffic on the highway and hence far fewer people driving past the base transceiver station making calls/transmissions) the base transceiver station may experience far lower call/data transmission volumes.
  • Other base transceiver stations which might experience similar variations in traffic volumes include base transceiver stations located at or near universities, large educational institutions, conference centres, and the like, all of which may be heavily populated at some times of day but much less populated or empty at other times.
  • low demand periods may clearly help to reduce the drain on, and hence reduce the depletion rate of, the batteries, and this may be particularly beneficial when there is low traffic (and hence when there is no need to be powering the base transceiver station to the level, or depleting the batteries at the rate, needed for satisfying high or peak demand), and it may also be beneficial during periods of reduced or no sun exposure (when the solar cells will generally be generating less or no power).
  • Figure 10 contains a schematic representation of the radio and antenna equipment in a conventional three sector base transceiver station (BTS) 10.
  • Figure 1 1 is actually similar to Figure 10 in that it too shows the radio and antenna equipment in a three sector base transceiver station 10; however Figure 1 1 also shows the SSDs (note that there are two SSDs) interposed between the sector antennas and their corresponding sector radios.
  • the number and arrangement of the feeder cables 40M and 40D schematically represented is also different Figure 1 1 - this is in order accommodate the SSDs and their operation, as will become clearer from the discussion below.
  • the function of the SSDs is to facilitate "switching" between two base transceiver station operating configurations.
  • the "normal” configuration the coaxial feeder lines (40M and 40D) connect the respective sector antenna arrays to their corresponding sector radios (i.e. just as normal, as shown in Figure 10). So, for example, in the "normal” configuration, two feeder cables, 40M and 40D, will connect the Main and Diversity ports of the Sector 1 antenna array to the respective Main and Diversity ports of the Sector 1 radio, and another two feeder cables, 40M and 40D, will connect the Main and Diversity ports of the Sector 2 antenna array to the respective Main and Diversity ports of the sector 2 radio, etc.
  • the SSDs cause the feeder cables for all of the sector antenna arrays to connect to a single one of the BTS's sector radios.
  • the feeder cables 40M and 40D extending from the Main and Diversity ports on all three of the sector antenna arrays i.e. all six of these cables
  • the Main and Diversity SSDs can be located at the top of the base transceiver station tower (and they may be if this is where the radios are located), or alternatively they may be located at the base of the tower (if that is where the radios are), etc.
  • the SSDs also need not necessarily be located in the same place as the radios.
  • SSD switching is synchronised as between the Main port SSD and the Diversity port SSD such that both Main and Diversity switch at the same time. What is meant by "switching” is, of course, switching between the two BTS operating configurations mentioned above. This will be discussed further below. Detailed operation of the SSD in one embodiment
  • Figure 12 and Figure 13 contain a schematic representation of the functional electronics and components used inside an SSD 100 in accordance with one embodiment of the invention. Note that Figure 12 illustrates the SSD 100 in the "normal” mode, whereas Figure 13 illustrates the SSD 100 and the “switched” mode. The only difference between the two figures is therefore the position of the various switches.
  • Figure 12 and Figure 13 show the functional electronics for only one of the two SSDs required by a given BTS - i.e. they show functional electronics for only one of the SSDs in Figure 1 1 .
  • the SSD 100 in Figure 12 and Figure 13 could therefore by either the "Main” SSD 100M, or the "Diversity” SSD 100D, in Figure 1 1 .
  • FIG. 12 and Figure 13 also depicts the SSD controller 90.
  • the SSD controller 90 whilst depicted schematically as a separate, larger box, may actually be integrated in or as part of the base transceiver station (BTS) controller (shown inside the SSD controller box 90). Communications between SSD 100 and the SSD controller 90, and also DC power for the SSD 100, can be carried via the feeder cables 40.
  • BTS base transceiver station
  • the SSD controller (wherever it happens to be located and/or however it happens to be configured/implemented) is effectively the control centre for the SSD 100.
  • the controller 90 interprets measurements of BTS traffic levels and it determines when to initiate a "switching" instruction.
  • the controller 90 may be configured to "switch” the BTS from the "normal” mode to the “switched” mode when the traffic level (i.e. the amount of traffic/data passing through the BTS) drops below a certain threshold level. Conversely, the controller 90 may "switch” the BTS from the “switched” mode back to the "normal” mode when the traffic level equals or exceeds the threshold level.
  • traffic level i.e. the amount of traffic/data passing through the BTS
  • the controller 90 would send signals to the relevant base transceiver station radios to turn off before then signalling the SSD to switch from one configuration to the other.
  • the SSD controller 90 may communicate with the SSD 100 using any form or type of communication protocol.
  • any form or type of communication protocol for the avoidance of doubt, no limitation whatsoever exists on the communication method or protocol used, or on the way in which the SSD controller 90 and the SSD 100 exchange information.
  • one option that may be suitable for facilitating communication may be AISG.
  • AISG The Antenna Interface Standards Group, sometimes referred to using the acronym AISG, is actually a non-profit international consortium formed by collaboration between communication infrastructure manufacturers and network operators with the purpose of maintaining and developing a standard for digital remote control and monitoring of antenna line devices in the wireless industry.
  • the AISG is a standard-setting organisation (SSO).
  • SSO standard-setting organisation
  • AISG is often also used to refer, not to the organisation, but to the particular devices, protocols, etc, that have been developed and standardised by the organisation. Therefore, it is often actually the case that the term AISG refers to the standardised communication devices, protocols, etc, and that is how this term will be used herein.
  • AISG is based on a RS485 communication bus, which is a multi-device bus.
  • ALDs Antenna Line Devices
  • CNI Control Network Interface
  • TMAs Tower Mounted Amplifiers
  • ACU Antenna Control Unit
  • RRH Remote Electrical Tilt
  • RET Antenna Remote Electrical Tilt
  • the SSD controller 90 interprets measurements of traffic levels and determines when to initiate a "switching" instruction. In addition, the SSD controller 90 is also responsible for actually turning the relevant BTS radios off and on. The SSD controller 90 may communicate with the respective BTS radios using a data connection such as, for example, LAN or USB, although as above no limitation whatsoever exists on the communication method or protocol used, or on the way in which the SSD controller and the BTS radios exchange information.
  • a data connection such as, for example, LAN or USB, although as above no limitation whatsoever exists on the communication method or protocol used, or on the way in which the SSD controller and the BTS radios exchange information.
  • each of the antennas (which could all be Main antennas or Diversity antennas) has a feeder cable 40 which extends from the antenna into the SSD 100.
  • Each of the feeder cables 40 connects to a respective filter module 1 10. More specifically, the feeder cable which extends from Antenna 1 connects to a filter module 11 the feeder cable which extends from Antenna 2 connects to a filter module 1 10 2 and the feeder cable which extends from Antenna 3 connects to a filter module 1 10 3 .
  • Each of the respective filter modules 110 contains a Tx filter and an Rx filter.
  • the filter module 1 10-1 associated with Antenna 1 contains a Tx filter 1 10-i j x and an Rx filter 1 10 Rx
  • the filter module 1 10 2 associated with Antenna 2 contains a Tx filter 1 10 2 j x and an Rx filter 1 10 2 ,R x , etc.
  • Each of the respective BTS radios also has a feeder cable 40 which extends from the radio into the SSD 100.
  • Each of these feeder cables 40 connects to a respective filter module 170. More specifically, the feeder cable which extends from the BTS Radio 1 connects to a filter module 170 ⁇ the feeder cable which extends from the BTS Radio 2 connects to a filter module 170 2 and the feeder cable which extends from the BTS Radio 3 connects to a filter module 170 3 .
  • Each of the respective filter modules 170 again, contains a Tx filter and an Rx filter.
  • the filter module 170i associated with the BTS Radio 1 contains a Tx filter 170-i jx and an Rx filter 170-i ,Rx
  • the filter module 170 2 associated with the BTS Radio 2 contains a Tx filter 170 2jx and an Rx filter 170 2,Rx , etc.
  • the purpose of the respective filter modules 1 10 (associated with the respective antennas) and of the respective filter modules 170 (associated with the radios) is to block any passive intermodulation distortion (PIM), in both the Tx and Rx signals, that may be created by the other components in the SSD 100 such as the switches, three-way splitters, etc, discussed below.
  • PIM passive intermodulation distortion
  • the switches, splitters, etc are located between the filter modules 110 and the filter modules 170 such that any PIM they may produced does not pass through the filter modules and out of the SSD 100.
  • the SSD 100 also incorporates a number of switches 104 and 105. It is by “switching” these switches appropriately that the SSD 100 switches between the "normal” mode and the “switched” mode. This is discussed further below. Again, the actual switches (or switching components) used for the switches 104 and 105 is not critical, and the selection of appropriate components to achieve the function (described below) should be within the capability of a person skilled in this area.
  • the SSD 100 also incorporates a three-way Tx splitter 120 and a three-way Rx splitter (or combiner) 130.
  • the Tx splitter 120 operates in the "switched" mode to split the Tx signal from the single radio (BTS Radio 1 in the example of Figure 12 and Figure 13) so that that Tx signal is conveyed to and transmitted by all three of the antennas (Antenna 1 , Antenna 2 and Antenna 3).
  • the Rx splitter (combiner) 130 operates, again in the "switched” mode, to effectively “collect” or “combine” the Rx signals received by the three respective antennas (Antenna 1 , Antenna 2 and Antenna 3) so that they can be conveyed to the single radio (BTS Radio 1 in this example).
  • BTS Radio 1 in this example.
  • the "switched” mode will be discussed further below.
  • the actual splitter components used for the splitters 120 and 130 are not critical, and the selection of appropriate components to achieve the required function for these should be within the capability of a person skilled in this area.
  • the SSD 100 further incorporates a low noise amplifier (LNA) 160 on the uplink path from each of the antennas.
  • LNA low noise amplifier
  • uplink refers to signals transmitted by (i.e. sent from) a user equipment (e.g. from a mobile phone handsets or the like) to a BTS.
  • signals sent in the opposite direction namely from the BTS to an individual user equipment (or to multiple user equipments in a broadcast manner), are referred to as "downlink”.
  • the SSD separates the uplink and downlink signals using a duplexer filter. Furthermore, the SSD operates to switch them (i.e. the SSD switches the uplink and downlink signals) separately. More specifically, the downlink signals are switched by the switches 104, whereas the uplink signals are switched by the switches 105. See below.
  • the switches are controlled by a control board 109 within the SSD 100. The SSD control board 109 communicates with the SSD controller 90.
  • LNA 160 ! is located immediately after the Rx filter 1 10 Rx in the uplink direction.
  • LNA I6O 2 is located immediately after the Rx filter 1 0 2 ,Rx in the uplink direction, etc.
  • the purpose of the LNAs is to compensate for the insertion loss of the SSD in the uplink band.
  • the SSD controller 90 simply decides to continue operating the BTS in the "normal” mode (i.e. in the "normal'Yhigh-energy state).
  • the SSD controller 90 will decide to switch from the "switched” (low-energy) mode to the "normal” (higher-energy) mode. If/when this occurs, the SSD controller 90 sends a turn-on data signal to BTS Radio 2 and BTS Radio 3 to start up (recall that BTS Radio 1 is already on in the "switched'Vlow-energy mode). The SSD controller 90 then switches the sector 1 , 2 and 3 antennas to BTS Radio 1 , BTS Radio 2 and BTS Radio 3, respectively, thus placing the BTS in the "normal” (high-energy) operating state.
  • the SSD 100 incorporates a number of switches 104 and 105, and that the switches 104 switch the downlink signals whereas the switches 105 switch the uplink signals. Thus, it is by “switching” these switches 104 and 105 appropriately that the SSD 100 switches between the "normal” mode and the “switched” mode.
  • the way in which the switches 104 and 105 operate to “switch” the BTS from operating in the "normal” mode to operating in the "switched” mode, and vice versa can be understood by comparing Figure 12 with Figure 13. This is because Figure 12 depicts the SSD with all of the switches 104 and 105 shown in the position they adopt when in the "normal” (high-energy) mode. In contrast, Figure 13 depicts the SSD 100 with all of the switches 104 and 105 instead shown in the position they adopt when in the "switched” (low-energy) mode.
  • this first-reached switch 105 is (in the "normal” mode) in the position shown in Figure 12, the signal consequently flows therefrom directly to a second such switch 105, and because this second-reached switch 105 is (again in the "normal” mode) in the position shown in Figure 12, the signal consequently flows therefrom into the Rx filter 170 Rx of the filter module 170 ! . From there, the signal continues on directly (via the feeder cable 40) to the BTS Radio 1 .
  • the signal consequently flows therefrom directly to into the Rx filter 170 2 Rx or 170 3 Rx of the filter module 170 2 or 170 3 . From there, the signal continues on directly (via the feeder cable 40) to the BTS Radio 2 or 3.
  • this first-reached switch 104 is (in the "normal” mode) in the position shown in Figure 12, the signal consequently flows therefrom directly to a second such switch 104, and because this second -reached switch 104 is (again in the "normal” mode) in the position shown in Figure 12, the signal consequently flows therefrom through the detector and coupler 1 12 and into the Tx filter 1 10ij x of the filter module ⁇ ⁇ 0 ⁇ . From there, the signal continues on directly (via the feeder cable 40) to be transmitted by Antenna 1 to UE(s) serviced by Antenna 1 .
  • traffic levels at the BTS are continuously monitored. More specifically, traffic levels are continuously monitored on all three sectors.
  • the traffic level monitoring is actually achieved using couplers to sample the downlink signal of the BTS. More specifically, for each sector, a coupler is used to sample the transmitted signals and a detector is used to convert the RF signal into an equivalent DC voltage that is converted into a digital value for measurement.
  • the actual way in which traffic level monitoring is achieved i.e. the way in which the level of traffic at the BTS site is monitored and measured
  • the actual way in which traffic level monitoring is achieved is not critical to the invention.
  • the SSD controller 90 simply decides to continue operating the BTS in the "switched” mode (i.e. in the low-energy state).
  • the SSD controller 90 will decide to switch from the "normal” (high-energy) mode to the "switched” (low-energy) mode. If/when this occurs, the SSD controller 90 sends a turn-off/shutdown data signal to BTS Radio 2 and BTS Radio 3 (recall that BTS Radio 1 remains on in the "switched'Vlow-energy mode).
  • the SSD controller 90 then switches the sector 1 , 2 and 3 antennas all to BTS Radio 1 , thus placing the BTS in the "switched" (low-energy or energy saving) operating state in which one of three radios (BTS Radio 1 ) is left on, but the other two are turned off, thereby potentially leading to an energy consumption reduction of about two thirds or 66%.
  • this signal In the "switched" mode, when an uplink signal is received by Antenna 1 , this signal initially travels from Antenna 1 , along the feeder cable 40 to the filter module 1 10i . Being an uplink signal (and hence an Rx signal from the BTS's point of view), this signal then passes through the Rx filter 1 10 iRx and then through the LNA 160-1 (where it is amplified) before reaching a first switch 105. Because this first-reached switch 105 is (in the "switched” mode) in the position shown in Figure 13, the signal consequently flows therefrom into the three-way Rx combiner 130.
  • the signal is collected or combined with the uplink signals received by Antenna 2 and Antenna 3, and the resultant/combined signal is then conveyed from the three-way Rx combiner 130 to a second switch 105.
  • this second-reached switch 105 is (again in the "switched" mode) in the position shown in Figure 13, the resultant/combined signal flows into the Rx filter 170I ,R x of the filter module 170-i. From there, the resultant/combined signal continues on directly (via the feeder cable 40) to the BTS Radio 1 .
  • the said signal when an uplink signal is received by Antenna 2 or Antenna 3, the said signal initially travels from Antenna 2 or Antenna 3, along the relevant feeder cable 40 to the relevant corresponding filter module H O 2 or H O 3 . And, once again, being an uplink signal (and hence Rx from the BTS's point of view), the said signal then passes through the relevant Rx filter 1 10 2 , R x or 1 10 3! R x and then through the relevant LNA 160 2 or 160 3 (where it is amplified) before reaching a first switch 105.
  • this first-reached switch 105 is (in the "switched" mode) in the position shown in Figure 13, the signal (which it should be recalled was originally received by Antenna 2 or Antenna 3) consequently then flows from the first- reached switch 105 into the three-way Rx combiner 130 where it is collected or combined with the uplink signals received by the other of Antenna 3 or Antenna 2 and Antenna 1 .
  • the resultant/combined signal is then conveyed from the three-way Rx combiner 130 to the second switch 105, and as above, because this second-reached switch 1 05 is (in the "switched" mode) in the position shown in Figure 13, the resultant/combined signal flows into the Rx filter 170 iRx of the filter module ' ⁇ 70- ⁇ . From there, the resultant/combined signal continues on directly (via the feeder cable 40) to the BTS Radio 1 .
  • this first-reached switch 104 is (in the "switched” mode) in the position shown in Figure 13, the signal consequently flows from the first-reached switch 1 04 into the three-way Tx splitter 120.
  • the signal (which was originally generated by BTS Radio 1 ) is split (or duplicated) into three equal but separate/distinct signals (or signal copies), one each destined for Antenna 1 , Antenna 2 and Antenna 3.
  • Each of these separate signals is therefore conveyed from the three- way Tx splitter 120 to a respective one of the second -reached switches 104.
  • each of these second-reached switches 1 04 is (in the "switched" mode) in the position shown in Figure 13, the respective signals therefore continue through these respective second-reached switches 104, then through the relevant detector and coupler 1 12, 1 14 and 1 16, and into the relevant Tx filter 1 10-i Tx , 1 10 2 , ⁇ ⁇ and 1 1 0 3 T x of the corresponding filter modules 1 10i , 1 10 2 and H O 3 . And from there, the signals continue on directly (via the relevant feeder cables 40) to be transmitted by the relevant Antennas 1 , 2 and 3 to user equipments serviced by the BTS.
  • any downlink signal produced by the BTS is produced solely by BTS Radio 1 . Therefore, even though such a downlink signal (in the "switched” mode) becomes transmitted by all three of the antennas (Antenna 1 , 2 and 3), nevertheless the signal (which is transmitted by all three antennas) is necessarily at a single frequency. Accordingly, in the "switched” mode, any downlink signal produced by the BTS is transmitted by all three antennas on the same frequency.
  • diagram (II) in Figure 6 this diagram illustrates that if all BTSs are operating in a "switched" BTS operating configuration, there are again three distinct cell site frequency arrangements (again indicated by the colours green, yellow and blue, or at least by different shading), however each of these now (i.e. in the "switched” mode) uses only a single (i.e. the same) frequency.
  • the cell sites (BTS) that transmit using frequencies ⁇ 4,5,6 ⁇ for their respective cells when in the normal mode are shown instead using frequency ⁇ 4 ⁇ only for all three cells in the "switched" mode (however the choice of frequency ⁇ 4 ⁇ is again arbitrary, and it could be that frequency ⁇ 5 ⁇ only, or ⁇ 6 ⁇ only, is chosen, although this may also depend on the SSD design and configuration).
  • the cell sites (BTS) that transmit using frequencies ⁇ 7,8,9 ⁇ for their respective cells when in the normal mode are shown instead using frequency ⁇ 7 ⁇ only for all three cells in the "switched” mode.
  • diagram (II) in Figure 8 illustrates that if all BTSs are operating in a "switched" BTS operating configuration, there are again seven distinct cell site frequency arrangements (again indicated by the colours green, yellow, blue, purple, pink, cyan and orange, or at least by different shading), however each of these now (i.e. in the "switched” mode) uses only a single (i.e. the same) frequency.
  • the cell sites (BTS) that transmit using frequencies ⁇ 4,5,6 ⁇ for their respective cells when in the normal mode are shown instead using frequency ⁇ 4 ⁇ only for all three cells in the "switched" mode (however the choice of frequency ⁇ 4 ⁇ is again arbitrary, and it could be that frequency ⁇ 5 ⁇ only, or ⁇ 6 ⁇ only, is chosen, although this may also depend on the SSD design and configuration).
  • BTS cell sites
  • ⁇ 7,8,9 ⁇ , ⁇ 10, 1 1 , 12 ⁇ , ⁇ 13, 14,15 ⁇ , ⁇ 16, 17, 18 ⁇ and ⁇ 19,20,21 ⁇ in the normal mode - these are shown using frequency ⁇ 7 ⁇ only, ⁇ 10 ⁇ only, ⁇ 13 ⁇ only, ⁇ 16 ⁇ only and ⁇ 19 ⁇ only. Accordingly, if all BTSs are operating in a "switched" BTS operating configuration, a total of 7 x 1 - 7 distinct frequencies are used - hence this may be referred to as a "7, 7" pattern.
  • one of the important capabilities provided by embodiments of the present invention is the ability to switch a cell site's mode of operation between multi-sectored and omni. It is perhaps worth noting that the idea of configuring a multi -sectored BTS for omnidirectional operation - at least in the downlink direction - has been proposed previously. For instance, a patent application by Ericsson (US20140248906, "Methods and Arrangements for Positioning in Wireless Communications Systems”) describes a three sector BTS in which the downlink signals from the transmitter in BTS Radio 1 are broadcast from all three sector antennas simultaneously, thereby creating a quasi-omnidirectional radiation pattern.
  • Figure 14 illustrates antenna radiation patterns of a multi-sector site switched using the SSD.
  • the BTS's existing antennas are used in both normal mode and switched mode.
  • the radiation patterns for normal mode are coloured, and when SSD switches the antennas to single radio the pattern effectively is the black pattern. It can be seen that, in the "switched" mode (when the antennas are fed with the same frequency signal from a single BTS radio), the resulting antenna radiation pattern tends toward an omnidirectional pattern.
  • Figure 15 contains a schematic representation of the functional electronics and components used inside an SSD 200 in accordance with a second possible embodiment of the invention.
  • Figure 15 shows the functional electronics for only one of the two SSDs required by a given BTS - i.e. it show functional electronics for only one of the SSDs in Figure 1 1 .
  • the SSD 200 in Figure 15 could therefore be either the "Main” SSD 200M or the "Diversity" SSD 200D.
  • the embodiment of the SSD 200 differs from the embodiment of the SSD 100 in that the SSD 200 is only operable to switch the transmitter (not the receiver) to a single BTS radio.
  • the SSD 200 in Figure 15 even when the SSD switches the BTS to operate in the "switched" mode, uplink signals received by all three of the antennas (Antenna 1 , Antenna 2 and Antenna 3) are still conveyed directly to their respective BTS radios (BTS Radio 1 , BTS Radio 2 and BTS Radio 3), and not all to a single radio as is the case for SSD 100 in the "switched" mode.
  • any of the BTS radios (BTS Radio 1 , 2 or 3) can be selected/used as the transmission (Tx) source.
  • Figure 16 contains a schematic representation of the functional electronics and components used inside an SSD variant 300.
  • Figure 16 shows the functional electronics for only one of the two SSDs required by a given BTS - i.e. it show functional electronics for only one of the SSDs in Figure 1 1 .
  • the SSD 300 in Figure 16 could therefore be either the "Main” SSD 300M or the "Diversity” SSD 300D.
  • the SSD variant 300 depicted in Figure 16 will not be described in detail, because those skilled in this area should be able to readily interpret Figure 16, and understand the operation of the SSD 300, based on the explanations given above.
  • the SSD variant 300 differs from the embodiments of the SSD 100 and 200 in that the SSD 300 is not actually switchable at all. Instead, the SSD 300 could be installed as a retrofit to cause an existing multi (three) sector BTS to be (always) driven by a single BTS radio (Radio 1 in this example, although it could be any of the three radios). This could potentially prove useful if there is a need, for example, for greater range but low capacity in a particular location, and to therefore change the operation of the existing multi (three) sector BTS at that location to effectively operate in an "omni" fashion (which, as explained above, can be better for achieving greater range if with somewhat reduced capacity).
  • Radio 1 in this example, although it could be any of the three radios
  • Figure 17 contains a schematic representation of the functional electronics and components used inside an SSD 400 in accordance with a fourth possible embodiment of the invention.
  • Figure 17 shows the functional electronics for only one of the two SSDs required by a given BTS - i.e. it show functional electronics for only one of the SSDs in Figure 1 1 .
  • the SSD 400 could therefore be either the "Main” SSD 400M or the "Diversity” SSD 400D.
  • the embodiment of the SSD 400 differs from the embodiment of the SSD 100, and it is similar to the embodiment of the SSD 200, in that the SSD 400 is only operable to switch the transmitter (not the receiver) to a single BTS radio.
  • the SSD 400 in Figure 17 even when the SSD switches the BTS to operate in the "switched" mode, uplink signals received by all three of the antennas (Antenna 1 , Antenna 2 and Antenna 3) are still conveyed directly to their respective BTS radios (BTS Radio 1 , BTS Radio 2 and BTS Radio 3), and not all to a single radio as is the case for SSD 100 in the "switched" mode.
  • the SSD 400 depicted in Figure 17 differs from the SSD 200 depicted in Figure 15 in that, in the SSD 400, only the BTS radio 1 can be used as the transmission (Tx) source.
  • Figure 18 contains a schematic representation of the functional electronics and components used inside an SSD 500 in accordance with a fifth possible embodiment of the invention. It is important to note again that Figure 18 shows the functional electronics for only one of the two SSDs required by a given BTS.
  • the SSD 500 in Figure 18 has frequency conversion mixers associated with the BTS Radio 2 and the BTS Radio 3 to allow for possible frequency shifting.
  • duplexing In the context of cellular telecommunications at least, it should first be noted that it is essential, in any cellular communications system , for downlink and uplink transmissions to be able to occur simultaneously. This is essential, for example, because it enables spoken conversations to be made, with either end being able to talk and listen as required. Likewise, in relation to data transmission and exchange, it is often necessary to be able to undertake virtually simultaneous or completely simultaneous communications in both directions.
  • duplex scheme In order for a cellular telecommunications system (or indeed any radio communications system) to be able to communicate in both directions it is necessary to have what is termed a duplex scheme. There are several methods that can be adopted. For applications involving cellular telecommunications, where it is required that the base transceiver station (BTS) and also the user (UE) are able to operate (i.e. to transmit and receive) simultaneously, two schemes are commonly used: one is commonly known as “frequency division duplexing" (“FDD”), and the other is commonly known as “time division duplexing" (“TDD").
  • FDD frequency division duplexing
  • TDD time division duplexing
  • a FDD system i.e. a system in which frequency division duplexing is used
  • two distinct channels i.e. two distinct frequency bands
  • the uplink and downlink channels are assigned to different frequency bands respectively.
  • Each band is isolated from the other by means of (possibly amongst other things) duplexing filters in the front end of the base transceiver station.
  • a single channel i.e. only a single frequency band
  • distinct timeslots are allocated for transmission and reception.
  • a single frequency channel is used to transmit signals in both downlink and uplink directions, and this is made possible by assigning separate (possibly albeit not necessarily alternating) timeslots to transmit and receive operations. Filters may not be strictly necessary in TDD systems, except perhaps as a way of preventing out-of-band interference from external signal sources from entering the system and desensitising the base station receiver.
  • the SSD 600 in Figure 19 when the SSD is in the "Switched” mode, the antennas for all three sectors are connected to BTS Radio 1 , and BTS Radio 2 and BTS Radio 3 are placed into a shutdown state.
  • the sequence of steps that is followed in switching between the "Normal” mode and the "Switched” mode in the SSD 600 in Figure 19 is also identical to the SSD in (for example) the embodiment 100 described above.
  • the chief difference between the SSD 600 in Figure 19 and (as an example) the SSD in the embodiment 100 described above is that the SSD 600 in Figure 19 is a wideband device in which the downlink & uplink signals follow a common path between the input & output ports of the SSD.
  • the SSD 600 does not have (between the radio(s) and its respective antennas) separate transmission paths for downlink and uplink signals - i.e. within the SSD 600, uplink and downlink signals passing between the radio(s) and the antennas follow a common (i.e. uplink and downlink signals both follow the same) transmission path through the SSD 600.
  • the SSD 600 in Figure 19 is compatible with both FDD and TDD BTSs.
  • FIG. 20 An alternative SSD embodiment 700, which is also compatible with both FDD and TDD systems, is shown in Figure 20.
  • the SSD 700 in Figure 20 differs from the SSD 600 in Figure 19 in that the antennas from all three sectors can be connected to any one of BTS Radio 1 , BTS Radio 2 and BTS Radio 3 when the SSD 700 is in "Switched" mode, and the other two BTSs are placed into a shutdown state.
  • the configuration of the SSD 700 in Figure 20 provides the following potential benefits (possibly amongst others):
  • the SSD 700 can alternate (or allow alternation) between BTS Radio 1 , BTS Radio 2 and BTS Radio 3 from day to day (or from time to time), thereby potentially allowing wear and tear to be shared (or spread approximately evenly, etc) among multiple or all BTS Radios.
  • the components which make up the SSD and which provide its functionality will normally be housed/mounted within an enclosure or housing and typically the enclosure or housing will have (at least, or amongst other things) six coaxial connectors and a one AISG connector.
  • the AISG connector may be used to connect multiple SSDs installed on the mast of (or at some other location on or near) a BTS.
  • SSDs will be band specific. Each band may therefore have a different frequency SSD, with the frequency of the SSD being determined/characterised by the filters used within the SSD. Multiband base transceiver stations (BTSs) would therefore use SSDs of different frequencies to cater for the bands at that site.
  • Typical frequency bands on which Mobile communications operate include 700MHz, 850MHz, 900MHz, 1800MHz, 1900MHz, 2100MHz, 2300MHz, 2600MHz.
  • An SSD may also be capable of passing any AISG signals and also DC to each of an antenna's remote electrical tilt receivers.
  • AISG is a protocol specifically used to communicate with antennas. AISG signals may thus be passed through the SSD so that the antenna can also receive the AISG signals.
  • BTSs in a network that all use the frequencies ⁇ 1 ,2,3 ⁇ when in the "Normal" mode should not necessarily all switch to BTS Radio 1 (and its corresponding frequency ⁇ 1 ⁇ ) when in "Switched” mode, especially if they all switch to the "switched” mode at the same time. Instead, some BTSs should switch to BTS Radio 1 , others to BTS Radio 2, and the rest to BTS Radio 3.
  • the choice of which specific BTS Radio a BTS should use when in the "switched” mode depends on which configuration minimises the potential for inter-cell interference with other cells.
  • TMA Tower Mounted Amplifier
  • TMAs are bidirectional devices that are frequently employed in cellular BTSs to improve the noise figure of the BTS receiver. TMAs can also be useful in preventing external out-of-band interference signals from entering the system via the antenna and desensitising the BTS receiver. TMAs are designed to be inserted into the RF path between the BTS radio and the corresponding antenna, usually as close to the antenna as possible, and they are available for both FDD and TDD systems.
  • the SSDs in these embodiments have a duplexing filter at the BTS Radio and Antenna ports, and a low-noise amplifier in the uplink path.
  • the SSDs in these embodiments also have control modules equipped with AISG modems to allow the BTS to communicate with the SSD and instruct it to change its operating mode if necessary.
  • MIMO which stands for "multiple-input, multiple output”
  • MIMO is a method for multiplying the capacity of a radio link by using multiple transmit and receive antennas to exploit multipath propagation.
  • a MIMO scheme typically employs multiple antennae at the transmitter (e.g. multiple antennas may be provided for a single BTS sector) and also at the receiver (e.g. the user's mobile handset may also have multiple antennas) to enhance the data capacity achievable between the transmitter and the receiver.
  • a 2x2 "single user MIMO" (SU-MIMO) configuration contains two antennae at the transmitter (e.g. two antennas are provided for the single BTS sector that is serving a particular user) and two antennae at a single receiver (e.g. two antennas at a single user's mobile handset).
  • a 4x4 SU-MIMO configuration contains four antennae at the transmitter and four antennae at the single receiver that is in communication with the transmitter. There is no need for the transmitter and receiver to employ the same number of antennae.
  • a BTS in a wireless communication system will be equipped with more antennae in comparison with a UE, owing to differences in power, cost and size limitations.
  • so called "multi-user MIMO” (MU-MIMO) is often employed, and this involves a single BTS which is able to perform MIMO communication with multiple users (e.g. multiple user mobile handsets) at once.
  • the present invention, and embodiments thereof, and the technology of the SSD discussed above, may also be adapted to suit (or for use in) other applications such as, for example, public Wi-Fi hotspot systems, or in fact any multiple radio communication system that experiences traffic fluctuations over time.
  • Embodiments of the present invention overcome this problem because, in basic terms, the SSDs provide a hardware solution that enables the same outcome to be achieved (i.e. turning off individual radios at a BTS to save power during low-traffic periods) but without needing access to or the ability to control the underlying operating system/software of BTS equipment/hardware.
  • the SSDs are also retrofittable to existing BTSs with only minimal alteration to the existing BTS hardware, software, systems and infrastructure.
  • another major benefit of the SSDs is that they can be installed on any existing base transceiver station.
  • an SSD may also be fully autonomous - that is, able to perform and "act upon" its own measurements of local traffic levels.
  • An autonomous SSD may therefore not require network statistics or the like in order to determine when to "switch", etc. The significance of this should not be underestimated, particularly in the context of practical implementation and deployment of SSDs within existing cellular telecommunication network infrastructure, because the fact that an SSD is autonomous (and not reliant on information exchange from other network components, etc) may help to minimise disruption or the need for change to other parts of cellular network infrastructure during implementation.
  • SSDs in various embodiments may also be able to adapt to any size and type of base transceiver station - including by using multiple SSDs. Tower top or tower base transceiver stations can be accommodated. SSDs may also be scalable to suit any number of sectors. Usually there will be three sectors, but sometimes up to six sectored sites are used. In any case, SSD embodiments may be implemented regardless of the number of sectors per site.
  • SSDs may be switched automatically (as discussed in detail above), or alternatively manually, between the "normal” and “switched'Venergy saving states.
  • the switching thresholds and preferred functions can be tailored on a per site basis, according to the particular requirements, conditions, etc, at a particular site.
  • the SSDs allow BTS radios to be turned off when appropriate in order to save power.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

L'invention concerne un appareil destiné à être utilisé dans une station de base multi-secteurs. La station de base comprend une pluralité d'antennes de secteur et une radio de station de base pour chaque antenne de secteur. L'appareil est fonctionnel, si le niveau de trafic de la station de base est égal ou supérieur à un niveau de seuil, pour amener la station de base à fonctionner dans une première configuration dans laquelle : toutes les radios de station de base sont alimentées en énergie ; et des signaux de liaison descendante en provenance d'une radio de station de base sont transportés vers l'antenne de secteur correspondant à cette radio ; et si le niveau de trafic de la station de base est inférieur au niveau de seuil, pour amener la station de base à fonctionner dans une seconde configuration dans laquelle : au moins l'une des radios de station de base est éteinte ; et pour chaque antenne de secteur dont la radio de station de base est éteinte, des signaux de liaison descendante vers ladite antenne de secteur sont envoyés par une radio de station de base qui est alimentée en puissance.
PCT/AU2016/051085 2015-12-17 2016-11-11 Améliorations concernant un fonctionnement de station d'émetteur-récepteur de base (bts) dans des systèmes de télécommunication cellulaire Ceased WO2017100826A1 (fr)

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AU2015905248A AU2015905248A0 (en) 2015-12-17 Improvements relating to Base Transceiver Station (BTS) Operation in Cellular Telecommunication Systems
AU2015905248 2015-12-17

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019236689A1 (fr) 2018-06-08 2019-12-12 Commscope Technologies Llc Régulation automatique de puissance d'émission pour des points radio d'un réseau d'accès radio centralisé qui fournissent principalement un service sans fil à des utilisateurs situés dans une zone d'événement d'un lieu
US12309692B2 (en) 2020-02-05 2025-05-20 Elisa Oyj Energy saving management in communication networks

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US6584330B1 (en) * 2000-07-18 2003-06-24 Telefonaktiebolaget Lm Ericsson (Publ) Adaptive power management for a node of a cellular telecommunications network
US20090153264A1 (en) * 2007-12-17 2009-06-18 Nec Corporation Filter having switch function and band pass filter

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6584330B1 (en) * 2000-07-18 2003-06-24 Telefonaktiebolaget Lm Ericsson (Publ) Adaptive power management for a node of a cellular telecommunications network
US20090153264A1 (en) * 2007-12-17 2009-06-18 Nec Corporation Filter having switch function and band pass filter

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019236689A1 (fr) 2018-06-08 2019-12-12 Commscope Technologies Llc Régulation automatique de puissance d'émission pour des points radio d'un réseau d'accès radio centralisé qui fournissent principalement un service sans fil à des utilisateurs situés dans une zone d'événement d'un lieu
EP3804419A4 (fr) * 2018-06-08 2022-02-23 CommScope Technologies LLC Régulation automatique de puissance d'émission pour des points radio d'un réseau d'accès radio centralisé qui fournissent principalement un service sans fil à des utilisateurs situés dans une zone d'événement d'un lieu
US12309692B2 (en) 2020-02-05 2025-05-20 Elisa Oyj Energy saving management in communication networks

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