Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W24/00—Supervisory, monitoring or testing arrangements
  • H04W24/02—Arrangements for optimising operational condition
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W24/00—Supervisory, monitoring or testing arrangements

Definitions

• This invention relates to re-configuring a cell-based communication system' s performance according to its operating environment.
• the invention is applicable to, but not limited to, a cell-based communication system that self-configures its cell profile and/or one or more cell operational parameters in response to changes in the cell's operating environment.
• Wireless communication systems typically provide for radio telecommunication links to be arranged between a plurality of base transceiver stations (BTSs) and a plurality of subscriber units, often termed mobile stations (MSs) .
• BTSs base transceiver stations
• MSs mobile stations
• each BTS has associated with it a particular geographical coverage area (or cell) .
• the coverage area is defined by a particular transmitter (and receiver) power level where the BTS can maintain acceptable communications with MSs operating within its serving cell. Often these cells combine to produce an extensive coverage area.
• Wireless communication systems are distinguished over fixed communication systems, such as the public switched telephone network (PSTN), principally in that mobile stations move between coverage areas served by different BTS (and/or different service providers) and, in doing so, encounter varying radio propagation environments.
• PSTN public switched telephone network
• cell-based radio communication systems are categorised as macrocell, microcell or pico cell systems, according to the nominal radius of the cells constituting the system.
• Macrocell systems have cells with radii of over 1km
• microcell systems have cells with radii in the range of 100m to 1km
• picocell systems have cell radii in the range 30m to 100m.
• a number of cell operational characteristics for example, the nominal sizes of the cells and the frequencies upon which the BTSs operate, are determined during the initial setting up and commissioning of the system concerned.
• Cell Profile Such generic classification of a wireless communication system's cell characteristics is termed the "Cell Profile”.
• GSM Global System for Mobile communications
• BTS Node B in a UMTS system
• the Network Operator will therefore configure many cell parameters based upon the Cell Profile.
• a non-exhaustive list for a Global System for Mobile communications (GSM) system would include: (i) Transmit powers for all subscriber and mobile classes, as well as all BTS (or Node B in a UMTS system) carriers in the cell, will be configured based on the cell profile. Cells in urban areas are likely to be set with a lower maximum transmit power than those in rural areas, as the former will be interference limited and the latter coverage limited. In this manner, the 'cell profile' dictates how the system will be configured regarding transmit powers and therefore interference handling mechanisms.
• the expected traffic loading based on the Cell Profile, will determine how many carriers are required in the cell. This, in turn, will dictate the extent of use of congestion relief features such as directed retry, etc.
• the expected paging load will also be based on the Cell Profile, which will dictate how many paging channels are to be made available within the Cell.
• SMS Short Message Service
• SMS Short Message Service
• SDCCH Stand-Alone Dedicated Control Channel
• the respective populations of GSM mobile/subscriber units supporting half-rate and/or adaptive multi-rate (AMR) coder-enabled technologies will determine how aggressive the parameters are set for using alternative speech CODECS . Such parameters are based on the 'cell profile' .
• Handover parameters are also configured based on the Cell Profile. Hence, the selection of a correct cell profile determines how rapid (or slow) handovers are performed.
• the handover characteristic is critical to optimal system performance, for example, to ensure fast handover in a highway environment, whilst slower handovers are perfectly acceptable in a pedestrian environment.
• the inventors of the present invention have recognised a problem with such wireless communication system rollout methodology. Namely, the 'true' communication environment that a cell initially operates in could be different from that predicted. Alternatively, the cell profile could evolve over time, for example, road re- routing resulting in more fast moving subscribers and a higher traffic demand. This would mean that the cell parameter settings, as dictated by the cell profile, are sub-optimal, thereby reducing the quality of service offered by the cell.
• Such a scenario provides the Network Operator at least .
• three major problems first the Network Operator has to detect the reduction in the cell's performance. For this to happen, the Network Operator needs to monitor and track the cell's performance over a short-term and a long-term basis. This is clearly a time consuming and undesirable task.
• the Network Operator has then to ascertain which aspects of the cell's performance are not functioning as anticipated, and why. This is far from an easy task, with so many operational aspects of the communication system being inter-related. Finally, the Network Operator has to re-adjust the cell's parameters to align the parameters with the changing communication environment that the cell is operating in.
• a method of re-configuring a cell operational parameter in a cellular communication system as claimed in Claim 1.
• a storage medium as claimed in Claim 11.
• a mechanism for re-configuring one or more of a cell's operational parameters is described, whereby changes in the environmental conditions of the communication system are detected, for example increased handovers due to a new road layout, by comparing measured environmental data with cell operational characteristics that are dictated by the existing cell profile.
• Appropriate changes . to a cell's operational parameters and/or a cell profile are determined dynamically and implemented automatically, without Network Operator intervention in re-classifying the communication system's cell profile.
• FIG, 1 illustrates a block diagram of a cellular radio communications system adapted to support the various inventive concepts of a preferred embodiment of the present invention
• FIG. 2 illustrates a cell-based communication system adapted to support the various inventive concepts of a preferred embodiment of the present invention
• FIG. 3 illustrates a flowchart of a method of determining whether a cell profile has changed, and adapting the cell operational parameters and/or cell profile in response, in accordance with a preferred embodiment of the present invention.
• the inventive concepts of the present invention alleviate the aforementioned problems associated with the rigid cell-profile classification of a communication cell by utilizing a cell self- configuration mechanism.
• the cell-based communication system detects mis-alignment of cell profile parameters based on measurement data of the prevailing environmental conditions and/or system operations. The system then implements, in a dynamic, manner and autonomous to the Network Operator, the deemed necessary changes to the cell profile and/or cell . operational parameters that are based on the cell profile.
• a cell-based communication system 100 is shown, in outline, supporting a Universal Mobile Telecommunication System (UMTS) air-interface.
• UMTS Universal Mobile Telecommunication System
• GSM Global System for Mobile communication
• ETSI European Telecommunications Standards Institute
• GSM Global System for Mobile communications
• the air-interface protocol is administered from base transceiver sites, termed Node Bs in UMTS nomenclature, within the network architecture 110.
• the Node Bs are geographically spaced apart - one Node B supporting a cell (or, for example, sectors of a cell).
• co-located base transceiver sites supporting, say, both pico- and micro- cellular communications in a GSM or general packet radio system (GPRS) form may also benefit from the inventive concepts described herein.
• a plurality of subscriber units termed user equipment (UE) 112-116 (or user terminals) in UMTS nomenclature, communicate over the selected air-interface 118-120 with a plurality of Node Bs (roughly equivalent to a base transceiver station (BTS) in a GSM or GPRS system) 122- 132.
• BTS base transceiver station
• a limited number of UEs . 112-116 and Node Bs 122-132 are shown for clarity purposes only.
• the Node Bs 122-132 may be connected to a conventional public-switched data network (PDN) 134 (or public-switched telephone network (PSTN)) through radio network controllers (RNCs) 136-140 (roughly equivalent to a base site controller (BSC) in a GSM or GPRS system) .
• the RNCs are operably coupled to external networks, or to other RNCs inside the communication system via a GPRS gateway service node (GGSN) 142-144 (roughly equivalent to a mobile switching centre (MSC) in a GSM or GPRS system) .
• GGSN GPRS gateway service node
• MSC mobile switching centre
• Each Node B 122-132 is principally designed to serve its primary cell, with each Node B 122-132 containing one or more transceiver units and communicating 156-166 with the rest of the cell-based system infrastructure.
• Each RNC 136-140 may control one or more Node Bs 122-132.
• Processes within the GGSNs are provided to account for communication handover, for example in the situation where a UE 112-116 passes between two Node B serving areas.
• Each GGSN 142-144 provides a gateway to the PDN 134, with GGSNs 142-144 interconnected through an operations and management centre (OMC) 146 that administers general control of the cellular telephone communication system 100, as will be understood by those skilled in the art.
• OMC operations and management centre
• the various system elements such as RNCs 136-138 and OMC 146, include control logic 148, 150, 155, with the various system elements usually having an associated memory function 154 (shown only in relation to RNC 138 for the sake of clarity) .
• a memory function 157 of the OMC 146 typically stores the cell profile information for the cells supported by the OMC, historically compiled operational data as well as in-call data, system information such as neighbouring cell-site lists, control algorithms such as a list of frequencies to be scanned by the respective UEs, etc.
• the OMC 146 has been adapted to provide a self-configuring cell profile logic function 155.
• the self-configuring cell profile logic function 155 has been arranged to receive any operational/ environmental data provided by the system elements or UEs relating to the operational characteristics of the respective cells.
• the self-configuring cell profile logic function 155 then preferably applies rule-based logic to the data.
• the rule-based logic determines whether the cell is operating in an anticipated manner, based on its 'cell profile'. If the rule-based logic applied by the self-configuring cell profile logic function 155 determines that the cell characteristics have changed, the self-configuring cell profile logic function 155 re-configures the cell profile or one or more operational parameters of the cell that are affected by the cell profile.
• the memory element 157 has also been adapted to include, for example, a look-up table of the information required to determine and/or implement the changes to the cell operational parameters and/or cell profile.
• the look up table contains information relating to one or more of the following: (i) Cell operational parameters, including ranges of acceptable values for particular cell profile classifications,
• the self-configuring cell profile logic function 155 is also able to re-classify (re-configure) the cell profile autonomously. If the self-configuring cell profile logic function 155 is unable to effect the change, for example, if the change requires a hardware modification, the self- configuring cell profile logic function 155 preferably informs the Network Operator of the changed environmental conditions. The self-configuring cell profile logic function 155 may also inform the Network Operator of the corresponding change required within the system ascertained from, for example, the look-up table in memory element.157,
• one or more Node Bs 122-132 and/or one or more RNCs 136-140 may be adapted to collect the environmental and/or system data. This would then be forwarded to the OMC 146 (or indeed any other associated adjunct) where the cell profiling logic would reside.
• the self-configuring cell profile logic function 155 may be managed within any other element within the infrastructure, such as MSCs 142, 144, or within BSCs 136, 138, 140 or even distributed within a number of elements, if appropriate.
• the self-configuring cell profile logic function 155 could be implemented within the radio access network (RAN) of the cellular infrastructure equipment and/or it may be implemented as a stand-alone element/function on an adjunct platform.
• RAN radio access network
• the dynamic re-configuration of a cell's operational parameters and/or the cell profile may be implemented in a respective communication unit in any suitable manner.
• new apparatus may be added to a conventional communication unit (for example OMC 146) .
• existing parts of a conventional communication unit may be adapted, for example, by reprogramming one or more processors therein.
• the required adaptation may be implemented in the form of processor-implementable . instructions stored on a storage medium, such as a floppy disk, hard disk, PROM, RAM or any combination of these or other storage multimedia.
• FIG. 2 a cell-based communication system, adapted to support the various inventive concepts of a preferred embodiment of the present invention, is illustrated.
• the proposed cell-based communication system continuously measures the cells' operational environment. The measured environmental data is then compared against stored 'cell profile' data. If there is a sufficient difference between the measured cell operational parameters and the stored 'cell profile' data, the system may re-configure, automatically and autonomously from the Network Operator, the cell's operational parameters and/or the cell profile.
• the cell-based communication system 200 preferably includes rule-based logic in the form of an automatic cell profiler 220.
• the automatic cell profiler 220 is preferably located within the OMC 146.
• the automatic cell profiler 220 is operably coupled to a database of cell profiles 215, for example stored within memory element 157 of FIG. 1.
• Environmental (or other) data relating to the cell profile and/or cell operational parameters is obtained from elements within the system. For example, Node B 122 may send 275 environmental data to the OMC 146, so that the OMC 146 can make a determination as to whether the cell profile and/or cell operational parameters match the stored cell profile characteristics.
• the RNC 136 may send 245 environmental data to the OMC 146, so that the OMC can make a determination as to whether the cell profile and/or cell operational parameters match the stored cell profile characteristics.
• one or more RNCs 136 and/or one or more node Bs 122 may include, or be operably coupled to, an agent 235, 265.
• the RNC 136 or Node B 122 preferably configures the agent to seek out and record measurements for the requisite environmental or operational data that may affect the cell profile or cell operational parameters dictated by the cell profile.
• one or more RNCs 136 and/or one or more Node Bs 122 is/are configured to include an automatic cell profiler 240, 270.
• the automatic cell profiler 240, 270 is utilised by the RNC 136 or Node B 122 to re-configure the cell profile and/or one or more cell operational parameters, following the agent obtaining cell environmental or operational information that sufficiently deviates from that expected.
• the database of cell profiles 215 may also include a list of cell operational parameters for respective environmental data values.
• the automatic cell profiler, 240, 270 is able to derive an optimum setting of selected cell operational parameters.
• the relationships may be as sophisticated, or as simple, as required.
• a cell parameter may be adapted if a corresponding measurement value exceeds (or falls below) a threshold.
• complex rule-based criteria may be used.
• the adaptation of a cell parameter may be dependent upon a number of events and/or measurement values.
• a complex rule may require a number of events to happen, or measured data criteria to exhibit a specific performance, before the cell profile and/or one or more cell operational parameters is re-configured.
• the dynamic monitoring and adaptation of one or more cell profile parameters is implemented as a continuous process.
• the process may be initiated by a Network Operator or other external trigger, (such as a periodic timer) .
• the cell's environmental , ,. information may come from any number of sources.
• the information may include:
• Cell statistical information available at the OMC, such as Congestion, Blocking, Mean-Hold Time (MHT), Handover (HO) Cause distribution;
• Control Signalling behaviour This information is readily available to the OMC function in existing systems. It forms the basis of reports generated for the network operator to analyse during the 0 course of his operational activities. This data can also be forwarded to the control logic envisaged by this invention to allow automatic decisions to. be made to adjust aspects for the cell profile.
• MHT Holding Time
• measurements indicate that the cell is experiencing congestion due to more subscribers than anticipated accessing the system. In this case, it would be sensible to enable congestion relief handovers such that some of the cells traffic load is distributed amongst neighbouring cells.
• Another example could be: -
• TA>1, i.e. Timing Advance greater than 1 This indicates that it is providing macrocellular coverage rather than microcellular coverage.
• MICRO*0 any specific microcellular settings
• similar rules are envisaged for CDMA/UMTS based systems whereby cells configured as icrocells ar able to detect signal 5 timings from cells that served subscribers that exceed the anticipated coverage limits of the cell.
• FIG. 3 a flow chart illustrates an ,, overview of the preferred cell re-configuration process.
• the process starts in step 305 and environmental (and/or any other pertinent) data is measured, as shown in step 310.
• the data is checked against any existing cell profile and/or one or more cell operational parameters, as in step 315.
• the measured data 5 shows a significant variation from the existing cell profile and/or one. or more cell operational parameters, for example, by applying a logic-based rule, a determination is made as to whether such a variation causes the existing cell profile and/or one or more cell 0 operational parameters to be re-configured, as shown in step 320.
• step 320 the process continues with further measured 5 data and comparison of the data against the existing cell profile and/or one or more cell operational parameters, in steps 310 to 320.
• step 320 a further determination is made as to whether the system (for example, the OMC) is able to re-configure the cell profile and/or one or more cell operational parameters automatically, in step 325. If the system is able to reconfigure the cell profile and/or one or more cell operational parameters automatically in step 325, the system (for example, the self-configuring cell profile logic function 155 of FIG. 1) does so in step 330 before returning to step 310.
• the system for example, the OMC
• the communication system If the communication system is unable to re-configure the cell profile and/or one or more cell operational parameters automatically in step 325, the system (say, the OMC) informs the Network Operator that a cell profile and/or one or more cell operational parameter change is required, in step 335, and the process returns to step 310.
• the system say, the OMC
• inventive concepts of the present invention utilise dynamic monitoring and adaptation of cell profile information. Such information, when obtained extensively throughout the system, may be determined and assessed to better plan and utilise available communication resources (frequencies) throughout the system. In this manner, it is envisaged that an automatic frequency planning operation may benefit from the inventive concepts described herein.
• the I I OMC 146 may use any additional indicia, such as traffic load, time of day, etc. to enhance the assessment of communications within the communication system. It is also envisaged that the OMC 146 (or other element) may poll Node Bs, MSs, UEs, etc. within the system to obtain such additional indicia.
• UMTS universal mobile telecommunication system
• GSM global system for mobile communications
• CDMA code division multiple access
• TDMA time division multiple access
• iDEN integrated digitally enhanced network
• alternative radio communication architectures • such as private or public mobile radio communication systems could benefit from the inventive concepts described herein.
• a communication system a communication unit, and a method of re-configuring a cell profile and/or one or more cell operational parameters in a cellular communication system have been provided wherein the aforementioned disadvantages associated with prior art arrangements have been substantially alleviated.

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• 2002
  • 2002-10-10 GB GB0223542A patent/GB2394146B/en not_active Expired - Fee Related
• 2003
  • 2003-10-02 AU AU2003282108A patent/AU2003282108A1/en not_active Abandoned
  • 2003-10-02 EP EP03773725A patent/EP1554904A2/de not_active Withdrawn
  • 2003-10-02 WO PCT/EP2003/050677 patent/WO2004034716A2/en not_active Ceased

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