Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
  • H04W4/16—Communication-related supplementary services, e.g. call-transfer or call-hold
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W48/00—Access restriction; Network selection; Access point selection
  • H04W48/02—Access restriction performed under specific conditions
  • H04W48/06—Access restriction performed under specific conditions based on traffic conditions
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
  • H04W16/24—Cell structures
  • H04W16/32—Hierarchical cell structures
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W84/00—Network topologies
  • H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
  • H04W84/04—Large scale networks; Deep hierarchical networks
  • H04W84/042—Public Land Mobile systems, e.g. cellular systems
  • H04W84/045—Public Land Mobile systems, e.g. cellular systems using private Base Stations, e.g. femto Base Stations, home Node B

Definitions

• This invention relates to a method and apparatus for redirecting mobile communication requests made to an access point within a macro cell of a celluar network.
• Mobile communication systems operate on a cellular basis in which transmission and receiver base stations coupled to a network provide transmission and reception to user equipment (UE) such as mobile telephones in each cell in a network.
• UE user equipment
• the base stations themselves are usually referred to as macro base stations and the cells as macro cells.
• Pico cells Smaller cell sites called Pico cells have been proposed. These cover a smaller area such as a complex of buildings. Still smaller cell sites named FEMTO cells are also proposed. This is a term used by mobile operators to refer to cell sites of the type which attempt to solve the often expensive problem of providing complete in building coverage. PICO cells can have problems with low or multi-path distortion etc when they are used to provide coverage to a complete building.
• a FEMTO cell is often referred to as an access point/home gateway. It is a small plug and play device which communicates with user equipment such as mobile handsets using standard 2G or 3G transmission reception. It is connected to the celluar network via a broadband service using either Xdsl (digital subscriber loop) or Wimax Technology.
• a FEMTO cell can incorporate the functionality of a broadband router so that a user has a completely integrated device. It is of course essential that it integrates seamlessly with the core network of the mobile communication system so that it can be remotely managed and updated.
• an access point may have a capacity of ten voice calls which it may handle simultaneously. It is therefore possible that access points can quickly reach their capacity in terms of the calls they can handle and when this happens other users are not able to make calls.
• Preferred embodiments of the present measure provide a method and apparatus to redirect a communication request to a macro cell when an access point has already reached its maximum capacity for calls.
• Preferably embodiments sending a signal back to the piece of UE making the request from the access point advising that perhaps the threshold has been reached, and redirecting the call to a macro cell.
• the message that the capacity threshold has been reached may be an SMS text message.
• a subscriber wishes the call to be redirected to a macro cell he/she again places the call request which is then redirected to on available 2G or 3G Macro cell.
• Figure 1 shows schematically a 3G access point such as a FEMTO cell in communication with a number of pieces of user equipment;
• Figure 2 shows a procedure which takes place when a piece of user equipment tries to make a call by an access point which has already reached capacity
• Figure 3 shows an alternative procedure to that of Figure 2 in a further embodiment of the invention.
• Figure 4 shows the procedure when a user tries to make an emergency call
• FIG. 1 shows an access point 2 which is coupled to a network.
• This comprises an antenna 4 coupled to, or integrated into a controller and a transmit/receive unit.
• this will cover a relatively small area such as a house.
• User equipment such as a mobile phone 6 or a laptop with a data card 8 may be within the house and therefore capable of communication with the access point 2.
• a larger area such as an office environment there may be a number of different pieces of equipment capable of communicating with the access point 2.
• a piece of user equipment When a piece of user equipment initially comes into range of the access point 2, it registers with the access point as being a primary access point on the network for transmission and reception of data. Thus, when the user equipment next tries to communicate such as by making a telephone call, it will attempt to use the access point 2 to access the network.
• the access point is connected to the network typically by a conventional telephone line using a broadband connection (eg ADSL) and as it is meant to be user for residential coverage the total bandwidth (i.e. capacity to serve multiple simultaneous voice/Data cells) it is capable of supporting is considerably less than that of a base station in a macro cell in the network. It is after all designed to take communications from a localised area within a macro cell and will therefore never have been planned to be able to handle the requirements of the whole macro cell. If the access point is a home gateway device its maximum number of communications that it can handle simultaneously may be as little as 4, eg 4 simultaneous voice calls from different mobile telephones all registered with the access point. When the maximum number of possible devices using the access point is reached and another piece of user equipment or subscriber places a request to communicate via the access point, the access point then has to reject the request. This means that the subscriber cannot use the service.
• ADSL broadband connection
• the access point is configured to redirect a piece of user equipment which has its request rejected to use the macro cell within which the access point is positioned.
• this may be undesirable for some subscribers as higher rates may be payable in comparison to using an access point. Therefore, in a preferred embodiment of the invention, instead of redirecting and rejecting a request automatically, the system is configured to notify the subscriber that his request has been rejected such that he may chose to disallow the opportunity to have his request redirected to the macro cell.
• FIG. 2 A flow diagram showing communications between a piece of user equipment 20 and an access point 22 is shown in figure 2. The description of this assumes that the user equipment 20 is already registered with the access point 22 and will attempt to use this for its communications.
• the user equipment When the user equipment wishes to make a communication such as a voice call via the access point 22 it first sends a radio resource control (RRC) connection request to the access point 22.
• RRC radio resource control
• the access point 22 and the user equipment 20 then perform an RRC connection set up which will initially establish this contact between the user equipment 20 and the access point 22.
• a determination is then made at 24 as to whether or not the access point has reached maximum capacity. If it has not, then the normal call set up procedure between the user equipment 20 and access point 22 is performed at 26. This does not form the subject matter of the present invention and is therefore not described here. It will be well known to those skilled in the art.
• the access point 22 has started a timed period during which it will in response to an RRC connection request from that piece of the attempt to match the user identity of the user making the RRC connection request with the user identity stored at 26. This is done at 32. If the user identity is matched, the RRC connection request is rejected and "redirection information" (which contains the GSM Cell information and UMTS frequency Information) is sent back to the user equipment. In response to this, the software running in user equipment redirects the call into the appropriate macro cell using, for example, the GSM or UMTS frequency band as specified in "Redirection information".
• the user equipment is configured to respond to an RRC connection request which includes "redirection information" to transmit the call into the appropriate macro cell.
• This functionality can be implemented in software in a piece of user equipment by those skilled in the art.
• FIG 3 A flow diagram showing the events which take place in a system using 3GPP Release ⁇ and above compliant handsets is shown in figure 3.
• the first part of the procedure between the user equipment and access point 22 is the same as that described in relation to figure 2 as far as the determination as to whether or not the maximum capacity of the access point has been reached at 24. If maximum capacity has not been reached, then the normal call set up procedure is entered at 26. If it has been reached, then the access point sends an SMS message at 28 to the user equipment 20 to notify it of the connection rejection or sends a voice message at 29.
• the access point 22 then commences a RRC connection release procedure with the user equipment 20 which causes the user equipment 20 to automatically register with the relevant macro cell, the information for which may be provided in the "redirection information".
• the user can then make his call via the macro cell. It is assumed in Figure 3 and Figure 4 that macro cell coverage (either GSM or UMTS) is available. If it is not then obviously the redirection procedure cannot be initiated by Access Point. As in the previous embodiment, the system can be configured such that no SMS message is sent by the access point to the user equipment whereby the user equipment will automatically try to use the macro cell if the connection request is rejected.
• macro cell coverage either GSM or UMTS
• Figure 4 shows a modification of the system which can be used with the systems of either Figure 2 of Figure 3.
• the user equipment tries to make an emergency call by using a recognised emergency number (eg 999 in the United Kingdom) the user equipment instantly sets up an RRC connection request to the access point 22.
• a determination is made at 40 as to whether or not the connection request is for an emergency call or not by checking the "cause value" specified in RRC CONNECTION REQUEST message. If it is not, then it can enter normal set up procedure at 42. This will entail going through the process of Figure 2 or Figure 3 to determine whether or not the access point has reached its maximum capacity. If the call is an emergency call, a determination is made at 44 as to whether or not macro cell coverage is available.
• the normal call set up procedure is entered at 26. This is equivalent to the normal call set up procedure of Figure 2 and 3. If macro cell coverage is available, it is preferable for the call to be routed via the macro cell and therefore an RRC connection rejection is sent back to the user equipment 20 with redirection information for the relevant macro cell. The user equipment is configured to respond automatically to this to redirect the call to the macro cell, thereby ensuring that the emergency call is made.
• an access point must be arranged to check whether or not its maximum capacity limit has been reached and thus be capable of notifying user equipment about the status of maximum capacity and the possibility of redirection to a macro cell. The access point must be able to determine if macro cell coverage is available.
• User equipment must be configured to be able to redirect the calls to the macro cell, either using data already stored in the user equipment or data provided by the access point when a RRC connection request is rejected.
• emergency call handling the access point must be able to determine whether or not an emergency call has been made and be able to redirect the emergency call to the macro cell if macro cell coverage is available. All these function can be implemented in software in the user equipment and the access point in a manner that will be well known to those skilled in the art.

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

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Publications (1)

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• 2007
  • 2007-05-30 GB GB0710329A patent/GB2449672B/en not_active Expired - Fee Related
• 2008
  • 2008-05-28 WO PCT/JP2008/060237 patent/WO2008149867A1/en not_active Ceased
  • 2008-05-28 JP JP2009550187A patent/JP5246168B2/ja not_active Expired - Fee Related
  • 2008-05-28 CN CN2008800173018A patent/CN101682834B/zh not_active Expired - Fee Related
  • 2008-05-28 EP EP08765050.3A patent/EP2151140B1/en not_active Not-in-force
  • 2008-05-28 US US12/451,661 patent/US8649782B2/en active Active

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