Self-organizing cell / sector for a radio base station site

Abstract

A radio base station (200, 300) has a plurality of primary sectors (202, 204, 206; 302, 304, 306) A self-organizing supplementary sector is provided, having at least one transceiver and a supplementary antenna (208, 210, 212; 308) defining a supplementary coverage sector and a controller (218; 318) configured to vary the supplementary coverage sector by controlling at least one radio coverage parameter of the at least one supplementary antenna.

Description

Self-organizing cell / sector for a radio base station siteTechnical Field

[0001] The present invention relates to a self-organizing cell / sector for use to inexpensively add new frequency resources on a radio base station (RBS) site of a wireless telecommunication network. More specifically, the present invention is concerned with a radio base station (RBS) having at least one primary antenna / cell / sector and at least one supplementary antenna / cell / sector that self-configures / self-organizes the direction of its coverage area in order to add new frequency resources as such to efficiently best serve radio terminal hotspots on the radio base station site geographical RF coverage footprint of a wireless telecommunication network.Background Art

[0002] Wireless telecommunication networks such as cellular radio networks offering service to mobile phones and other devices typically comprise a plurality of radio base stations (RBS), each of which has at least one antenna mounted thereon. Each antenna is connected to a transceiver to form a cell, and each cell covers a sector. A radio base station (RBS) comprising multiple sectors serves a predefined / predetermined geographical area (360° in the horizon) and is configured to provide radio communication services to several, typically mobile, radio terminal stations (RTSs) and / or radio terminal devices (RTDs).

[0003] By "sector" we mean a geographical area of a radio base station (RBS) site that is formed by the radiation characteristics of an antenna connected to a transceiver forming a cell in the field of cellular technology. A sector could operate on single band or multi frequency bands. The frequency bands are radio signals transmitted from and received by a transceiver. One or more sectors form the radio base station site geographical RF coverage footprint of a wireless telecommunication network.

[0004] Examples of radio terminal devices (RTDs) include cellular phones, smart phones, session initiation protocol (SIP) phones, laptops, notebooks, netbooks, smartbooks, personal digital assistants (PDAs), satellite radios, global positioning system (GPS) devices, multimedia devices, video devices, digital audio players (e.g., MP3 players), cameras, game consoles, Internet of Things (loT) devices or any other similar functioning device. The RTD is commonly referred to as user equipment (UE) in modern wireless technology networks such as LTE and 5G, but may also be referred to by those skilled in the art as a mobile station(MS), a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal (AT), a mobile terminal, a wireless terminal, a remote terminal, a handset, a terminal, a user agent, a mobile client, a client, or some other suitable terminology.

[0005] A radio terminal station (RTS) is defined as the device that connects with at least one network RBS cell to transfer data therebetween for radio signal re-transmission. The RTS may re-transmit RBS signals in a wired or wireless manner, in the initial form of the signal or other forms, to offer service to at least one RTD. In this mode, the RTS can serve as an intermediary between the RBS and the RTD. Alternatively, the RTS may be the endpoint itself (for example, the RTS may be any device using the network connection to browse the internet).

[0006] Examples of RTSs can be any of the aforementioned RTD's including but not limited to wireless modem / routers, internet bonding / bundling devices, signal repeaters and boosters, backhauling systems and the like. As mentioned, RTSs may be used as intermediaries between the wireless telecommunication network RBSs and the RTDs that are herein considered to always be the end-users of the network. An example of a smartphone used as an RTS is when a smartphone is set in wireless hotspot mode to offer WiFi (RTM) coverage to other smartphones, tablets, laptops and other RTDs in range. Another example is when a radio repeater / booster is used as an RTS in order to further retransmit the received RBS signals (donor RBS) using a single re-transmitting antenna or a distributed antenna system to offer (i.e., indoor) coverage to RTDs in range. A further example is when one or more cellular chip(s) / modem(s) is configured with a router and optionally with an internet bonding / bundling device to utilize the initial RBS signals in order to operate as a backhauling system for a plurality of indoor radio units such as Ericsson's radio dots (TM) or similar to offer wireless network coverage to a "hotspot".

[0007] By "hotspot" we mean a predefined geographical area containing multiple RTDs that are requesting service directly from a wireless telecommunication network or via an intermediary such as an RTS. Hotspots can be static (indoor or outdoor) or moving in the wireless telecommunication network coverage footprint. Examples of static indoor hotspots are homes, hotels, factories, in-building coffee shops, clubs, restaurants and the like. Examples of static outdoor hotspots are stadiums, beaches, outdoor coffee shops, clubs,restaurants and the like. Examples of moving hotspots are ships, buses, trains, tracks, cars and the like.

[0008] It is well known in the art that a wireless telecommunication network exploits its resources to the maximum (spectrum, radio base stations and general infrastructure), when the signal to noise and interference ratio (SINR) of the wireless connections between the RBS and the radio terminal stations and / or the radio terminal devices (RTSs / RTDs) in use are capable of supporting the highest possible values (i.e. 25dB or more). In order for the radio base station signal to be demodulated by the receiver of the RTS / RTD (this being the criterion for achieving network connectivity), it needs to be greater in power than the sum of the interference and noise / sensitivity of the RTS / RTD receiver (i.e., the minimum signal power that the receiver can distinguish the signal from the interference and noise and decode it). On radio link adaptation or similar wireless telecommunication technologies, signal to noise and interference ratio (SINR), on top of coverage also defines the capacity of the radio base station built. As such, the received signal strength level of the serving RBS cell as well as the received signal strength level of the neighbouring RBS cell(s) in the same geographical coverage footprint / area (as both define the SINR values experienced by the RTSs / RTDs requesting service in this coverage footprint / area) are of utmost importance for the radio base station coverage and capacity performance.

[0009] When designing radio base station coverage and dimensioning capacity for high performance service the main design objective is to achieve the highest positive SINR values (i.e. SINR > 25dB) for all radio links (ideally) that are to be established in the intended service area between the users requesting service (i.e. RTSs / RTDs) and the serving radio base station (RBS). However, especially on the RBS radio overlapping areas (such as handover areas), this is not the case. In radio frequency engineering, an overlapping area occurs when signals from two or more antennas / cells (of the same or different radio base station), transmitting at the same frequency, can be received with comparable strength / intensity. Such an area is considered as high interference area and the RTSs / RTDs requesting service on such areas suffer from low SINR values (i.e. SINR < 0). This is undesirable since radio links of low SINR values underutilize the network's channel bandwidth, offering the users low network performance service (if at all).

[0010] In an exemplary LTE technology radio network of 20MHz channel bandwidth, 29 different modulation and coding schemes (MCS) are supported, each requiring a different minimum signal to noise and interference ratio (SINR) at the receiver in order to achievetargeted bit rates (Table 1 ). The highest MCS (i.e. MCSI28) is attributed to radio links that meet the corresponding SINR level (i.e. SINR > 24.87dB), while for an SINR level that range between -3.98dB and -2.68dB, the network will support the lowest MCSI (i.e. MCSI 0). For SINR values of less than -3.98dB, this exemplary LTE wireless network does not offer any service. That is, in this case, for the same network resources (same spectrum / channel bandwidth), the change in service speeds / service (due to radio link performance) is huge. This change depends solely on the levels of received signal power from the serving RBS, the levels of the received interference from the neighbouring RBS(s) to the RTS / RTD in use (and of course the noise figure of the RTS / RTD receiver itself).

[0011] Handover areas are usually located at the coverage-edge (usually called as celledge) of 2 or more radio base station antennas / cells. However, irrespective of the radio pathloss that these 2 or more radio base station antennas / cells have from the RTS / RTD (low or high), their signals are received at nearly equal strengths (overlapping). This is the reason that RTSs / RTDs located at a radio base station handover area inherently suffer from low SI NR values (i.e. SI NR < 0). Assuming that a point to multi-point wireless telecommunication network is designed for mobility, such as LTE and 5G (in frequency re-use patterns that do not allow coverage gaps), overlapping for 2 or more radio base station antennas / sectors (such as handover areas) are intentionally allowed on the network by radio engineers. To satisfy uninterrupted network coverage for high-speed mobility (e.g. car, bus, truck, train, ship and the like), overlapping between radio base station antennas could even be over 30%. This means that if the RTS / RTD is geographically located either on a vehicle moving between radio base station antenna / cell coverage areas (i.e. a passenger ship) or it is stationary inside their overlapping areas (i.e. a hotel), the terminal devices served in these areas will be experiencing low SI NR values (SI NR < 0) irrespective of the signal strength they may be receiving from the serving radio base station. This is undesirable since for low SINR values, low MCS can be achieved (if at all), and thus low data bit rates can only be offered from this network to the RTS / RTD in use.

[0012] It should be noted that for most wireless broadband technologies, the radio base station available channel bandwidth is equally shared between all users requesting service from the radio base station cell in its dominant area of service (a cell is considered dominant or best serving in the service area when its signal strength is higher than its neighbours). The radio base station scheduler is responsible for sharing the channel bandwidth between the users according to their application needs. Therefore, each RTS / RTD requesting service from the radio base station cell, has to achieve the best possible radio link conditions (i.e.optimum SINR values offer connectivity of higher I highest order MCS) in order to make optimum use of the offered radio resource from the radio network (the minimum radio resource in an LTE network is a single physical resource block or PRB per 1 ms time or TTI). In case that SINR is sub-optimum, radio link will adapt to lower modulation and coding schemes that in turn offer lower throughput speeds (or data transfer rates) per assigned physical resource. As such, radio links of sub-optimum SINR values transfer data slower on the network's finite network physical resources (i.e. a 20MHz channel bandwidth in LTE has just 100 PRB / TTI) leading to high data transfer delays for all users served (or even the so called network congestion, especially under high RBS traffic conditions).

[0013] The ultimate objective of radio engineering is to achieve radio base station coverage areas that offer to all users requesting service SINR values that can offer the RTS / RTD connections with the highest possible modulation and coding schemes (i.e., a radio link that achieves MCS of 256-QAM may be considered that makes ultimate use of the radio resource). Of course, such an objective, although ultimate, cannot always be technically (and financially) feasible. Either the coverage area characteristics (i.e., the clutter), the imperfect radio equipment (i.e. the antennas), the mobility of user / usage inside the coverage area, or even the available RBS network roll-out and implementation budgets, turns the radio engineering objective from ultimate to best effort. Therefore, although radio designs should be aiming to achieve radio base station coverage areas that may offer the highest possible modulation and coding schemes to all users, they settle to radio designs that built coverage areas of best effort SINR / MCS for the majority of them (not all) served in the coverage area.

[0014] Turning to a realistic network deployment, consider the popular radio base station 3-sector / cell radio design (antennas heading on different - usually 120° offset to each other - but fixed directions). Such an example, where an RBS 10 having three sectors 12a, 12b, 12c equipped with antennas of the same radiation pattern, is shown in Figure 1 . The plot is polar with r=dB, the outer radius representing maximum antenna gain (and therefore maximum signal strength receptions at the RTD / RTS receiver towards these directions when assuming for 360°the same RE propagation losses / radio propagation environment).

[0015] In such deployments (3-sector / cell), the antennas used are of the same 60° horizontal half-power beamwidth (-3dB) and of equal gain (usually the same type of antennas).

[0016] A close look at the radiation pattern of such an antenna will show us that the maximum gain in the horizontal plane is at 0° heading (max gain) - see point 250. The signal strength drops at an offset of ±30° by 50% (max-3dB gain, or half-power beamwidth) at point 252a. At an offset of ±60° the gain drops further 1 Ox (max-1 OdB gain) (point 254), while the gain drops even further as we move away from ±60° (i.e. 180° or back heading has usually max-25dB gain). Such imperfections on the antenna radiation pattern (gain variability in the H / V-plane), especially when the antennas are used in pairs 360° around the RBS site, causes wide overlapping areas between the antenna / cells of the same radio base station. This is shown in Figure 1 .

[0017] Maximum gain is provided in-line with each antenna (i.e. at the centre of each sector 12a, b, c) or at 120 degree intervals. The first path of maximum gain is shown at 14 (where SINR is a maximum). Between each of these paths (e.g. at path 16), the SINR is null. 15 degrees either side of the path 16, in zone 18 the SINR is between OdB and 10dB. Therefore for 25% of the coverage area (3 x ±15° = 90 degrees in total), the SINR is <1 OdB. In other words, 25% of the users served (when assuming equal traffic distribution 360° around the radio base station site) cannot achieve higher order modulation and coding schemes (i.e. on a radio link adaptation technology such as LTE, modulation and coding scheme will be QPSK or 16-QAM at best). As such, the popular radio base station 3-sector / cell radio designs, inherently suffers degraded capacity and performance due to their own overlapping radio areas.

[0018] Assume now that the traffic distribution is not equal 360° around the RBS site and that the radio engineers have properly identified and geo-located the areas of high traffic generation as well as planned and implemented each antenna / cell of the radio base station towards the correct horizontal and vertical direction. Any users geo-located in the RF overlapping areas, will be degrading the total radio base station capacity performance. When the number of users in such overlapping areas increases, the degradation of the RBS capacity becomes significant. This is due to the fact that channel bandwidth utilization, especially for fair-sharing scheduler types (if there is more than one user, the scheduler shares radio resources equally between users, independently of the radio conditions that each user is experiencing), is severely impacted due to the fact that there is a high number of low order MCS physical resource occupancy on the serving RBS channel bandwidth. As such, the high number of users served in overlapping areas occupy for longer times the RBS physical resources (due to lower data transfer speeds) leading to low RBS capacity especially under high traffic conditions. This is undesirable since when there is a hotspot(permanent, sporadic or ad-hoc in time) on a radio overlapping geographical area it may lead to the so-called network congestion for all users served from the dominant / best serving cell in this area or they will be underserved.

[0019] It is known by those skilled in the art that there are times (discrete times during the day and / or specific days during the week) that radio base station overlapping areas present high traffic demand. Sometimes traffic in the overlapping areas is even higher than in the dominant / high SI NR antenna / cell coverage areas.

[0020] In an exemplary 24 / 7 / 365 RBS traffic distribution, a high traffic road is present on an overlapping area of sector 12a and sector 12b of the same radio base station 10. The road becomes busy on weekdays from 7:30am to 9:30am and from 4:30pm to 6:30pm. A high traffic office building is present in the overlapping area of sector 12a and sector 12c of RBS 10. This becomes busy on weekdays for 7-hours from 9:30am to 4:30pm). A high traffic golf course is present in the overlapping area of sector 12b and sector 12c of the same radio base station. It is busy on Sundays from 9:30am to 7:30pm.

[0021] At all othertimes and days of the week, no significant mobile data traffic is generated on the overlapping areas of the exemplary 3-sector radio base station 10.

[0022] In another example, a passenger ship (mobile hotspot) travels on a sea-route that is located on the overlapping areas of adjacent sectors of the same radio base station for 30 minutes every day of the week, for all weeks of the year. In further example, a super-yacht appears ad-hoc on the same sea-route for 15 minutes. Assuming that the passenger ship is a Ro-Pax ferry carrying 2000 passengers (a high mobile network user / usage hotspot), where 50% of these passengers register on the same RBS (1000 passengers), while just 10% of those (100 passengers) simultaneously request video streaming services (a high data throughput need application) from the RBS dominant / serving cell. All 100 passengers on the Ro-Pax ferry will congest the RBS cell (i.e. the network speed on offer does not match the demand for such application coverage) when travelling in its RF overlapping area. This is undesirable since all users requesting service from the specific cell will encounter network outage when this cell is dominant for the passenger ship at its overlapping area.

[0023] The applicant's prior application WO 2015 / 197324 provides a method of determining the optimum radio planning parameter of an antenna azimuth heading. The invention of that application operates by firstly providing network performance data from the radio base station to a central control system. This data is provided per sector, at 3different azimuth headings (0° and ±15° for example). The data is provided in terms of KPIs (key performance indicators). The antenna is adjusted to the heading that provide the best performance (in terms of selected network KPIs) towards high traffic in the sector's overlapping areas. Although this process successfully optimizes SINR towards the areas where traffic is generated, in high traffic cases is considered inadequate since the radio resource (i.e. channel bandwidth) on offer remains limited. Further, such an SINR optimization method disclosed on WO 2015 / 197324 focusses on one overlapping area at any one time, and does not account for the fact that the traffic demand may also be high at all cell dominance coverage area at the same time.

[0024] To improve RBS capacity and performance by increasing its available channel bandwidth in the coverage area, while improving the SINR for most users served, the current radio base station designs should increase sectorization (i.e. from 3-sectored into 4 or more sectored configurations). However, although the high traffic users on the overlapping areas (users with bad SINR) with such cell additions would be greatly reduced (assuming proper / targeted radio planning), while the total RBS channel bandwidth would be substantially improved, such a radio design decision is not financially desirable for the network operator since RBS cell additions significantly increase the network's capex and opex. As such, especially when the need is to serve sporadic or ad-hoc high mobile traffic in the RBS overlapping areas, performing such cell additions is unprofitable forthe network operator and the sectors are usually left untouched for most of the time. Conversely, doing nothing for the sporadic or ad-hoc high mobile traffic in the overlapping areas leads to network outage or bad service experience. Both are undesirable.

[0025] It is an aim of the present invention to overcome these problems.Summary of Invention

[0026] According to a first aspect there is provided a radio base station site comprising: a plurality of primary sectors each having at least one primary transceiver and defining a primary coverage area; a self-organizing supplementary coverage sector comprising: at least one supplementary transceiver; at least one supplementary antenna; and,a controller configured to vary the supplementary coverage sector by controlling at least one radio coverage parameter of the at least one supplementary antenna.

[0027] By "self-organizing" we mean that the sector or sectors are controlled in an automatic manner without direct human intervention.

[0028] By "transceiver" we mean a radio transmitter and receiver, responsible for sending and receiving radio signals over one or more radio frequency bands. Each transceiver on a radio base station site operates independently forming an RF coverage cell or sector. Therefore, the present invention features a directional antenna whose properties (e.g. radiation directionality and radiated power) can be varied, but also represents a new RF cell or sector area in the radio base station site geographical RF coverage footprint - i.e. adds new frequency resources in the radio base station site geographical RF coverage footprint. The transceiver may be e.g. a nodeB, an eNodeB, a gNodeB or similar depending on wireless telecommunication technology. In practical terms, the supplementary sector has a common site ID (SID) with the primary sectors, but a unique cell ID (CID), physical cell ID (PCI) and sector name.

[0029] The supplementary coverage sector at least partially overlaps in coverage area with at least one of the primary sectors, to supplement coverage in that area. By "vary the sector" we mean vary the location and / or area shape of the coverage area of the supplementary sector.

[0030] By radio coverage parameter we mean any, of the following:• the antenna orientation (azimuth or elevation);• the antenna radiation pattern (i.e. horizontal / vertical half-power beamwidth);• the transmitting power level (for the connected transmitters);• the receiver sensitivity level (for the connected receivers);

[0031] The supplementary antenna may provide electrical and / or electromechanical beam downtilt and uptilt capability.

[0032] Preferably the supplementary antenna transmits higher power than the primary antennas. For example, the supplementary antenna transmitters could be set to 40W transmitting power when the primary antenna transmitters are set at 20W transmittingpower (this may require coordination with various elements in the radio base station network architecture).

[0033] Preferably the supplementary antenna receiver may have improved receiver sensitivity than the primary antennas' receivers. For example, the supplementary antenna receiver could be deployed with an additional external LNA (low noise amplifier) in-line.

[0034] Advantageously, this flexible, supplementary system allows radio coverage to be improved without significant capital and operational investment in further RBS cell / sector / nodes or (in one embodiment) antennas. The invention provides a way of enhancing coverage to those areas that need it, without excessive increases in capital and operational expenditure. Unlike the prior art document WO 2015 / 197324, the present invention directly adds capacity (by adding new frequency resource) to the radio base station site geographical RF coverage footprint in question.

[0035] In one embodiment, the supplementary antenna is steerable and the controller is configured to vary the azimuth heading of the supplementary coverage area by steering the supplementary antenna. Preferably the supplementary antenna is steerable about 360 degrees. The supplementary antenna may be directed towards an area of overlap of two adjacent primary antennas, which is typically where the SINR can be lowest. Preferably the supplementary antenna is positioned above or below the plurality of primary antennas, on the same or different mounting bracket.

[0036] In an alternative embodiment, there is provided a plurality of supplementary antennas each defining a different coverage area and a switch for alternating a connection between each antenna of the plurality, and a node; wherein the controller is configured to vary the supplementary coverage area by controlling the switch to switch between the supplementary antennas. Advantageously, by using multiple high power RF switched antennas, the number of eNodeB's serving these antennas is greatly reduced (i.e. one eNodeB is required for all supplementary antennas), as such the RBS capital and operational investment is significantly reduced.

[0037] These two embodiments may be combined to form a third embodiment in which multiple supplementary antennas are provided, which can be steered individually, and which can be switched as required. For example, each of three antennas may have a narrow beam steerable across 120 degrees. The controller is therefore able to switch to an appropriate antenna, and steer it to a desired direction to provide the supplementary RFcell or sector within the radio base station site geographical RF coverage footprint as required.

[0038] Preferably the primary coverage area defines a plurality of primary sectors in different azimuth directions, and wherein the supplementary sector(s) is positioned between adjacent primary sectors.

[0039] Preferably the maximum gain of the at least one supplementary sector antenna is higher than the gain of each of the plurality of primary sector antennas towards their maximum-1 OdB horizontal heading wrt to their 0° heading (maximum gain). This provides that the supplementary sector coverage area is dominant in terms of signal strength, providing the same radio propagation environment towards the same azimuth heading with respect to North with the primary sector(s).

[0040] More preferably the gain of the at least one supplementary sector antenna is XdB higher than the gain of each of the plurality of primary sector antennas towards the same azimuth heading with respect to North. This provides that the supplementary coverage area is optimized by XdB in terms of signal to noise and interference ratio (SINR), providing the same radio propagation environment towards the same azimuth heading with respect to North with the primary sector(s).

[0041] Preferably the horizontal half-power beamwidth (-3dB) of the at least one supplementary sector antenna is less than the horizontal half-power beamwidth (-3dB) of each of the plurality of primary sector antennas. This provides that the supplementary coverage area is narrow enough as such to become dominant mainly for the hotspot present in the overlapping area. For example, the hotspot may be a relatively small area (say a 200m length Ro-Pax ferry) at a distance from the RBS of 1 km. Only 5° of horizontal half power beamwidth would be required to best serve such an area at such distance.

[0042] More preferably the horizontal half power beamwidth of the at least one supplementary antenna is electrically controlled (i.e. by using a beamforming antenna type). This provides that the supplementary coverage area created by the electrically controlled radiation pattern best serves the hotspot (size of the hotspot at the specific distance from the RBS location) in the coverage area (i.e. alternating the half power horizontal beamwidth from i.e. wide to narrow depending on the size of the hotspot at the specific distance from the RBS location).

[0043] Even more preferably, the supplementary antenna is multiband, MIMO, massive- MIMO, beamforming, active or passive antenna.

[0044] In one embodimentthe controller is configured to vary the supplementary coverage areas based on at least time of day. In the switching embodiment, the antenna selected is based on the time of day. In the steering embodiment, the antenna direction is selected based on the time of day.

[0045] The controller may be configured to vary the supplementary coverage areas based on demand. In the switching embodiment, the antenna selected is based on demand. In the steering embodiment, the antenna direction is selected based on demand.

[0046] The controller may be configured to vary the supplementary coverage areas based on the presence of a specific RTD or RTS in the coverage area. In the switching embodiment, the antenna selected is based on a specific RTD or RTS in the sector. In the steering embodiment, the antenna direction is towards the RTD or RTS in question.

[0047] In the case of steering, the system of the present invention utilises antenna control. By antenna control we mean that the antenna(s) may automatically change any or all of their radio planning parameters (i.e. horizontal or vertical half-power beamwidth, transmitted power, azimuth and elevation direction) under a pre-defined specified condition. For example, there may be only direction control of the main beam towards a specified offset (i.e. a designated (VIP) radio terminal device is in the coverage area of the self-organizing radio base station, or a self-organizing radio base station designated coverage area is heavily populated by radio terminal devices during a time of a day / a day of a week). Control of the main beam direction takes place locally, remotely or both. Local control means that an azimuth beam-steered antenna system has built-in a 24 / 7 / 365 azimuth targeting pattern. Remote control means that the azimuth beam-steered antenna system is remotely instructed by a central server to azimuth target towards a designated coverage area or towards the coordinates of a specific RTD / RTS.

[0048] An exemplary 24 / 7 / 365 azimuth targeting pattern (local control operation) could be the azimuth beam-steered antenna system to target towards a main road Monday to Friday for 2-hours from 7:30am to 9:30am and for another 2-hours the same day from 4:30pm to 6:30pm. In a different time period, Monday to Friday and for 7-hours from 9:30am to 4:30pm the azimuth beam-steered antenna system is targeted towards an office building. On a different day, Sunday for 10-hours from 09:30am to 7:30pm a golf course is targeted.

[0049] All other times and days of the week it will either switch off, minimize its transmitted power(functionalities that may require coordination with various elements in the radio base station network architecture) or will head to a pre-defined azimuth direction.

[0050] In another exemplary configuration, the azimuth beam-steered antenna system is remotely instructed by a central server to azimuth target (remote control operation) towards i.e. a passenger ship (VIP-hotspot) or a super-yacht (VIP-terminal) sailing on a sea-route that is on the coverage area of the azimuth beam-steered antenna system. The central server receives the location of the VIP in real-time, calculates the required heading of the antenna and instructs the azimuth beam-steered antenna system to target towards the VIP direction.

[0051] In a different exemplary configuration, the azimuth beam-steered antenna system operates on a combination of a 24 / 7 / 365 azimuth targeting pattern and on remote instructions by a central server.

[0052] The primary coverage area may be invariant, or alternatively the at least one primary antenna may be moveable to vary the primary coverage sector. The movement range of the at least one primary antenna is typically less than the movement range of the supplementary antenna. For example, the primary antenna may be moveable by ±15 degrees or less, and the supplementary antenna by 360 degrees.

[0053] The controller may be configured to switch the supplementary coverage sector on and off, for example to meet demand when required and to conserve power when not required.

[0054] According to a second aspect there is provided a method of operating a radio base station site comprising the steps of: providing: a plurality of primary sectors each having at least one primary transceiver and defining a primary coverage area; a self-organizing supplementary coverage sector comprising at least one supplementary transceiver and at least one supplementary antenna; varying the supplementary coverage sector by controlling at least one radio coverage parameter of the at least one supplementary antenna.

[0055] Preferably the at least one radio coverage parameter includes at least one of the following: azimuth orientation of the supplementary antenna; elevation orientation of the supplementary antenna; the radiation pattern of the supplementary antenna; the transmitting power level of the supplementary antenna; and, the receiver sensitivity level of the supplementary antenna.

[0056] Preferably the method comprises the step of: varying the azimuth heading of the supplementary coverage area by steering the supplementary antenna.Preferably the method comprises the step of directing the azimuth heading of the supplementary antenna towards an overlapping area of two adjacent primary antennas.

[0057] Preferably the method comprises the step of: providing: a plurality of supplementary antennas each defining a different coverage area; and, an RF switch for alternating a connection between each antenna of the plurality, and a network node; varying the supplementary coverage sector by controlling the RF switch to switch the network node connection between the supplementary antennas.

[0058] Preferably the primary RF coverage area defines a plurality of primary RF sectors in different azimuth directions, and wherein the supplementary RF coverage area is positioned between adjacent primary RF sectors.

[0059] Preferably the method comprises the step of varying the supplementary coverage sectors based on at least time of day.

[0060] Preferably the method comprises the step of varying the supplementary coverage areas based on demand.

[0061] Preferably the method comprises the step of varying the supplementary coverage areas based on the presence of a specific RTD or RTS in the coverage area.

[0062] Preferably the method comprises the step of moving the at least one primary antenna to vary the primary coverage sector.Brief Description of Drawings

[0063] An embodiment of the present invention will now be described with reference to the following figure in which:FIGURE 1 is a simplified plan view of coverage based on radiation patterns emerging from radio base station antennas / cells / sectors;FIGURE 2a is a schematic view of a radio base station equipped with a first apparatus in accordance with the present invention;FIGURE 2b is a schematic view of the first apparatus of Figure 2a;FIGURE 3a is a schematic view of a radio base station equipped with a second apparatus in accordance with the present invention;FIGURE 3b is a schematic view of the first apparatus of Figure 3a; and,FIGURE 4 is a schematic view of a radio base station equipped with a third apparatus in accordance with the present invention.Description of the first embodimentConfiguration

[0064] Referring to Figures 2a & 2b, a radio base station (RBS) 200 in accordance with the present invention is shown. The radio base station 200 comprises three primary antennas 202, 204, 206, each of which has a radiation pattern in the form of sectors 202a, 204a, 206a. The RBS 200 is configured to provide cellular coverage to RTSs and RTDs in its service area.

[0065] Referring to Figure 2b, each antenna 202, 204, 206 is connected to a respective transceiver e.g. an eNodeB (for 4G) 202b, 204b, 206b to provide a two way wirelessconnection for service. Therefore a cell is formed by (for example) the antenna 202, transceiver 202b. This cell covers the sector 202a.

[0066] Three further (supplementary) antennas 208, 210, 212 are provided between the antennas 202, 204, 206. Each antenna has a radiation pattern 208a, 210a, 212a.

[0067] The further antennas 208, 210, 212 have a radiation pattern 208a with an horizontal half-power beamwidth (-3dB) significantly less than the horizontal half-power beamwidth (- 3dB) of the radiation patterns 302a, 304a, 306a. By "significantly less" we mean less than 50%, and more preferably less than 25%. In this embodiment, the antenna has a narrow half-power beamwidth in the horizontal plane, and a wide half-power beamwidth in the vertical plane to account for variable positions of the RTDs / RTSs (i.e. distance and height of the RTDs / RTSs from the RBS location). The narrow horizontal half-power beamwidth is clearly visible in Figure 2a.

[0068] Referring to Figure 2a, the gain of the radiation patterns 208a, 210a, 212a is XdB greater than the gain of each of the basic antennas 202, 204, 206 (i.e. -10dB from their maximum atthis point). This means that the antennas 208, 210, 212 will be dominant servers in this area (assuming that the transmitted power and RF propagation losses are the same for all antennas serving this area).

[0069] Referring to Figure 2b, each antenna 208, 210, 212 is connected to a high-power RF switch 214 configured to selectively connect one of the individual antennas 208, 210, 212 to an eNodeB (for 4G) 216 to provide a two way data connection for service. The RF switch 214 is connected to a controller 218. As such, each of the antennas 208, 210, 212 can alternately form a cell with the transceiver 216 to service a respective sector 208a, 210a, 212a.

[0070] The nodes 202b, 204b, 206b, 216 are connected to a network 217.Use

[0071] In use, the controller 218 is configured to control the RF switch 214 to connect an appropriate antenna 208, 210, 212 to the eNodeB 216. The selection of the antenna 208, 210, 212 is based on the requirements of the network. In one example, this may be the presence of a hotspot in the coverage area of the selected antenna 208.

[0072] In one scenario, a "VIP" RTD 220 is provided at a location to be served by the RBS 200. In this instance, the controller 218 is provided with the location of the device 220 relative to the RBS 200 and as such can connect an appropriate antenna (in this case 210) to provide coverage to the RTD 220.

[0073] The system offers both local and remote control.

[0074] One antenna (out of the supplementary plurality) connects to the eNodeB (using the RF switches) every time is instructed from the controller.

[0075] An exemplary 24 / 7 / 365 azimuth targeting pattern (local control operation) could be:• the antenna system to target towards a main road Monday to Friday for 2-hours from 7:30am to 09:30am; and,• for another 2-hours the same day from 16:30pm to 18:30pm.• On a different time period, Monday to Friday and for 7-hours from 9:30am to 16:30pm the antenna system to target towards an office building.• On a different day, Sunday for 10-hours from 09:30am to 19:30pm to target a golf course.

[0076] All other times and days of the week it will either switch-off or minimize its transmitted power (may require coordination with various elements in the radio base station network architecture).

[0077] The controller 218 and RF switch 214 can therefore offer a time-dependent coverage and capacity boost whilst keeping the required amount of equipment(specifically the cap-ex and op-ex intensive nodes 216) to a minimum.Description of the second embodimentConfiguration

[0078] Referring to Figure 3a to 3b, a radio base station 300 in accordance with the present invention is shown. The radio base station 300 comprises three primary antennas 302, 304, 306, each of which has a radiation pattern 302a, 304a, 306a.

[0079] Referring to Figures 3b, each antenna 302, 304, 306 is connected to a respective transceiver e.g. an eNodeB (for 4G) 302b, 304b, 306b to provide a two way wireless connection for service. Therefore a cell is formed by (for example) the antenna 302, transceivers 02b. This cell covers the sector 302a.

[0080] A further, steerable, supplementary, directional antenna 308 is provided. Referring to Figure 3b, the antenna 308 comprises an actuator 310 having a steering shaft centred on, and steerable about, a vertical (azimuth) axis Z. The antenna 308 is steerable 360 degrees about X. The actuator is controlled by a controller 318 (Figure 3b). The antenna is connected to an eNodeB (for 4G) 308b. The controller 318, actuator 310 and antenna 308 form a self-organising system according to the present invention. The antenna 308 forms a cell with the transceiver 308b to service a sector 308a.

[0081] The nodes 302b, 304b, 306b, 308b are connected to a network 31 7.

[0082] The steerable antenna 308 has a radiation pattern 308a with a horizontal half-power beamwidth (-3dB) significantly less than the horizontal half-power beamwidth (-3dB) of the radiation patterns 302a, 304a, 306a. By "significantly less" we mean less than 50%, and more preferably less than 25%. In this embodiment, the antenna has a narrow -3dB beamwidth in the horizontal plane, and a wide -3dB beamwidth in the vertical plane to account for variable positions of the RTDs / RTSs (i.e. distance and height of the RTDs / RTSs from the RBS location). The narrow horizontal beam width is clearly visible in Figure 3a.

[0083] Referring to Figure 3a, the gain ofthe radiation pattern 308a is XdB greater than the gain of each of the basic antennas 302, 304, 306 towards the same direction (i.e. -10dB from their maximum at this point). This means that the antenna 308 will be the dominant server in this area (assuming that the transmitted power and RF propagation losses are the same for all antennas serving this area).Use

[0084] In use, the controller 318 is configured to control the actuator 310 to steer the antenna 308 based on the requirements of the network (i.e. the presence of a hotspot on their coverage area).

[0085] In one scenario, a "VIP" RTD 320 is provided at a location to be served by the RBS 200. In this instance, the controller 318 is provided with the location of the device 320relative to the RBS 300 and can steer the directional antenna 308 towards it to provide dominant coverage to the RTD 320.

[0086] The system offers both local and remote control.

[0087] Local control means that the azimuth beam-steered antenna system has built-in a 24 / 7 / 365 azimuth targeting pattern into controller 318. Remote control means that the azimuth beam-steered antenna system controller 318 is remotely instructed by a central server to azimuth target towards a designated coverage area.

[0088] An exemplary 24 / 7 / 365 azimuth targeting pattern (local control operation) could be:• the azimuth beam-steered antenna system to target towards a main road Monday to Friday for 2-hours from 7:30am to 09:30am; and,• for another 2-hours the same day from 16:30pm to 18:30pm.• On a different time period, Monday to Friday and for 7-hours from 9:30am to 16:30pm the azimuth beam-steered antenna system to target towards an office building.• On a different day, Sunday for 10-hours from 09:30am to 19:30pm to target a golf course.

[0089] All other times and days of the week it will either switch-off or minimize its transmitted power (may require coordination with the radio base station).

[0090] The controller 318 can therefore offer a time-dependent coverage and capacity boost whilst keeping the required amount of equipment (specifically the cap-ex and op-ex intensive nodes 308b) to a minimum.Description of the third embodimentConfiguration

[0091] Referring to Figure 4, a radio base station 400 in accordance with the present invention is shown. The radio base station 400 comprises three primary antennas 402, 404, 406, each of which has a radiation pattern per the first or second embodiment.

[0092] Each antenna 402, 404, 406 is connected to a respective transceiver e.g. an eNodeB (for 4G) 402b, 404b, 406b to provide a two way wireless connection for service. Therefore a cell is formed by (for example) the antenna 402, transceiver 402b. This cell covers the sector 402a.

[0093] Three further, steerable, directional antennas 408, 410, 412 are provided. Each antenna 408, 410, 412 comprises an actuator having a steering shaft centred on, and steerable about, a vertical (azimuth) axis. Each antenna 408, 410, 412 is steerable 120 degrees to provide an overall coverage of 360 degrees. The actuators are controlled by a controller. The antennas are connected to common transceiver in the form of an eNodeB (for 4G) 416, via an RE switching unit 414. The controller 418, switch 414 and steerable antennas 408, 410, 414 form a self-organising system according to the present invention.

[0094] The nodes 402b, 404b, 406b, 416 are connected to a network 41 7.

[0095] Each steerable antenna has a radiation pattern with a horizontal half-power beamwidth (-3dB) significantly less than the horizontal half-power beamwidth (-3dB) of the primary radiation patterns. By "significantly less" we mean less than 50%, and more preferably less than 25%. In this embodiment, the antenna has a narrow -3dB beamwidth in the horizontal plane, and a wide -3dB beamwidth in the vertical plane to account for variable positions of the RTDs / RTSs (i.e. distance and height of the RTDs / RTSs from the RBS location).

[0096] The gain of the radiation patterns of the supplementary antennas is XdB greaterthan the gain of each of the primary antennas 402, 404, 406 towards the same direction (i.e. - 10dB from their maximum at this point). This means that the antennas 408, 410, 412 will be the dominant server in this area (assuming that the transmitted power and RE propagation losses are the same for all antennas serving this area). As such, each of the antennas 408, 410, 412 can alternately form a cell with the transceiver 416 to service a respective sector (not shown).Use

[0097] In use, the controller 418 is configured to switch between the antennas 408, 410, 412 in terms of their connection to the transceiver 416. Only one antenna 408, 410, 412 is connected at a time. The controller 418 can also control the antenna actuator to steer theactive supplementary antenna based on the requirements of the network (i.e. the presence of a hotspot on their coverage area).Variations

[0098] The primary sectors of the above embodiments may be stationary (as described) or may be moveable. For example, the sectors may be moveable in accordance with WO 2015 / 197324, in which case the new supplementary sector increases performance overthat piece of prior art.

[0099] The RBS incorporating a system according to the invention may be mounted on an antenna mounting bracket, a camouflaged mast, on a lattice mast, on a guyed mast, on a utility pole, or on the rooftop of a building.

Claims

Claims1 . A radio base station site comprising: a plurality of primary sectors each having at least one primary transceiver and defining a primary coverage area; a self-organizing supplementary coverage sector defining a supplementary coverage area, the supplementary coverage sector comprising: at least one supplementary transceiver; at least one supplementary antenna; and, a controller configured to vary the supplementary coverage sector by controlling at least one radio coverage parameter of the at least one supplementary antenna.

2. A radio base station according to claim 1 , wherein the at least one radio coverage parameter includes at least one of the following: azimuth orientation of the supplementary antenna; elevation orientation of the supplementary antenna; the radiation pattern of the supplementary antenna; the transmitting power level of the supplementary antenna; and, the receiver sensitivity level of the supplementary antenna.

3. A radio base station according to claim 2, wherein: the supplementary antenna is steerable; and, the controller is configured to vary the azimuth heading of the supplementary coverage area by steering the supplementary antenna.

4. A radio base station according to claim 3, wherein the azimuth heading of the supplementary antenna is directed towards an overlapping area of two adjacent primary antennas.

5. A radio base station according to claim 3 or 4, wherein the supplementary antenna is steerable about 360 degrees.

6. A radio base station according to claim 1 , comprising:a plurality of supplementary antennas each defining a different coverage area; and, an RF switch for alternating a connection between each antenna of the plurality, and a network node; wherein: the controller is configured to vary the supplementary coverage sector by controlling the RF switch to switch the network node connection between the supplementary antennas.

7. A radio base station according to claim 6, wherein: each of the plurality of supplementary antennas is steerable; and, the controller is configured to vary the azimuth heading of the supplementary antennas.

8. A radio base station according to claim 6 or 7, wherein the primary RF coverage area defines a plurality of primary RF sectors in different azimuth directions, and wherein the supplementary RF coverage area is positioned between adjacent primary RF sectors.

9. A radio base station according to any preceding claim, wherein the horizontal halfpower beamwidth of the at least one supplementary antenna is narrower than the halfpower beamwidth of each of the plurality of primary antennas.

10. A radio base station according to claim 9, wherein the horizontal half-power beamwidth of the at least one supplementary antenna is less than 25% of the half-power beamwidth of each of the plurality of primary antennas.1 1. A radio base station according to any preceding claim, wherein the supplementary antenna transmits higher power than the primary antennas at at least one azimuth heading.

12. A radio base station according to claim 1 1 , wherein the supplementary antenna transmits higher power than the primary antennas at all azimuth headings within a range of movement of the supplementary antenna.

13. A radio base station according to any preceding claim, wherein the supplementary antenna receiver has improved receiver sensitivity compared to the receiver of each of the primary antennas.

14. A radio base station antenna apparatus according to any preceding claim, wherein the controller is configured to vary the supplementary coverage sectors based on at least time of day.

15. A radio base station according to any preceding claim, wherein the controller is configured to vary the supplementary coverage areas based on demand.

16. A radio base station according to any preceding claim, wherein the controller is configured to vary the supplementary coverage areas based on the presence of a specific RTD or RTS in the coverage area.1 7. A radio base station according to any preceding claim, wherein the primary coverage sectors are invariant.

18. A radio base station according to any of claims 1 to 16, wherein at least one primary antenna is moveable to vary the primary coverage sector.

19. A radio base station according to claim 18, wherein the movement range of the at least one primary antenna is less than the movement range of the supplementary antenna.

20. A radio base station according to any of claims 1 to 19, wherein the controller is configured to switch the supplementary coverage sector on and off.21 . A method of operating a radio base station comprising the steps of: providing: a plurality of primary sectors each having at least one primary transceiver and defining a primary coverage area; a self-organizing supplementary coverage sector comprising at least one supplementary transceiver and at least one supplementary antenna; varying the supplementary coverage sector by controlling at least one radio coverage parameter of the at least one supplementary antenna.

22. A method according to claim 21 , wherein the at least one radio coverage parameter includes at least one of the following: azimuth orientation of the supplementary antenna; elevation orientation of the supplementary antenna; the radiation pattern of the supplementary antenna; the transmitting power level of the supplementary antenna; and, the receiver sensitivity level of the supplementary antenna.

23. A method according to claim 22, comprising the step of: varying the azimuth heading of the supplementary coverage area by steering the supplementary antenna.

24. A method according to claim 23, comprising the step of: directing the azimuth heading of the supplementary antenna towards an overlapping area of two adjacent primary sectors.

25. A method according to claim 21 , comprising the steps of: providing a plurality of supplementary antennas each defining a different coverage area; and, an RF switch for alternating a connection between each antenna of the plurality, and a network node; varying the supplementary coverage sector by controlling the RF switch to switch the network node connection between the supplementary antennas.

26. A method according to claim 25, wherein the primary RF coverage area defines a plurality of primary RF sectors in different azimuth directions, and wherein the supplementary RF coverage area is positioned between adjacent primary RF sectors.

27. A method according to any of claims 21 to 26, comprising the step of: varying the supplementary coverage sectors based on at least time of day.

28. A method according to any of claims 21 to 27, comprising the step of: varying the supplementary coverage areas based on demand.

29. A method according to any of claims 21 to 28, comprising the step of: varying the supplementary coverage areas based on the presence of a specific RTD or RTS in the coverage area.

30. A method according to any of claims 21 to 29, comprising the step of: moving the at least one primary antenna to vary the primary coverage sector.31 . A method according to any of claims 21 to 30, comprising the step of:turning supplementary sector off when not required.

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