(19)
(11)EP 2 989 832 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
14.08.2019 Bulletin 2019/33

(21)Application number: 14724801.7

(22)Date of filing:  24.04.2014
(51)Int. Cl.: 
H04W 48/18  (2009.01)
H04W 36/16  (2009.01)
H04W 48/20  (2009.01)
H04W 84/12  (2009.01)
(86)International application number:
PCT/IB2014/060989
(87)International publication number:
WO 2014/174484 (30.10.2014 Gazette  2014/44)

(54)

CONDITIONAL OFFLOADING FROM WLAN TO CELLULAR NETWORK

BEDINGTES OFFLOADING VON WLAN ZU ZELLULAREN NETZWERK

OFFLOADING CONDITIONEL D'UN RÉSEAU WLAN VERS UN RÉSEAU CELLULAIRE


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 26.04.2013 US 201361816301 P
30.09.2013 US 201314042493

(43)Date of publication of application:
02.03.2016 Bulletin 2016/09

(73)Proprietor: Telefonaktiebolaget LM Ericsson (publ)
164 83 Stockholm (SE)

(72)Inventors:
  • HUANG, Kaiyuan
    Kanata, Ontario K2K 2P2 (CA)
  • TAM, Gary
    Taikoo Shing, Hong Kong (CN)
  • RAYMENT, Stephen
    Ottawa, Ontario K1R 1E2 (CA)

(74)Representative: Zacco Sweden AB 
Valhallavägen 117 Box 5581
114 85 Stockholm
114 85 Stockholm (SE)


(56)References cited: : 
WO-A2-2011/028258
US-A1- 2012 320 888
US-A1- 2013 084 864
WO-A2-2012/022965
US-A1- 2013 077 599
  
  • AT&T ET AL: "WLAN-NS Key Issue #4 - Solution", 3GPP DRAFT; S2-131426_S2_96_WLAN NS LOAD INFOR_REVISED3, 3RD GENERATION PARTNERSHIP PROJECT (3GPP), MOBILE COMPETENCE CENTRE ; 650, ROUTE DES LUCIOLES ; F-06921 SOPHIA-ANTIPOLIS CEDEX ; FRANCE , vol. SA WG2, no. San Diego, California, USA; 20130408 - 20130412 13 April 2013 (2013-04-13), XP050708640, Retrieved from the Internet: URL:http://www.3gpp.org/ftp/tsg_sa/WG2_Arc h/TSGS2_96_San_Diego/Docs/ [retrieved on 2013-04-13]
  
Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


Description

TECHNICAL FIELD



[0001] The disclosure relates generally to wireless communications and, more particularly, to controlling selection by a user terminal between two access networks, such as a cellular network and wireless local area network.

BACKGROUND



[0002] Wireless user terminals, such as smartphones, tablets, and laptop computers, are designed to favor a Wireless Fidelity (Wi-Fi) connection as opposed to a cellular network connection. Whenever a user terminal is able to connect to a Wi-Fi cell in a Wireless Local Area Network (WLAN), it will automatically switch its network connection for Internet services to the WLAN from the cellular network such as a Third Generation Partnership Project (3GPP) network. This approach helps offload data traffic from the cellular network and is used by most cellular phones on the market.

[0003] This network selection bias favoring WLAN does not always provide the user with the best possible service. It does not take into consideration the network conditions for the two types of access networks (WLAN and cellular). Even when the Wi-Fi cell is very congested and the cellular network is lightly loaded, the user terminal will still select the Wi-Fi cell. Similarly, when a user terminal is further away from a Wi-Fi cell with marginal signal quality and the quality of service with Wi-Fi is poor, the user terminal will still connect through the Wi-Fi cell even though the cellular network can provide better service (e.g., higher data throughput).

[0004] From US 2013/0084864 A1, systems and techniques for handover management in wireless communication networks are known. In this regard, an apparatus, such as a base station, receives information relating to load conditions and computes handover threshold information based on the information relating to the load conditions. The information relating to the load conditions comprise information received from other base stations, and the base station in turn shares its own information. Information are shared through direct communication between base stations, or are managed by a controller. Handover thresholds are set for user devices based on the load metric information.

[0005] In WO 2011/028258 A1, techniques in systems for wireless communications are described that provide handover functions between two different wireless radio access networks, and idle and paging mechanisms involving two different wireless radio access networks. A wireless communication system includes a first radio access service network based on hierarchical cells and a second private radio access network to collectively provide wireless communication services to mobile stations within the system. A macrocells of the first radio access service network uses information on the mobile stations' permission to access the private radio access service network to instruct the mobile station being served by the macrocell in the first radio access service network to take and report measurements on private cells of the second private radio access network. Based on the measurement reports, the macrocell determines when to instruct the mobile station to perform a handover to a permitted private cell based on a handover policy.

[0006] Document WO 2012/022965 A1 may be construed to disclose methods and an apparatus for controlling access of a mobile device to a femtocell base station in a communications network. The method determines whether to allow access of the mobile device to the femtocell base station based on the femtocell-mobile device path loss for transmissions between the mobile device and the femto- cell base station. Access may be allowed if the femtocell-mobile device pathloss is lower than a threshold amount. Additionally or alternatively access may be allowed only if the femtocell-mobile device pathloss is lower than the macrocell-mobile device pathloss for transmissions between the mobile device and a macrocell base station. The method is particularly applicable for hybrid access mode femtocells and additional conditions may be applied regarding the number of mobile device that are not part of the subscriber group that can access the femtocell. The method may be implemented by the femtocell, the macrocell or by any other suitable network device.

[0007] Document "WLAN-NS Key Issue #4 - Solution", SA WG2 Temporary document S2-131426, AT&T et.al. may be construed to disclose a technique pertaining to HS2.0 that allows the mobile device connectivity manager to gather information related to the BSS load and ANQP-WAN metrics information, which together with information on signal strength measurements and interference can be used to estimate whether a mobile device will get an adequate QoS on the target WLAN AP. Additionally, HS2.0 has recently introduced the policy for the minimum threshold of available backhaul (WAN) bandwidth at a hotspot network which permits to estimate the expected QoS on a target WLAN AP before switching the device to it. This will enhance the user experience significantly, especially in a scenario where WLAN is widely deployed and used.

[0008] Further prior art is known from US 2012/0320888 A1.

SUMMARY



[0009] According to the disclosure, there are provided a method and an apparatus according to the independent claims. Developments are set forth in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS



[0010] 

Figure 1 illustrates a communication network implementing the traffic steering approach as described herein.

Figures 2A and 2B illustrate switching by a user terminal between a cellular network cell and Wi-Fi cell.

Figure 3 illustrates the WiFi/3GPP access selection approach based on use of an admission threshold to control the effective size of a Wi-Fi cell.

Figure 4 illustrates an exemplary method of correlating cellular network cells with Wi-Fi cells.

Figure 5 illustrates a correlation method implemented by a network node in the WLAN.

Figure 6 illustrates an exemplary method of steering traffic between cellular network cells and Wi-Fi cells.

Figure 7 illustrates a WiFi/3GPP access selection method implemented in a WLAN.

Figure 8 illustrates exemplary processing performed by an access control node in a WLAN.

Figures 9A and 9B graphically illustrate a method of computing a weighted average user terminal throughput used for traffic steering.

Figure 10 illustrates a method of predicting a current user terminal throughput from historical data.

Figure 11 illustrates an exemplary method of predicting a current value of a performance measurement.

Figure 12 illustrate an exemplary network node.


DETAILED DESCRIPTION



[0011] The present disclosure describes techniques for steering traffic between two different access networks. The techniques described herein are generally applicable to any type of wireless communication network. As an aid in understanding the disclosure, exemplary embodiments of the steering techniques will be described in the context of WiFi/3GPP access selection between a cellular network and a wireless network based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards.

[0012] Figure 1 illustrates an exemplary communication environment comprising first and second access networks in which the access selection techniques may be employed. The first access network comprises a Wireless Local Area Network (WLAN) 50 operating according to the IEEE 802.11 family of standards. The WLAN 50 includes one or more access points (APs) 55 that provide coverage in respective Wi-Fi cells 60. A single AP 55 may serve multiple Wi-Fi cells 60. The second access network comprises a cellular network 10, such as a Global System for Mobile Communication (GSM) network, Wideband Code Division Multiple Access (WCDMA) network, Long Term Evolution (LTE) network, or other cellular network. The cellular network 10 includes a packet core network 15 and radio access network (RAN) 20. The RAN 20 includes one or more base stations (BSs) 25 that provide coverage in respective cells 30 of the cellular network 10. A single base station 25 may serve multiple cellular network cells 30.The packet core network 15 provides connection to external networks, such as the Internet 40 and IP Multimedia Subsystem (IMS) networks 45.

[0013] A dual mode user terminal 100 is also shown that is capable of communicating with both the base stations 25 in the cellular network 10 and the APs 55 in the WLAN 50. The user terminal 100 is identified in the cellular network 10 by an International Subscriber Identity (IMSI). The user terminal 100 is identified in the WLAN 50 by a Medium Access Control (MAC) address.

[0014] The WLAN 50 includes an Access Control (AC) node 70 with an Access Network Supervisor (ANS) function that controls admission to the WLAN 50. The AC node 70 communicates with an Operation and Support System (OSS) 35 in the cellular network 10 as will be hereinafter described in more detail. Although shown separately, the OSS 35 may be located in the core network 15 of the cellular network 10. In one exemplary embodiment, the AC node 70 sends requests for information to the OSS 35. For example, the AC node 70 may request a cell ID or performance measurements for a cellular network cell 30 or a group of cells. In response to the request for information, the OSS 35 may send the requested information to the AC node 70.

[0015] Figure 2A illustrates the current traffic steering approach in use today where a user terminal 100 favors a WLAN connection over a cellular network connection. A user terminal 100 having a cellular network connection will switch to a Wi-Fi cell 60 as soon as it is able to connect to the Wi-Fi 60 cell even though the cellular network 10 provides higher throughput than the WLAN 50. There is no coordination between the cellular network 10 and the WLAN 50. The immediate switching to the Wi-Fi cell 60 by the user terminal 100 as soon as it is able to establish a connection with the Wi-Fi cell 60 results in a significant drop in data throughput for the user terminal 100. This approach becomes more problematic with the increasing number of Wi-Fi cells 60.

[0016] Figure 2B illustrates an alternative approach according to one embodiment of the disclosure. As shown in Figure 2B, the user terminal 100 does not immediately switch to the Wi-Fi cell 60 as soon as it is able to establish a connection to the Wi-Fi cell 60. Rather, switching from the cellular network 10 to the Wi-Fi cell 60 is based on expected performance of the Wi-Fi Cell 60 relative to the cellular network cell 30. In one embodiment, switching from the cellular network 10 to the Wi-Fi cell 60 is delayed until the data throughput for the Wi-Fi cell 60 is roughly equal to the data throughput for cellular network 10. This approach provides a better experience for the user.

[0017] The traffic steering in one embodiment has two major components. First, the cellular network cells 30 providing overlapping coverage with a Wi-Fi cell 60 are identified and correlated with the Wi-Fi cell 60. Second, adaptive steering control is provided by adjusting a Received Signal Strength Indicator (RSSI) threshold used for admitting user terminals 100 to the Wi-Fi cell 60. The threshold is referred to herein as the RSSI-Admit threshold or admission threshold.

[0018] The cellular network cells 30 may, for example, comprise GSM cells, WCDMA cells, LTE cells, or a combination thereof. In one embodiment, up to nine cellular network cells 30 can be correlated with a single Wi-Fi cell 60. Any additional cellular network cells 30 of lesser significance are ignored. The correlation of cellular network cells 30 to Wi-Fi cells 60 is performed automatically on an ongoing basis so that changes in network configuration are detected and accounted for. Changes in network configuration may, for example, be due to cell splitting, addition of cells, deletion of cells, etc.

[0019] The RSSI-Admit threshold is used to control the effective coverage area or effective size of a Wi-Fi cell 60. A user terminal 100 is admitted when the RSSI-Admit threshold is met and is not admitted otherwise. Lowering the RSSI-Admit threshold increases the effective coverage area of the Wi-Fi cell 60. Raising the RSSI-Admit threshold decreases the effective coverage area of the Wi-Fi cell 60.

[0020] The adjustment of the RSSI-Admit threshold may be performed for all Wi-Fi cells 60 in the WLAN 50 by a centralized access control (AC) node 70 in the WLAN 50. Alternatively, each AP 55 in the WLAN 50 network may separately determine the RSSI-Admit threshold for Wi-Fi cells 60 served by the AP 55.

[0021] Predicted average throughput for the Wi-Fi cell 60 is used to set the RSSI-Admit threshold and thus control the effective cell size. In one exemplary embodiment, the RSSI-Admit threshold is set so that the predicted average throughput for the Wi-Fi cell 60 is roughly equal to the cellular network cell 30. In some embodiments, a carrier configurable bias may be used to allow a carrier to favor either the cellular network 10 connection or the WLAN 50. The bias can be dynamically adjusted depending on current conditions. For example, when the cellular network 10 is congested, the carrier may favor the WLAN 50over the cellular network 10 to reduce the load on the cellular network 10. When the load in the cellular network 10 is light, the carrier may want to favor the cellular network 10.

[0022] Figure 3 illustrates how the RSSI-Admit threshold is used to control access selection. Figure 3 shows the actual radio coverage area (RCA) of three Wi-Fi cells 60 within the coverage area of a cellular network cell 30. Each Wi-Fi cell 60 also has an effective coverage area (ECA) that is determined by the RSSI-Admit threshold. A user terminal 100 is admitted to the Wi-Fi cell 60 only if the user terminal 100 is within the effective coverage area as determined by the RSSI-Admit threshold. As shown in Figure 3, the RSSI-Admit threshold can be adjusted dynamically to vary the effective coverage area of the Wi-Fi cell 60. The effective coverage area may be increased by lowering the RSSI-Admit threshold, which will increase the number of user terminals 100 admitted to the Wi-Fi cell 60. Conversely, the effective coverage area may be decreased by lowering the RSSI-Admit threshold, which will decrease the number of user terminals 100 admitted to the Wi-Fi cell 60.

[0023] Figure 4 illustrates signaling involved in the correlation of cellular network cells 30 to Wi-Fi cells 60. A user terminal 100 sends an association request to the AP 60 in a Wi-Fi cell 60 to switch its connection from a cellular network cell 30 to the Wi-Fi cell 60 (step 1). In this example, it is assumed that the RSSI is high and that the association request is accepted. In this case, the AP 55 in the Wi-Fi cell 60 sends an association response to the user terminal 100 (step 2). The user terminal 100 then initiates an authentication procedure with an Authentication, Authorization, and Accounting (AAA) server 65 in the WLAN 50 (step 3). The authentication procedure may, for example, use the Extensible Authentication Protocol Subscriber Identity Module (EAP-SIM) method or the Authentication and Key Agreement (AKA) authentication method. If the user terminal 100 is successfully authenticated by the AAA server 65, the AAA server 65 sends an Access Accept message to the AC node 70 in the WLAN 50 (step 4). The Access Accept message includes an authentication response message, such as on EAP Success message, and the IMSI of the user terminal 100. The AC node 70 associates the IMSI of the user terminal 100 with the MAC address of the user terminal 100. The AC node 70 then sends the authentication response message (e.g., EAP Success message) to the user terminal 100 to indicate successful authentication (step 5). Also, upon receipt of the Access Accept message from the AAA server 65, the AC node 70 sends a Cell Identification (ID) Request message to the OSS 35 (step 6). The Cell ID Request message includes the IMSI of user terminal 100 provided by the AAA server 65. In response to the Cell ID Request message, the OSS 35 sends a Cell ID Response message to the AC node (step 7). The Cell ID Response message includes the cell ID of the last known cell 30 in which the user terminal 100 was present. The AC node 70 then performs a cell correlation procedure to map the cell ID to the Wi-Fi cell 60 and update a cell correlation table stored and maintained by the AC node 70. The cell correlation table includes a list of Wi-Fi cells 60 and corresponding cell IDs for cellular network cells 30 that have been correlated with each Wi-Fi cell 60.

[0024] Table 1 below lists functions performed by the OSS 65 and AC node 70 related to cell mapping.
Table 1- Cell Correlation Requirements
NodeRequirementComments
OSS Create table with IMSI, Cell ID, Cell Type and Timestamp when mapping event are received  
OSS Respond to IMSI->Cell ID mapping queries over a Google Buf based interface to AC with Current time is used for AC to compensate for clock differences
 -Latest Cell ID the user terminal was known to be in
 -Type of the cell (GSM/WCDMA/LTE)
 - Coordinated Universal Time (UTC) timestamp for latest time of validity
 -UTC current time
AC Select user terminals with IMSI availability to query for cell ID mapping with the following input: Must select appropriate time to query, taking into consideration event updating on OSS is delayed
 - IMSI of the user terminal
 - Basic Service Set Identification (BSSID) the user terminals is in
AC Create and maintain an AP->Cell ID mapping table Table updating may be once a day or twice a day.
 -Allow up to 9 cells to be mapped to an AP  Cell weight is to be used in calculating weighted average of user terminal 100 average throughput
 -Calculate and maintain a weight on each mapped cell based on primary cell mapping count


[0025] Figure 5 illustrates an exemplary cell correlation method 200 implemented by a network node in the WLAN 50 for correlating cells in first and second access networks. The network node may, for example, comprise an AC node 70 in the WLAN 50. The network node in the WLAN 50 sends a cell ID request to the cellular network 10 (block 210). The Cell ID request includes a user terminal ID (e.g., IMSI) that is used by the user terminal 100 in the cellular network 10. Responsive to the cell identification request, the network node receives a cell ID of a last known cell in the cellular network 10 in which the user terminal 100 was present (block 220). The network node in the WLAN 50 then correlates the received cell ID with a Wi-Fi cell 60 in the WLAN 50 to which the user terminal 100 is currently connected (block 230). The correlation may store in a cell correlation table (block 240).

[0026] Figure 6 illustrates signaling between the cellular network 10 and WLAN 50. The AC node 70 sends a Cell Performance Measurement (PM) Query to the OSS 35 to request performance measurements for the cellular network cells 30 correlated with the Wi-Fi cells 60 within its domain (step 1). The Cell PM Query includes the cell IDs of the cellular network cells 30 correlated with one or more Wi-Fi cells 60 in the WLAN 50. The Cell PM Query may be sent at periodic intervals (e.g., at 1 minute intervals), or may be event triggered. In response to the Cell PM Query, the OSS 35 sends the requested performance measurements for the identified cells to the AC node 70 (step 2). In one exemplary embodiment, the performance measurements comprise the average user terminal throughput Ta for each cellular network cell 30 identified by the request. Alternatively, other performance data could be provided enabling the AC node 70 to compute the average user terminal throughput Ta for each cellular network cell 30. The APs 55 in the WLAN 50 also calculate and report the average user terminal throughput Tw at the same time interval for the respective Wi-Fi cells 60 in the WLAN 50. For each Wi-Fi cell 60, the AC node 70 calculates a weighted average user terminal throughput Tc for the cellular network cells 30 correlated with each Wi-Fi cell 60 and compares it with the average user terminal throughput Tw for the Wi-Fi cell 60 (step 4). Based on the comparison, the AC node 70 adjusts the RSSI-Admit threshold for the Wi-Fi cell 60 and sends the adjusted RSSI-Admit threshold to the AP 55 for the Wi-Fi cell 60 (step 5). The RSSI-Admit threshold is thereafter used by the AP 55 to control admission of user terminals 100 to the Wi-Fi cell 60. Equivalently, the AC node 70 could send the adjustment to the RSSI-Admit threshold to the AP 55 and the AP 55 could add the adjustment to the current RSSI-Admit threshold to obtain the new RSSI-Admit threshold. When the AP 55 receives a request message such as an Authentication Request, Probe Request, or association request from a user terminal 100 (step 6), the AP 55 measures the RSSI for the user terminal 100 and compares the measured RSSI to the RSSI-Admit threshold. If the measured RSSI is less than the threshold, the AP 55 silently rejects the user terminal 100 by dropping the received request messages (step 7). If the RSSI is above the threshold, the AP 55 sends a corresponding response message to the user terminal 100 (step 8).

[0027] Table 2 below provides further details regarding the functions performed by the OSS 35 and AC node 70 related to WiFi/3GPP Access Selection.
Table 2 -Access Selection Requirements
NodeRequirement
OSS Provide external SQL interface for AC to query performance measurements so as to derive average user terminal throughput
AC Query performance measurements through SQL for deriving average user terminal throughput
AC Calculate on-going daily trend of average user terminal throughput for each cell using actual data only
AC Make a statistic prediction of current value of average user terminal throughput from a daily trend and the latest actual values
AC Calculate a predicted current value of weighted user terminal throughput
AC Adaptive RSSI-admit level control loop
AC Communicate with AP to collect user terminal average throughput info and push new RSSI-Admit value to AP
AP Calculate average user terminal throughput and communicate with AC for reporting.
AP Execute commands from AC to activate new RSSI-Admit levels


[0028] Figure 7 illustrates an exemplary method 300 of user network access selection between the WLAN 50 and a cellular network 10 that provides overlapping coverage with the WLAN 50. The method 300 may be performed by AC node 70 in the WLAN 50 or by an AP 55. A performance measurement is obtained for a group of cellular network cells 30 in the cellular network 10 that are correlated with a Wi-Fi cell 60 in the WLAN 50 (block 310). The performance measurement may, for example, comprise the aggregate average user terminal throughput, Tc, for the cellular network cells 30 that are correlated with the Wi-Fi cell 60. An admission threshold (e.g., RSSI-Admit threshold) for the Wi-Fi cell 60 is computed based on the performance measurement for the group of cellular network cells 30 in the cellular network 10 that are correlated with the Wi-Fi cell (block 320). Admission of user terminal 100 attempting to connect to the Wi-Fi cell 60 to the WLAN 50 is controlled based on the admission threshold for the Wi-Fi cell 60 (block 330).

[0029] In some embodiments, the AC node 70 correlates the group of one or more cells 30 in the cellular network 10 with a Wi-Fi cell 60 in the WLAN 50. The AC node 70 may obtain the performance measurement for the cells 30 in the cellular network 10 by requesting individual performance statistics (e.g., per cell average user terminal throughput, Ta) for the correlated cells 30 in the cellular network 10 and computing the performance measurement (e.g., aggregate average user terminal throughput, Tc) for the correlated cellular network cells 30 based on the individual performance statistics. The AC node 70 may further use the performance measurement to compute the admission threshold. To compute the admission threshold, the AC node 70 may also receive a performance measurement (e.g., average user terminal throughput, Tw) for the Wi-Fi cell 60 from the AP 55. The AC node 70 may further control the admission of user terminals 100 to the Wi-Fi cell 60 by sending the computed admission threshold to the AP 55. The AP 55 may then use the admission threshold to determine whether to admit user terminals 100 to the Wi-0Fi cell 60. Alternatively, admission control decisions may be made by the AC node 70. In this case, the AP 55 may send RSSI measurements associated with a user terminal 100 to the AC node 70. The AC node 70 may decide whether to admit the user terminal 100 by comparing the RSSI measurements to the admission threshold.

[0030] In other embodiments, the AP 55 may receive the performance measurement (e.g., aggregate average user terminal throughput, Tc) of the correlated cellular network cells 30 from the AC node 70 and use the performance measurement to compute the admission threshold as previously described. Alternatively, the AP 55 may receive individual performance statistics (e.g., per cell average user terminal throughput, Ta) for correlated cells 30 in the cellular network 10 from either the AC node 70, or from the OSS 35 in the cellular network 10. The AP 55 in this embodiment may compute the performance measurement (e.g. aggregate average user terminal throughput, Tc) for the correlated cellular network cells 30 based on the performance statistics. In embodiments where the admission threshold is computed by the AP 55, the AP 55 may further control admission to the Wi-Fi cell 60 by comparing RSSI measurements for a user terminal 100 attempting to connect to the Wi-Fi cell 60 with the admission threshold.

[0031] Figure 8 illustrates an adaptive control loop for adjusting the admission threshold used for steering traffic between the cellular network 10 and WLAN 50. The average user terminal throughput Ta for cellular network cells 30 correlated with a Wi-Fi cell 60 are input to a processing circuit within the AC node 70. The processing circuit computes the weighted average user terminal throughput, Tc for the cells 30 of the cellular network 10 correlated with a Wi-Fi cell 60. The processing circuit receives the average user terminal throughput, Tw, for the Wi-Fi cell 60 from the AP 55. The processing circuit compares the weighted average throughput Tc for the cellular network cells 30 with the average throughput Tw of the Wi-Fi cell 60. The average user terminal throughput Tw for the Wi-Fi cell 60 may be multiplied by a bias factor b. Based on the comparison, the processing circuit either increments or decrements the RSSI-Admit threshold. In one exemplary embodiment, the RSSI-Admit threshold is incremented or decremented in small steps to avoid oscillation. When the bias factor b is equal to 1, the RSSI-Admit threshold is incremented when Tw is less than Tc and decremented when Tw is greater than Tc. A bias factor b greater than 1 favors the Wi-Fi cell 60, while a bias factor b less than 1 favors the cellular network 10. In one exemplary embodiment, a RSSI-Admit threshold is changed only when the difference between bTw and Tc meets a threshold (e.g. 20% difference). The adjusted RSSI-admit threshold is provided to the AP 55.

[0032] For WCDMA networks, the weighted average user throughput Tc may be computed from the average user throughputs Ta (s) for the individual cellular network cells 30 according to:

where n is the number of cellular network cells 30 correlated to the Wi-Fi cell 60, wi is a normalized weighting factor for the ith cellular network cell 30, and Ta (i) is the average user terminal throughput of the ith cellular network cell 30. The weighting factor wi for cell i may be computed according to:

where hi is the hit count for cell i and the summation in the denominator is the sum of the hit counts for cells 1 through n. The hit count hi for a cellular network cell 30 reflects the degree of overlap between the cellular network cell 30 and the Wi-Fi cell 60 and is computed based on number of times that a user terminal 100 moves from a given cellular network cell 30 to the Wi-Fi cell 60 in a given time interval (e.g., the past one hour or one day). The hit count hi is maintained by the AC node 70 for each cellular network cell 30 that is correlated with a Wi-Fi cell 60. In one exemplary embodiment, the hit count hi for a cellular network cell 30 is incremented each time the cell ID of the cellular network cell 30 is returned by the OSS 35 in response to a Cell ID Request.

[0033] Because the hit counts hi for cellular network cells 30 in the different types of networks may not be directly comparable, the hit counts hi for the cellular network cells 30 may be multiplied by different bias factors depending on the type of the cellular network cells 30. The bias factor may comprise an integer between 1 and 10. A default bias factor of 1 may be used when not otherwise specified. The bias factors are applied to the hit counts before determining the weighting factors for the cellular network cells 30.

[0034] Figures 9A and 9B graphically illustrates the weighted average for the cellular network cells 30 correlated with a Wi-Fi cell 60. Figure 9A shows the average user terminal throughput for three cellular network cells 30 identified as Cell 1, Cell 2 and Cell 3. Figure 9B shows a weighted average user terminal throughput for the same three cellular network cells 30.

[0035] To be comparable to the average user throughput for the cellular network cells 30, the average user terminal throughput for the Wi-Fi cell 60 is based on downlink (DL) data throughput. The downlink data throughput Td and the number of active users is measured and reported every one second. The average user terminal throughput Tw is then calculated every one minute.

[0036] Those skilled in the art will appreciate that although the average user terminal throughput Ta for a cellular network cell 30 and the average user throughput Tw for a Wi-Fi cell 60 may be computed every minute, a longer time window may be used to compute the average. For example, the average user terminal throughputs Ta and Tw may be computed every one minute based on the traffic occurring over the last 15 minutes.

[0037] In actual practice, the latest measurements of the average user terminal throughputs Ta (s) for the cellular network cells 30 available to the AC node 70 for computing the weighted average user terminal throughput Tc may not always be current. The availability of the data may be delayed by as much as 45 minutes for a number of reasons.

[0038] According to one aspect of the present disclosure, a method is provided for predicting the current average user terminal throughput for individual cellular network cells 30 of the cellular network 10 in situations where the available data is not current. The predicted average user terminal throughput for a cell, denoted

, may then be used to compute the weighted average throughput Tc by substituting the predicted average user terminal throughput

for the average user terminal throughput Ta in Eq. (1) to obtain:



[0039] Figure 10 graphically illustrates the prediction of the current average user terminal throughput

for a cellular network cell 30 in one exemplary embodiment. In this embodiment, an on-going daily trend Ttr is calculated for the average user terminal throughput. The latest average user terminal throughout Ta, together with the daily trend Ttr, is then used to predict the current user terminal throughput

.

[0040] In one exemplary embodiment, the daily trend is computed from the average user terminal throughput values collected over a period of days, weeks or months. The daily trend comprises a set of data points at different times t during a one day period. In one exemplary embodiment, the daily trend is computed every one minute by averaging Ta at the same time t over a predetermined number of days. In one exemplary embodiment, the daily trend is computed over a 7 day time window. In some embodiments, a daily trend Ttr may be calculated separately for weekdays, Saturday, and Sunday. Also, a separate daily trend Ttr may be computed for each day of the week if the traffic varies significantly from day to day. A daily trend based on weekdays only is referred to herein as a weekday trend. A daily trend based on the same day of week over a plurality of weeks is referred to herein as a calendar day trend. For example, a daily trend based on data collected each Saturday over a plurality of Saturday is a calendar day trend. The daily trend Ttr at time t is given by:

where n is the number of days over which the daily trend is computed.

[0041] The most recent data for the average user throughput Ta and the daily trend is used to predict a current value of the average user terminal throughput

. The most recent measurements of the average user terminal throughput Ta are averaged over a predetermined time period (e.g. one hour) to obtain a composite average throughput Tavg for the most recent time window. The daily trend is then averaged over the same time window to obtain an average of the daily trend Ttr_avg. The difference between the current value of the daily trend Ttr_current at time t and the average of the daily trend Ttr_avg is computed to obtain ΔTtr. The predicted average user terminal throughout

is given by:



[0042] Other ways of computing the predicated average user terminal throughput could also be used.

[0043] Although the prediction techniques described above were used to predict current average user terminal throughput, those skilled in the art will appreciate that the same techniques can be applied in other contexts and that the prediction techniques can be applied to other situation where the most recent available data is not current.

[0044] Figure 11 illustrates an exemplary method 400 implemented by an AC node 70 or other network node for predicting a current value of a performance measurement indicative of network performance. The AC node 70 or other network node obtains a daily trend in a series of performance measurements (block 410). The daily trend comprises a set of data points at different times of day, wherein each data point represents an average value of the performance measurements at a corresponding time of day over a plurality of days. The AC node 70 or other network node also obtains one or more recent performance measurements over a recent time interval (block 420). Based on the daily trend and the recent performance measurements, the AC node 70 or other network node predicts the current value of the performance measurement (block 430).

[0045] Figure 12 illustrates an exemplary network node 500 for implementing traffic steering as herein described. The network node 500 comprises a network interface circuit 510 for connecting to a communication network and communicating over the network with other network nodes, and a processing circuit 520 configured to perform one or more of the methods described herein. In one embodiment, the network node 500 functions as an AC node 70 as herein described. In other embodiments, the network node 500 functions an AP 55 in the WLAN 50 as herein described and further includes a transceiver 530 for communicating with user terminals 100 over a radio interface. In other embodiments, the network node 200 comprises an OSS 35 in the cellular network 10 and the processing circuit 220 is configured to provide an AC node 70 or AP 55 in the WLAN 50 with cell IDs and performance statistics as herein described.


Claims

1. A method of controlling selection by a user terminal (100) between a Wireless Local Area Network, WLAN, network (50) and a cellular network (10) providing overlapping coverage with the WLAN network (50), the method being performed in a network node in the WLAN network and comprising:

obtaining (310) a performance measurement for a group of one or more cells (30) in the cellular network (10) that are correlated with a cell (60) in the WLAN network, wherein a cell ID of a last known cell in the cellular network (10) in which the user terminal (100) was present is correlated with the cell (60) in the WLAN network (50) to which the user terminal (100) is currently connected;

increasing or decreasing (320) a Received Signal Strength Indicator, RSSI, admission threshold for the cell (60) in the WLAN network (50) based on the performance measurement; and

controlling (330) the admission of a user terminal (100) operating in the cellular network (10) to the cell (60) in the WLAN network (50) based on the RSSI admission threshold.


 
2. The method of claim 1 wherein the RSSI admission threshold comprises a minimum received signal strength for the user terminal (100) allowed by the cell (60) in the WLAN network (50).
 
3. A network node (70) in a Wireless Local Area Network, WLAN, network (50) configured to control selection by a user terminal (100) between the WLAN network (50) and a cellular network (10) providing overlapping coverage with the WLAN network (50), the network node (70) comprising:

a network interface for communicating with other network nodes; and

a processing circuit configured to:

obtain (310) a performance measurement for a group of one or more cells (30) in the cellular network (10) that are correlated with a cell (60) in the WLAN network, wherein a cell ID of a last known cell in the cellular network (10) in which the user terminal (100) was present is correlated with the cell (60) in the WLAN network (50) to which the user terminal (100) is currently connected;

increase or decrease (320) a Received Signal Strength Indicator, RSSI, admission threshold for a cell (60) in the WLAN network (50) based on the performance measurement for the group of cells (30) in the cellular network (10); and

control (330) the admission of a user terminal (100) operating in the cellular network (10) to the cell (60) in the WLAN network (50) based on the RSSI admission threshold.


 
4. The network node (70) of claim 3wherein, to increase or decrease an RSSI admission threshold for the cell (60) in the WLAN network (50) based on a performance measurement for the group of cells (30) in the cellular network (10), the processing circuit is configured to increase or decrease the RSSI admission threshold based on the average throughput for the group of cells (30) in the cellular network (10).
 
5. The network node (70) of claim 4 wherein, to increase or decrease the RSSI admission threshold based on the average throughput for the group of cells (30) in the cellular network (10), the processing circuit is configured to increase or decrease the RSSI admission threshold further based on the average throughput of the cell (60) in the WLAN network (50); and
wherein, optionally, to increase or decrease the RSSI admission threshold based on the average throughput for the group of cells (30) in the cellular network (10), the processing circuit is configured to apply bias factors to favor one of the first and cellular networks (10; 50).
 
6. The network node (70) of claim 4 wherein, to compute an average throughput for a group of cells (30) in the cellular network (10), the processing circuit is configured to compute a weighted average throughput for the group of cells (30) in the cellular network (10).
 
7. The network node (70) of claim 6 wherein, to compute a weighted average throughput for the group of cells (30) in the cellular network (10), the processing circuit is configured to:

compute a weighting factor for each cell (30) in the group;

compute a weighted sum of the individual cell (30) throughputs based on the weighing factors; and

divide the weighted sum by the number of cells (30) in the group of cells (30).


 
8. The network node (70) of claim 7 wherein, to compute a weighting factor for each cell (30) in the group, the processing circuit is configured to compute the weighting factors based on hit counts, the hit counts reflecting the degree of overlap between the cell (30) in the cellular network and the cell (60) in the WLAN network (50) and being computed based on number of times that a user terminal (100) moves from the cell (30) in the cellular network (10) to the cell (60) in the WLAN network (50) in a given time interval; and
wherein, optionally, to compute the weighting factors based on hit counts, the processing circuit is configured to multiply the hit counts for cells (30) of different types by corresponding bias factors based on cell type.
 
9. The network node (70) of any of claims 3 to 8 wherein, to increase or decrease the RSSI admission threshold based on a performance measurement for the group of cells (30) in the cellular network (10), the processing circuit is configured to increase or decrease the RSSI admission threshold further based on cell load factors or other network conditions in the first and cellular networks (10; 50).
 
10. The network node (70) of any of claims 3 to 9 wherein the network node (70) comprises a centralized Wi-Fi access control node configured to increase or decrease the RSSI admission thresholds for two or more cells (30) in the cellular network (10); and
wherein, optionally, to control the admission of a user terminal (100) operating in a cell (30) of the cellular network (10) to the cell (60) in the WLAN network (50) based on the RSSI admission threshold, the processing circuit is configured to send the RSSI admission threshold from the access control node to an access point.
 
11. The network node (70) of any of claims 3 to 10 wherein the network node (70) comprises an access point in a cell (30) of the cellular network (10).
 
12. The network node (70) of claim 11 wherein, to control the admission of a user terminal (100) operating in a cell (30) of the cellular network (10) to the cell (60) in the WLAN network (50) based on the RSSI admission threshold, the processing circuit is configured to:

measure an RSSI of a signal received from a user terminal (100) attempting to access the cell (60) in the WLAN network (50);

admit the user terminal (100) to the cell (60) in the WLAN network (50) based on a comparison of the received signal strength to the RSSI admission threshold; and

wherein, optionally, the processing circuit is further configured to silently reject the attempt by a user terminal (100) to make connection attempt to the WLAN network from the user terminal (100).


 
13. The network node (70) of claim 11 wherein, to obtain a performance measurement for a group of one or more cells (30) in the cellular network (10) that are correlated with the cell (60) in the WLAN network, the processing circuit is configured to:

receive performance statistics for the group of cells (30) in the cellular network (10) correlated with the cell (60) in the WLAN network (50); and

compute the performance measurement based on the performance statistics.


 
14. The network node (70) of any of claims 3 to 13 wherein the processing circuit is configured to re adjust the RSSI admission threshold at predetermined intervals or as conditions in the two access networks change.
 


Ansprüche

1. Verfahren zum Steuern der Auswahl durch ein Benutzerendgerät (100) zwischen einem drahtlosen lokalen Netzwerk, WLAN-Netz, (50) und einem zellularen Netz (10), das eine überlappende Abdeckung mit dem WLAN-Netz (50) bereitstellt, wobei das Verfahren in einem Netzknoten im WLAN-Netz durchgeführt wird und Folgendes umfasst:

Erhalten (310) einer Leistungsmessung für eine Gruppe von einer oder mehreren Zellen (30) im zellularen Netz (10), die mit einer Zelle (60) im WLAN-Netz korreliert sind, wobei eine Zellen-ID einer letzten bekannten Zelle im zellularen Netz (10), in dem das Benutzerendgerät (100) vorhanden war, mit der Zelle (60) im WLAN-Netz (50) korreliert ist, mit der das Benutzerendgerät (100) aktuell verbunden ist;

Erhöhen oder Verringern (320) eines Aufnahmeschwellenwerts der Empfangssignalstärkeanzeige, RSSI, für die Zelle (60) im WLAN-Netz (50) basierend auf der Leistungsmessung; und

Steuern (330) der Aufnahme eines im zellularen Netz (10) betriebenen Benutzerendgerätes (100) in die Zelle (60) im WLAN-Netz (50) basierend auf dem RSSI-Aufnahmeschwellenwert.


 
2. Verfahren nach Anspruch 1, wobei der RSSI-Aufnahmeschwellenwert eine minimale Empfangssignalstärke für das Benutzerendgerät (100) umfasst, die von der Zelle (60) in dem WLAN-Netz (50) zugelassen wird.
 
3. Netzknoten (70) in einem drahtlosen lokalen Netz, WLAN-Netz, (50), der konfiguriert ist, um die Auswahl durch ein Benutzerendgerät (100) zwischen dem WLAN-Netz (50) und einem zellularen Netz (10) zu steuern, das eine überlappende Abdeckung mit dem WLAN-Netz (50) bereitstellt, wobei der Netzknoten (70) Folgendes umfasst:

eine Netzschnittstelle zur Kommunikation mit anderen Netzknoten; und

eine Verarbeitungsschaltung, die konfiguriert ist zum:

Erhalten (310) einer Leistungsmessung für eine Gruppe von einer oder mehreren Zellen (30) im zellularen Netz (10), die mit einer Zelle (60) im WLAN-Netz korreliert sind, wobei eine Zellen-ID einer letzten bekannten Zelle im zellularen Netz (10), in dem das Benutzerendgerät (100) vorhanden war, mit der Zelle (60) im WLAN-Netz (50) korreliert ist, mit der das Benutzerendgerät (100) aktuell verbunden ist;

Erhöhen oder Verringern (320) eines Aufnahmeschwellenwerts der Empfangssignalstärkeanzeige, RSSI, für eine Zelle (60) im WLAN-Netz (50) basierend auf der Leistungsmessung für die Gruppe von Zellen (30) im zellularen Netz (10); und

Steuern (330) der Aufnahme eines im zellularen Netz (10) betriebenen Benutzerendgerätes (100) in die Zelle (60) im WLAN-Netz (50) basierend auf dem RSSI-Aufnahmeschwellenwert.


 
4. Netzknoten (70) nach Anspruch 3, wobei zum Erhöhen oder Verringern eines RSSI-Aufnahmeschwellenwerts für die Zelle (60) im WLAN-Netz (50) basierend auf einer Leistungsmessung für die Gruppe von Zellen (30) im zellularen Netz (10) die Verarbeitungsschaltung konfiguriert ist, um den RSSI-Aufnahmeschwellenwert basierend auf dem durchschnittlichen Durchsatz für die Gruppe von Zellen (30) im zellularen Netz (10) zu erhöhen oder zu verringern.
 
5. Netzknoten (70) nach Anspruch 4, wobei zum Erhöhen oder Verringern des RSSI-Aufnahmeschwellenwerts basierend auf dem durchschnittlichen Durchsatz für die Gruppe von Zellen (30) im zellularen Netz (10) die Verarbeitungsschaltung konfiguriert ist, um den RSSI-Aufnahmeschwellenwert weiter basierend auf dem durchschnittlichen Durchsatz der Zelle (60) im WLAN-Netz (50) zu erhöhen oder zu verringern; und
wobei wahlweise zum Erhöhen oder Verringern des RSSI-Aufnahmeschwellenwerts basierend auf dem durchschnittlichen Durchsatz für die Gruppe von Zellen (30) im zellularen Netz (10) die Verarbeitungsschaltung konfiguriert ist, um Vorspannungsfaktoren zugunsten eines der ersten und zellularen Netze (10; 50) anzuwenden.
 
6. Netzknoten (70) nach Anspruch 4, wobei zum Berechnen eines durchschnittlichen Durchsatzes für eine Gruppe von Zellen (30) in dem zellularen Netz (10) die Verarbeitungsschaltung konfiguriert ist, um einen gewichteten durchschnittlichen Durchsatz für die Gruppe von Zellen (30) in dem zellularen Netz (10) zu berechnen.
 
7. Netzknoten (70) nach Anspruch 6, wobei zum Berechnen eines gewichteten durchschnittlichen Durchsatzes für die Gruppe von Zellen (30) in dem zellularen Netz (10) die Verarbeitungsschaltung konfiguriert ist zum:

Berechnen eines Gewichtungsfaktors für jede Zelle (30) in der Gruppe;

Berechnen einer gewichteten Summe der Durchsätze der einzelnen Zellen (30) basierend auf den Gewichtungsfaktoren; und

Teilen der gewichteten Summe durch die Anzahl der Zellen (30) in der Gruppe der Zellen (30).


 
8. Netzknoten (70) nach Anspruch 7, wobei zur Berechnung eines Gewichtungsfaktors für jede Zelle (30) in der Gruppe die Verarbeitungsschaltung konfiguriert ist, um die Gewichtungsfaktoren basierend auf Treffern zu berechnen, wobei die Treffer den Überlappungsgrad zwischen der Zelle (30) im zellularen Netz und der Zelle (60) im WLAN-Netz (50) widerspiegeln und basierend auf der Anzahl der Male berechnet werden, die sich ein Benutzerendgerät (100) von der Zelle (30) im zellularen Netz (10) zu der Zelle (60) im WLAN-Netz (50) in einem gegebenen Zeitintervall bewegt; und
wobei zum Berechnen der Gewichtungsfaktoren basierend auf Treffern die Verarbeitungsschaltung optional konfiguriert ist, um die Treffer für Zellen (30) verschiedener Typen mit entsprechenden Vorspannungsfaktoren basierend auf dem Zelltyp zu multiplizieren.
 
9. Netzknoten (70) nach einem der Ansprüche 3 bis 8, wobei zum Erhöhen oder Verringern des RSSI-Aufnahmeschwellenwerts basierend auf einer Leistungsmessung für die Gruppe von Zellen (30) im zellularen Netz (10) die Verarbeitungsschaltung konfiguriert ist, um den RSSI-Aufnahmeschwellenwert ferner basierend auf Zelllastfaktoren oder anderen Netzbedingungen in den ersten und zellularen Netzen (10; 50) zu erhöhen oder zu verringern.
 
10. Netzknoten (70) nach einem der Ansprüche 3 bis 9, wobei der Netzknoten (70) einen zentralisierten Wi-Fi-Zugangssteuerknoten umfasst, der konfiguriert ist, um die RSSI-Aufnahmeschwellenwerte für zwei oder mehr Zellen (30) in dem zellularen Netz (10) zu erhöhen oder zu verringern; und
wobei wahlweise zum Steuern der Aufnahme eines Benutzerendgerätes (100), das in einer Zelle (30) des zellularen Netzes (10) betrieben wird, in die Zelle (60) des WLAN-Netzes (50) basierend auf dem RSSI-Aufnahmeschwellenwert die Verarbeitungsschaltung konfiguriert ist, um den RSSI-Aufnahmeschwellenwert von dem Zugangssteuerknoten zu einem Zugangspunkt zu senden.
 
11. Netzknoten (70) nach einem der Ansprüche 3 bis 10, wobei der Netzknoten (70) einen Zugangspunkt in einer Zelle (30) des zellularen Netzes (10) umfasst.
 
12. Netzknoten (70) nach Anspruch 11, wobei zum Steuern der Aufnahme eines Benutzerendgerätes (100), das in einer Zelle (30) des zellularen Netzes (10) betrieben wird, in die Zelle (60) in dem WLAN-Netz (50) basierend auf dem RSSI-Aufnahmeschwellenwert, die Verarbeitungsschaltung konfiguriert ist zum:

Messen einer RSSI eines Signals, das von einem Benutzerendgerät (100) empfangen wird, das versucht, auf die Zelle (60) im WLAN-Netz (50) zuzugreifen;

Zulassen des Benutzerendgeräts (100) zu der Zelle (60) im WLAN-Netz (50) basierend auf einem Vergleich der Empfangssignalstärke mit dem RSSI-Aufnahmeschwellenwert; und

wobei wahlweise die Verarbeitungsschaltung ferner konfiguriert ist, um den Versuch eines Benutzerendgerätes (100), einen Verbindungsversuch mit dem WLAN-Netz von dem Benutzerendgerät (100) aus durchzuführen, stillschweigend abzulehnen.


 
13. Netzknoten (70) nach Anspruch 11, wobei zum Erhalten einer Leistungsmessung für eine Gruppe von einer oder mehreren Zellen (30) im zellularen Netz (10), die mit der Zelle (60) im WLAN-Netz korreliert sind, die Verarbeitungsschaltung konfiguriert ist zum:

Empfangen von Leistungsstatistiken für die Gruppe von Zellen (30) in dem zellularen Netz (10), die mit der Zelle (60) in dem WLAN-Netz (50) korreliert sind; und

Berechnen der Leistungsmessung basierend auf der Leistungsstatistik.


 
14. Netzknoten (70) nach einem der Ansprüche 3 bis 13, wobei die Verarbeitungsschaltung konfiguriert ist, um den RSSI-Aufnahmeschwellenwert in vorbestimmten Intervallen oder bei sich ändernden Bedingungen in den beiden Zugangsnetzen neu einzustellen.
 


Revendications

1. Procédé de commande de sélection par un terminal utilisateur (100) entre un réseau de réseau local sans fil, WLAN (50) et un réseau cellulaire (10) fournissant une couverture en chevauchement avec le réseau WLAN (50), le procédé étant mis en oeuvre dans un noeud de réseau dans le réseau WLAN et comprenant :

l'obtention (310) d'une mesure de performance pour un groupe d'une ou plusieurs cellules (30) dans le réseau cellulaire (10) qui sont corrélées à une cellule (60) dans le réseau WLAN, dans lequel un ID cellule d'une dernière cellule connue dans le réseau cellulaire (10) dans lequel le terminal utilisateur (100) était présent est corrélé à la cellule (60) dans le réseau WLAN (50) auquel le terminal utilisateur (100) est actuellement connecté ;

l'augmentation ou la diminution (320) du seuil d'admission d'indicateur de force de signal reçu, RSSI, pour la cellule (60) dans le réseau WLAN (50) sur la base de la mesure de performance ; et

la commande (330) de l'admission d'un terminal utilisateur (100) fonctionnant dans le réseau cellulaire (10) vers la cellule (60) dans le réseau WLAN (50) sur la base du seuil d'admission RSSI.


 
2. Procédé selon la revendication 1 dans lequel le seuil d'admission RSSI comprend une force minimale de signal reçu pour le terminal utilisateur (100) autorisée par la cellule (60) dans le réseau WLAN (50).
 
3. Noeud de réseau (70) dans un réseau de réseau local sans fil, WLAN (50) configuré pour commander la sélection par un terminal utilisateur (100) entre le réseau WLAN (50) et un réseau cellulaire (10) fournissant une couverture en chevauchement avec le réseau WLAN (50), le noeud de réseau (70) comprenant :

une interface réseau pour communiquer avec d'autres noeuds de réseau ; et

un circuit de traitement configuré pour :

obtenir (310) une mesure de performance pour un groupe d'une ou plusieurs cellules (30) dans le réseau cellulaire (10) qui sont corrélées à une cellule (60) dans le réseau WLAN, dans lequel un ID cellule d'une dernière cellule connue dans le réseau cellulaire (10) dans lequel le terminal utilisateur (100) était présent est corrélé à la cellule (60) dans le réseau WLAN (50) auquel le terminal utilisateur (100) est actuellement connecté ;

augmenter ou diminuer (320) un seuil d'admission d'indicateur de force de signal reçu, RSSI, pour une cellule (60) dans le réseau WLAN (50) sur la base de la mesure de performance pour le groupe de cellules (30) dans le réseau cellulaire (10) ; et

commander (330) l'admission d'un terminal utilisateur (100) fonctionnant dans le réseau cellulaire (10) vers la cellule (60) dans le réseau WLAN (50) sur la base du seuil d'admission RSSI.


 
4. Noeud de réseau (70) selon la revendication 3 dans lequel, pour augmenter ou diminuer un seuil d'admission RSSI pour la cellule (60) dans le réseau WLAN (50) sur la base d'une mesure de performance pour le groupe de cellules (30) dans le réseau cellulaire (10), le circuit de traitement est configuré pour augmenter ou diminuer le seuil d'admission RSSI sur la base du débit moyen pour le groupe de cellules (30) dans le réseau cellulaire (10).
 
5. Noeud de réseau (70) selon la revendication 4 dans lequel, pour augmenter ou diminuer le seuil d'admission RSSI sur la base du débit moyen pour le groupe de cellules (30) dans le réseau cellulaire (10), le circuit de traitement est configuré pour augmenter ou diminuer le seuil d'admission RSSI sur la base en outre du débit moyen de la cellule (60) dans le réseau WLAN (50) ; et
dans lequel, facultativement, pour augmenter ou diminuer le seuil d'admission RSSI sur la base du débit moyen pour le groupe de cellules (30) dans le réseau cellulaire (10), le circuit de traitement est configuré pour appliquer des facteurs de tendance pour favoriser l'un parmi le premier réseau et le réseau cellulaire (10 ; 50).
 
6. Noeud de réseau (70) selon la revendication 4 dans lequel, pour calculer un débit moyen pour un groupe de cellules (30) dans le réseau cellulaire (10), le circuit de traitement est configuré pour calculer un débit moyen pondéré pour le groupe de cellules (30) dans le réseau cellulaire (10).
 
7. Noeud de réseau (70) selon la revendication 6 dans lequel, pour calculer un débit moyen pondéré pour le groupe de cellules (30) dans le réseau cellulaire (10), le circuit de traitement est configuré pour :

calculer un facteur de pondération pour chaque cellule (30) dans le groupe ;

calculer une somme pondérée des débits de la cellule individuelle (30) sur la base des facteurs de pondération ; et

diviser la somme pondérée par le nombre de cellules (30) dans le groupe de cellules (30).


 
8. Noeud de réseau (70) selon la revendication 7 dans lequel, pour calculer un facteur de pondération pour chaque cellule (30) dans le groupe, le circuit de traitement est configuré pour calculer les facteurs de pondération sur la base de comptages de correspondances, les comptages de correspondances reflétant le degré de chevauchement entre la cellule (30) dans le réseau cellulaire et la cellule (60) dans le réseau WLAN (50) et étant calculés sur la base du nombre de fois qu'un terminal utilisateur (100) passe de la cellule (30) dans le réseau cellulaire (10) à la cellule (60) dans le réseau WLAN (50) dans un intervalle de temps donné ; et
dans lequel, facultativement, pour calculer les facteurs de pondération sur la base de comptages de correspondances, le circuit de traitement est configuré pour multiplier les comptages de correspondances pour des cellules (30) de types différents par des facteurs de tendance correspondants sur la base du type de cellule.
 
9. Noeud de réseau (70) selon l'une quelconque des revendications 3 à 8 dans lequel, pour augmenter ou diminuer le seuil d'admission RSSI sur la base d'une mesure de performance pour le groupe de cellules (30) dans le réseau cellulaire (10), le circuit de traitement est configuré pour augmenter ou diminuer le seuil d'admission RSSI en outre sur la base de facteurs de charge de cellule ou d'autres conditions de réseau dans le premier réseau et le réseau cellulaire (10 ; 50).
 
10. Noeud de réseau (70) selon l'une quelconque des revendications 3 à 9 dans lequel le noeud de réseau (70) comprend un noeud de commande d'accès Wi-Fi centralisé configuré pour augmenter ou diminuer les seuils d'admission RSSI pour deux cellules ou plus (30) dans le réseau cellulaire (10) ; et dans lequel, facultativement, pour commander l'admission d'un terminal utilisateur (100) fonctionnant dans une cellule (30) du réseau cellulaire (10) à la cellule (60) dans le réseau WLAN (50) sur la base du seuil d'admission RSSI, le circuit de traitement est configuré pour envoyer le seuil d'admission RSSI depuis le noeud de commande d'accès vers un point d'accès.
 
11. Noeud de réseau (70) selon l'une quelconque des revendications 3 à 10 dans lequel le noeud de réseau (70) comprend un point d'accès dans une cellule (30) du réseau cellulaire (10).
 
12. Noeud de réseau (70) selon la revendication 11 dans lequel, pour commander l'admission d'un terminal utilisateur (100) fonctionnant dans une cellule (30) du réseau cellulaire (10) à la cellule (60) dans le réseau WLAN (50) sur la base du seuil d'admission RSSI, le circuit de traitement est configuré pour :

mesurer le RSSI d'un signal reçu d'un terminal utilisateur (100) tentant d'accéder à la cellule (60) dans le réseau WLAN (50) ;

admettre le terminal utilisateur (100) à la cellule (60) dans le réseau WLAN (50) sur la base d'une comparaison de la force de signal reçu au seuil d'admission RSSI ; et

dans lequel, facultativement, le circuit de traitement est en outre configuré pour rejeter de façon silencieuse la tentative par un terminal utilisateur (100) pour réaliser une tentative de connexion au réseau WLAN depuis le terminal utilisateur (100).


 
13. Noeud de réseau (70) selon la revendication 11 dans lequel, pour obtenir une mesure de performance pour un groupe d'une ou plusieurs cellules (30) dans le réseau cellulaire (10) qui sont corrélées à la cellule (60) dans le réseau WLAN, le circuit de traitement est configuré pour :

recevoir des statistiques de performance pour le groupe de cellules (30) dans le réseau cellulaire (10) corrélées avec la cellule (60) dans le réseau WLAN (50) ; et

calculer la mesure de performance sur la base des statistiques de performance.


 
14. Noeud de réseau (70) selon l'une quelconque des revendications 3 à 13 dans lequel le circuit de traitement est configuré pour réajuster le seuil d'admission RSSI à des intervalles prédéterminés ou lorsque des conditions dans les deux réseaux d'accès changent.
 




Drawing







































REFERENCES CITED IN THE DESCRIPTION



This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description




Non-patent literature cited in the description