Abstract:
Wireless links used as backhauls for wireless access networks may be provided by an HSDPA, while hot spots for network access may be built using another radio technology, such as WLAN. There may be several end-user terminals simultaneously accessing the network through the hot spot. Information on the number of user terminals connected to a hot spot is found out, and the information is provided to a backhaul network. The backhaul network then allocates the backhaul network resources between the user terminals connected to the hot spot and the user terminals connected to the backhaul network such that the number of user terminals connected to the hot spot is taken into account.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a method of allocating backhaul network resources to user terminals by utilizing access points of another network, such as a WLAN (Wireless Local Area Network). 
       BACKGROUND OF THE INVENTION 
       [0002]    Wireless links are used as backhauls for wireless access networks e.g. in rural areas where it is expensive to build wired links. A backhaul link may be provided by means of a radio access network using a selected radio network technology, such as HSDPA (High-speed Downlink Packet Access), WiMAX (Worldwide Interoperability for Microwave Access) or flash-OFDM, while hot spots for network access may be built using another radio technology, such as WLAN. In wireless LAN technology, user terminals are provided with wireless LAN connections in order to access, for instance, the Internet through wireless LAN access points which are mainly located in “hot spots”. The backhaul network technologies usually allocate their radio resources to end-users in time division and round robin manner. 
         [0003]    A problem associated with the above arrangement is that when allocating resources, the network providing the backhaul link logically treats the access point located in the hot spot network as one end-user. This means that if several end-users are simultaneously accessing the network through the hot spot, they have to share an amount of resources that corresponds to an amount of resources the backhaul network would provide to a single end-user. At the same time, an end-user directly accessing the backhaul network receives an amount of resources equal to that received by the hot spot end-users altogether. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0004]    An object of the present invention is thus to provide a method, a communications system and an access point for implementing the method so as to alleviate the above problem. The objects of the invention are achieved by a method and an arrangement which are characterized by what is stated in the independent claims. Embodiments of the invention are disclosed in the dependent claims. 
         [0005]    The invention is based on the idea that information on the number of user terminals connected to a hot spot is found out, and the information is provided to a backhaul network. The backhaul network then allocates the backhaul network resources between the user terminals connected to the hot spot and the user terminals connected directly to the backhaul network such that the number of user terminals connected to the hot spot is taken into account. 
         [0006]    An advantage of the method and arrangement of the invention is that the network resources can be divided evenly and/or according to operator needs between users directly connected to the backhaul network and users connected to the backhaul network via another wireless network. Thus the allocation of the network resources can be controlled by the operator both in the access network providing the hot spots as well as in the access network providing the backhaul. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    In the following, the invention will be described in greater detail by means of embodiments with reference to the accompanying drawings, in which 
           [0008]      FIG. 1  illustrates a communications system according to the present invention; 
           [0009]      FIG. 2  is a signalling chart illustrating a method according to the present invention; 
           [0010]      FIG. 3  is a flow chart illustrating how an access point of a wireless access network according to the present invention functions; 
           [0011]      FIG. 4  is a flow chart illustrating how an access point of a backhaul network according to the present invention functions; 
           [0012]      FIG. 5  illustrates prioritisation according to an embodiment of the present invention; 
           [0013]      FIG. 6  illustrates a mesh network according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0014]    In the following, preferred embodiments of the invention will be described with reference to a wireless communications system, such as UMTS (Universal Mobile Telecommunications System), WCDMA (Wideband Code Division Multiple Access), HSDPA, WiMAX, OFDM or WLAN. This invention is not, however, meant to be restricted to these embodiments. Consequently, the invention may be applied to any wireless or mobile communications system capable of providing a packet switched radio service. Especially the specifications of 3rd generation (3G) mobile communications systems advance rapidly. This may require additional changes to the invention. For this reason, the terminology and the expressions used should be interpreted in their broadest sense since they are meant to illustrate the invention and not to restrict it. The relevant inventive aspect is the functionality concerned, not the network element or equipment where it is executed. 
         [0015]    HSDPA is a feature of the WCDMA, providing high data rate trans-mission on the downlink to support multimedia services. HSDPA provides 3G terminals with high-speed data delivery, ensuring that users requiring effective multimedia capabilities benefit from data rates previously unavailable because of limitations in the radio access network RAN. 
         [0016]    WiMAX has been defined by the WiMAX Forum to promote conformance and interoperability of the WLAN standard. The WiMAX refers to a wireless technology that provides high-throughput broadband connections over long distances. It can be used for a number of applications, including “last mile” broadband connections, hotspots and cellular backhaul, and high-speed enterprise connectivity for business. The WiMAX provides increased bandwidth and stronger encryption. It makes use of multi-path signals, and enables connectivity to be provided between network endpoints without direct line of sight. The use of WiMAX for “last mile” connectivity may result in better price-points in both business and home applications, and WiMAX enables broadband access in areas with no existing physical cable or telephone networks. 
         [0017]    OFDM is an FDM (Frequency Division Multiplexing) modulation technique for transmitting large amounts of digital data over a radio wave. OFDM operates by splitting a radio signal into multiple smaller sub-signals that are then transmitted simultaneously to the receiver at different frequencies. OFDM enables the amount of disturbance to be reduced in signal transmissions. 
         [0018]    Flash-OFDM is a signal processing scheme that supports high data rates at very low packet and delay losses, also known as latencies, over a distributed all-IP wireless network. Such low-latency enables real-time mobile interactive and multimedia applications. It delivers a higher quality wireless service and improves the cost effectiveness of the wireless data technologies. 
         [0019]      FIG. 1  illustrates a communications system S according to an embodiment of the present solution.  FIG. 1  shows a simplified version of the network architecture, only illustrating components that are essential to the invention, even though those skilled in the art naturally know that a general wireless or mobile communications system also comprises other functions and structures, which do not have to be described in more detail herein. In  FIG. 1 , the telecommunications system S comprises two access networks AN 1  and AN 2 . A first access network AN 1  is, for example, a WLAN network, and it comprises a first access point AP 1  with which user terminals UE-X and UE-Y within the coverage area of AP 1  may communicate. A second access network AN 2  comprises a second access point AP 2  with which a user terminal UE 2  within the coverage area of AP 2  may communicate. The radio link between AP 1  and UE-X, as well as a radio link between AP 1  and UE-Y, is implemented by utilizing a first radio technology, such as WLAN. A radio link between AP 1  and AP 2 , as well as a radio link between AP 2  and UE 2 , is implemented as a backhaul link by utilizing a second radio technology, such as HSDPA, WiMAX or flash-OFDM. The second access point AP 2  may be connected to a core network CN 2  by utilizing a wired link, such as an optical fiber or a copper cable link. From the point of view of AP 2 , AP 1  represents a user terminal UE 1  capable of communicating with AP 2  by utilizing the backhaul link between AP 1  and AP 2 . The access points AP 1 , AP 2  may also be referred to as base stations. It should be noted that in addition to AN 1 , also other access networks may or may not be served by the backhaul network AN 2 . 
         [0020]    Thus, a first radio access network AN 1  is provided, implemented with a first radio technology (e.g. WLAN), and a second radio access network AN 2 , implemented with a second radio technology (e.g. HSDPA). The second access network AN 2  is used for end-user network access, as well as a backhaul link for the hot spot network, by means of the second radio technology. In a way, the hot spot base station AP 1  resembles a user terminal UE 1  connected to the second access network AN 2 . 
         [0021]    In previous solutions, when considering a case where several users UE-X, UE-Y reside in the hot spot AP 1 , and one user terminal UE 2  directly in the backhaul-providing network AN 2 , the resources of AP 2  would not be evenly divided between the end-users UE-X, UE-Y, UE 2 . The two users UE-X, UE-Y in the hot spot AP 1  would have to share an amount of resources similar to that received by the single user terminal UE 2  in the second network AN 2  alone. 
         [0022]    In the present solution, a new functionality is added to the base station AP 1  of the hot spot and to the base station AP 2  of the backhaul network, which enables the resources to be divided evenly (or, if desired, according to operator needs). The hot spot base station AP 1  is aware of the number of end-users UE-X, UE-Y currently residing within the hot spot AP 1 . The present solution is based on the idea that information on the number of user terminals UE-X, UE-Y currently connected to the hot spot AP 1  is transmitted from the hot spot base station AP 1  to an RRM (Radio Resource Management, not shown in the figures) functionality of the backhaul-providing network AN 2 . The RRM functionality may reside e.g. in the base station AP 2  and/or in a radio network controller (not shown) of the backhaul network AN 2 . The RRM is then arranged to adopt the resource scheduling according to the number of end-users UE-X, UE-Y in the hot spot AP 1  and, if desired, according to the number of end-users UE 2  connecting directly through the backhaul network AN 2 . 
         [0023]    The backhaul network resources may be allocated either on the basis of the number of user terminals UE-X, UE-X connected to AP 1  only, or on the basis of the number of user terminals UE-X, UE-X connected to AP 1  and the number of user terminals UE 2  connected to AP 2 . 
         [0024]    According to an embodiment, even scheduling is applied. In such a case, all the end-users UE-X, UE-Y, UE 2  receive an equal amount of resources, i.e. the RRM calculates the total number of end-users in AN 1  and AN 2  cells and divides the total amount of resources evenly. Thus, in the situation shown in  FIG. 1 , the “logical” user terminal UE 1  in the hotspot AP 1  receives more resources than UE 2 , as the number of current users in AN 1  is higher than the number of current users in AN 2  (i.e. 2&gt;1). 
         [0025]    According to another embodiment, the hotspot AP 1  is prioritised. In such a case, the RRM is arranged to provide more resources to the “logical” user terminal UE 1  in the hotspot AP 1 . There may be a specific (e.g. operator-specific) reason for this, or the hotspot AP 1  usage may be encouraged due to a better coverage and/or less interference that may be achieved. 
         [0026]    According to yet another embodiment, direct users UE 2  in the second network AN 2  are prioritised. A reason to prioritise the user terminal UE 2  directly connected through the backhaul network AN 2  may be because the hotspot AP 1  may be a secondary customer to the backhaul operator, or because the pricing may be different in direct AP 2  access. 
         [0027]    The present solution thus provides a resources allocation scheme that enables the resources to be evenly divided between the end-users UE-X, UE-Y in the hot spot AP 1  and the end-users UE 2  directly accessing the backhaul network AN 2 . If no even division is desired, the present solution also enables the resources to be divided, for example, according to the needs of the network operator. 
         [0028]      FIG. 2  illustrates signalling according to an embodiment of the present solution. At first, a user terminal UE-X connects  2 - 1  to a first access point AP 1  (or alternatively disconnects from the AP 1 ). Thus the number of user terminals served by AP 1  changes, and this change is acknowledged in step  2 - 2  by the first access point AP 1 . Step  2 - 2  is carried out either by periodically requesting the number of users or on the basis of event-based reporting in the AP 1 . The event-based reporting refers to the AP 1  recognizing if a user terminal starts or ends a session with AP 1 . Thus the first access point is able to update  2 - 2  the user count. Next, a change in the resources is requested by transmitting an update resources request message  2 - 3  from UE 1  to an RRM functionality (which may be located in a second access point AP 2  or some other network element in AN 2 ). The message  2 - 3  may include information on the number of user terminals recently connected/disconnected to/from AP 1 , and/or information on the total number of user terminals in AP 1 . In step  2 - 4 , an RRM algorithm calculates a new scheduling policy for user terminals/access points served by AP 2 , and AP 2  starts to allocate the modified radio resources to UE 1 /AP 1  and UE 2 . In a message  2 - 5 , a response is transmitted to UE 1 /AP 1 , indicating that the requested resource update action has been carried out (or rejected if for some reason prohibited). In step  2 - 6 , the response is received by AP 1 /UE 1 . The updated resources can now be utilized by the user terminals UE-X, UE-Y, UE 2  (unless the update request was rejected). 
         [0029]      FIG. 3  illustrates the operation of a first access point AP 1  located in a first access network AN 1 . In step  3 - 1 , an opening/termination of a session between the access point AP 1  and a user terminal UE-X, UE-Y is registered. Step  3 - 1  is carried out either by periodically requesting the number of users terminals or on the basis of event-based reporting. Thus a user count can be updated in step  3 - 2 . Next, a change in resources is requested by transmitting  3 - 3  an update resources request message to the RRM functionality located in a second access point AP 2  (or some other network element in AN 2 ). The message may include information on the number of user terminals recently connected/disconnected to/from AP 1 , and/or information on the total number of user terminals in AP 1 . In step  3 - 4 , a response is received in UE 1 /AP 1 , indicating that the requested resource update action has been carried out (or rejected if for some reason prohibited). 
         [0030]      FIG. 4  illustrates the operation of a second access point AP 2  located in a second access network AN 2 . In step  4 - 1 , a resource update request message is received from AP 1  UE 1 . The message may include information on the number of user terminals UE-X, UE-Y recently connected to/disconnected to/from AP 1 , and/or information on the total number of user terminals in AP 1 . In step  4 - 2 , an RRM functionality (which may be located in the second access point AP 2  or some other network element in AN 2 ) calculates a new scheduling policy for user terminals/access points served by AP 2 , and AP 2  starts to schedule the modified radio resources for UE 1 /AP 1  and UE 2 . In step  4 - 3 , a response is transmitted to UE 1 /AP 1 , indicating that the requested resource update action has been carried out (or rejected if for some reason prohibited). 
         [0031]      FIG. 5  illustrates, by way of example, a prioritisation scheme according to the present invention, by means of which AP 2  is able to allocate resources in the network when prioritisation is applied. In step  5 - 11  of  FIG. 5 , the number of user terminals served by AP 1 /UE 1  is defined as “N 1 ” (based on the information received from AP 1  as described above). The number of user terminals served by other access points in the network is defined in step  5 - 2  as “B”. The total number “C” of served user terminals in the network can thus be calculated in step  5 - 3  as follows: C=N 1 +B. The amount “R 1 ” of resources allocated to the user terminal AP 1 /UE 1  is calculated in step  64  as follows: R 1 =k N1 −N 1 /C, and the amount “R 2 ” of resources allocated to the user terminal AP 1 /UE 1  can be calculated in step  5 - 5  as follows: R 2 =k N2 ·N 2 /C, wherein k N1  and k N2  represent weighting factors by means of which an operator is able to prioritise a respective selected access point AP 1 , AP 2 . Thus, by selecting a high value of the corresponding weighting factor, the operator is able to allocate more resources to the access point than suggested by the number of user terminals served by the access point. 
         [0032]    According to yet another embodiment, the present invention is applied to a mesh network where user terminals may also function as access points for other terminals. This embodiment enables the mesh network to be scheduled with a unified and fair mechanism. The embodiment is illustrated by way of a simplified example in  FIG. 6  in which the functionality according to the embodiment is implemented in access points (i.e. in user terminals) UE-M 1 , UE-M 2 , UE-M 3 , UE-M 4 , UE-M 5 , UE-M 6 , UE-M 7 . The access point UE-M 1 , UE-M 2 , UE-M 3  is arranged to report the number of respective active user terminals UE-M 2 , UE-M 3 , UE-M 4 , UE-M 5 , UE-M 6  “below” it in the mesh network hierarchy to an access point BS, UE-M 1 , UE-M 2 , UE-M 3  which is serving it. The base station BS represents an access point of the backhaul network. The number of active user terminals below the access point is determined on the basis of reports received from the terminals below. The number of user terminals is the actual number of active users in the whole network branch below the access point (+1, if the access point UE-M 1 , UE-M 2 , UE-M 3  itself is active), not the number of terminals only directly below the access point. In a situation where user terminal is served by more than one access point, the reports can be divided between the respective access points such that resource fairness is restored. In the situation of  FIG. 6 , the user terminal UE-M 4  is served by access points UE-M 2 , UE-M 3 . In such a case, no further user terminals exist in the hierarchy below UE-M 4 , but UE-M 4  itself is active, so it should report to the access point serving it that the number of access points is 1. As there are two access points UE-M 2 , UE-M 3  serving UE-M 4 , the value “1” is to be divided by two, i.e. ½=0.5. The numbers to be reported by the user terminals to the corresponding access points directly above them are shown in  FIG. 6 . 
         [0033]    It should be noted that the RRM functionality and/or the functionality according to the present invention may be located in the hot spot access point and/or in the backhaul access point. On the other hand, the RRM functionality and/or the functionality according to the present invention may be located in a separate network element not shown in the figures (such as in a radio network controller or in an authentication centre, or even in a core network element). 
         [0034]    It should be noted that the access point AP 1 /UE 1  is able to obtain information on the number of user terminals UE-X, UE-Y connected to it. The access point AP 2  of the backhaul network is able to obtain information on the number of user terminals UE 2  connected to AP 2 . 
         [0035]    It should also be noted that herein the term “connect” may also refer to a logical connection (a session) between the user terminal and the access point, although it is obvious to a person skilled in the art that the WLAN and HSDPA are based on a packet-switched data transmission utilizing connectionless protocols. 
         [0036]    The items and steps shown in  FIGS. 2 ,  3  and  4  are simplified, and only aim at describing the idea of the invention. Other items may be used and/or other functions may be carried out between the steps. The items only serve as examples and they may only contain some of the information mentioned above. The items may also include other information, and the titles may deviate from those given above. Instead of or in addition to an access point or a base station, the above described operations may be performed in any other element of a communications system. 
         [0037]    In addition to prior art means, a system, networks or network nodes that implement the functionality of the invention comprise means for processing information relating to resource allocation in a manner described above. Existing network nodes and user terminals comprise processors and memory that can be utilized in the operations of the invention. Any changes necessary for implementing the invention may be carried out using supplements or updates of software routines and/or routines included in application specific integrated circuits (ASIC) and/or programmable circuits, such as EPLDs (Electrically Programmable Logic Device) or FPGAs (Field Programmable Gate Array). 
         [0038]    It will be obvious to a person skilled in the art that as technology advances, the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.