KR20110073577A - Location-based, event triggered inter-radio access technology handovers from a cdma macrocell to a wcdma femtocell - Google Patents

Abstract

The present invention provides a method for implementation in a mobile unit configured to communicate with a wireless communication system comprising macrocells and femtocells. Macrocells and femtocells use different generations of radio access technologies. The method includes determining a distance between the mobile unit and the femtocell (s) and transmitting a first measurement report when the distance between the mobile unit and the femtocell (s) is less than the threshold distance. The method also includes performing an inter-radio access handoff from the base transceiver station to the femtocell when the distance is less than the threshold distance.

Description

LOCATION-BASED, EVENT TRIGGERED INTER-RADIO ACCESS TECHNOLOGY HANDOVERS FROM A CDMA MACROCELL TO A WCDMA FEMTOCELL}

Cross Reference to Related Applications

The present invention is filed on Nov. 5, 2008 and is entitled “Location-Based Handovers from Macrocell to Femtocell Using Event-Triggered Measurement Report”, and the inventors describe Christian Demetrescu and Suat S. Is associated with US patent application 12 / 265,089 (2100.043000).

The present invention is filed on Nov. 5, 2008, and is entitled “Location-Based Handovers from Macrocell to Femtocell Using Periodic Measurement Reporting”, and the inventors named Christian Demetrescu and Suat Eskisiogluin. US Patent Application No. 12 / 265,136 (2100.043100).

The present invention is filed on Nov. 5, 2008, and entitled “Method for associating a cluster of first femtocells with user equipment”, the inventors of the US patent application claiming Christian Demetrescu and Suat Eskisioglu. 12 / 265,173 (2100.043300).

The present invention is filed on Nov. 5, 2008, and entitled “Method for associating a first femtocell with user equipment”, the inventors of Christian Demetrescu and Suat Eskisioglu US Patent Application No. 12 / 265,215 (2100.043400).

The invention is filed on Nov. 18, 2008, and is entitled “Periodic Reporting for Location-Based Handovers Between Radio Access Technologies from GSM Macrocells to WCDMA Femtocells”, and inventors Christian Demetrescu and Suart Eskisiogluin, US patent application Ser. No. 12 / 272,929 (2100.043600).

The present invention relates generally to communication systems, in particular wireless communication systems.

Conventional wireless communication systems use a network of base stations to provide wireless connectivity for one or more mobile units. In some cases, mobile units may initiate wireless communication with one or more base stations in the network, for example, when a user of the mobile unit wants to initiate a voice or data call. Alternatively, the network may initiate a wireless communication link with the mobile unit. For example, in conventional hierarchical wireless communications, a server transmits voice and / or data destined for a target mobile unit to a central element such as a base station controller (BSC). The BSC may then transmit paging messages to the target mobile unit via one or more base station transceivers or BTSs. The target mobile unit may establish a wireless link for one or more base station transceivers in response to receiving the page from the wireless communication system. The radio resource management function within the BSC receives voice and / or data and coordinates the radio and time resources used by the set of base station transceivers to send information to the target mobile unit. The radio resource management function may execute fine control to allocate and release resources for broadcast transmission on a set of base station transceivers.

Conventional base stations provide wireless connectivity within geographic areas called cells, macrocells, and / or sectors. Conventional base station transceivers may transmit signals using a predetermined amount of available transmit power. The range of a macrocell is determined by a number of factors including available transmission power, each distribution of available power, obstacles in the macrocell, environmental conditions, and the like. For example, the range of macrocells can range from as small as 300 m in dense urban environments to as much as 10 km in sparsely populated rural environments. If any of these parameters are changed, the coverage area may also change in time.

One alternative to the conventional hierarchical network architecture is a distributed architecture that includes a network of access points such as base station routers that implement distributed communication network functionality. For example, each base station router may combine Radio Network Controller (RNC) and / or PDSN functions into a single entity that manages wireless links between one or more mobile units and an external network such as the Internet. Base station routers can fully encapsulate cellular access technology and can represent functionality using core network device support for equivalent IP functions. For example, IP anchoring in a UMTS base station router may be provided through mobile IP home agent (HA) and GGSN anchoring functions that the base station router substitutes through equivalent mobile IP signaling. Compared with hierarchical networks, distributed architectures have the cost and / or complexity of deploying a network, and the cost and / or cost of adding additional wireless access points, eg, base station routers, to extend the coverage of an existing network. Has the potential to reduce complexity. Distributed networks can also reduce (as compared to hierarchical networks) users experience because packet queuing delays in separate RNC and PDSN entities in hierarchical networks can be reduced or eliminated. .

Because at least in part the cost and complexity of deploying a base station router is reduced, the base station routers may be deployed in locations that were impractical for conventional base stations. For example, a base station router may be deployed in a house or building to provide wireless connectivity for the occupants of the occupants of the building. Base station routers deployed in a home are generally referred to as home base station routers or femtocells because they are intended to provide wireless connectivity to a much smaller area (eg, femtocell) that contains a home. Femtocells have a much smaller power output than conventional base stations used to provide coverage for macrocells. For example, a typical femtocell has a transmit power of about 10 GHz. As a result, the range of a typical femtocell is much smaller than that of a macrocell. For example, a typical range of femtocells is about 100 meters. Clusters of femtocells may also be deployed to provide coverage for larger areas and / or more users.

Femtocells are expected to be deployed with a macro-cellular network in an overlay configuration. For example, a macro-cellular network can be used to provide wireless connectivity for a neighborhood containing multiple homes. Any mobile unit located in one of the homes or moving between neighbors can access a wireless communication system using a macro-cellular network. Individual femtocells may be placed in one or more houses to provide overlay coverage in (or nearby) the house. Clusters of femtocells may also be deployed in one or more buildings to provide overlay coverage within (or near) the building. In another case, there will be a one-to-many relationship between macrocells and femtocells within the coverage area. However, mobile units will generally be authorized to stay only in selected femtocells. For example, mobile units operated by individual users may be authorized to stay in the cell cells that were installed by users in their homes. In another example, mobile units operated by employees may be authorized to stay in femtocells in a femtocell cluster installed by a business.

In many cases, parts of existing macro-cellular networks are in place for a period of time, and thus can be implemented using previous generations of radio access technologies. As a result, relatively recently installed femtocells can use a more recent generation of radio access technology than conventional macrocells. For example, a wireless communication system may include second generation macrocells and third generation femtocells. Because the user travels across the geographic areas served by the macrocells and femtocells, wireless access to handoff the mobile unit between 2nd generation (2G) macrocells and 3rd generation (3G) femtocells Inter-RAT handoffs may be needed. Conventional communication systems use the availability of radio resources and / or radio conditions to determine when to perform a handoff between radio access technologies. For example, channel qualities and / or signal strengths may be measured using signals transmitted between the mobile unit and the macrocells and / or femtocells. Conventional systems provide from a macrocell to a femtocell when the channel qualities and / or signal strengths for signals transmitted by the macrocells are poor compared to the measured channel qualities and / or signal strengths for the femtocells. Hand off the mobile unit.

However, conventional inter-RAT handoff standards do not distinguish between normal femtocells, femtocells and macrocells associated with specific mobile units. As a result, mobile units may not be handed off to authorized home and / or business femtocells, even if the user is in a home or business covered by the associated femtocell, provided that the wireless conditions in the macro-cellular network are of high quality. have. For example, radio conditions in a macro-cellular network may maintain high enough quality to prevent virtually all inter-RAT handovers to a femtocell, for example when the femtocell is placed in the center of the macrocell coverage area. have.

The disclosed subject matter relates to addressing the effects of one or more of the problems presented above. The following presents a brief summary of the disclosed subject matter in order to provide a basic understanding of some aspects of the disclosed subject matter. This summary is not an exhaustive overview of the disclosed subject matter. It is not intended to identify key or critical elements of the disclosed subject matter or to delineate the scope of the disclosed subject matter. Its purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is discussed below.

In one embodiment, a method is provided for implementation in a mobile unit configured to communicate with a wireless communication system including macrocells and femtocells. Macrocells and femtocells use different radio access technologies. The method includes determining a distance between the mobile unit and the femtocell (s), and transmitting a first measurement report when the distance between the mobile unit and the femtocell (s) is less than the threshold distance. The method also includes performing an inter-radio access handoff from the base transceiver station to the femtocell when the distance is less than the threshold distance.

In yet another embodiment, a method for implementation in a base station controller configured for deployment in a wireless communication system including macrocells and femtocells is provided. Macrocells and femtocells use different radio access technologies. The method includes receiving a first measurement report when the distance between the mobile unit and the femtocell is less than the threshold distance. The method further includes executing a handoff between the radio access technologies of the mobile unit from the base transceiver station to the femtocell when the distance between the mobile unit and the femtocell is less than the threshold distance.

The disclosed subject matter can be understood with reference to the following detailed description taken in conjunction with the accompanying drawings, wherein like reference numerals identify the same elements.

1 conceptually illustrates a first exemplary embodiment of a wireless communication system;
2 conceptually illustrates a second exemplary embodiment of a wireless communication system;
3 conceptually illustrates a first exemplary embodiment of a method of handing off a mobile unit between a macrocell and a femtocell using event-based triggering;

While the disclosed subject matter is capable of various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and are described in detail below. However, the description herein of specific embodiments is not intended to limit the disclosed subject matter to the particular forms disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the scope of the appended claims.

Example embodiments are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. Of course, in the development of any such practical embodiment, multiple implementation-specific to achieve specific goals of the developer, such as adherence to system-related and business-related constraints that will change from one implementation to another. It will be appreciated that decisions should be made. In addition, while such development efforts will be complex and time-consuming, it will nevertheless be appreciated that it will be routine for those skilled in the art to benefit from the present disclosure.

Referring now to the accompanying drawings, the disclosed subject matter will be described. Various structures, systems and devices are schematically depicted in the drawings for purposes of illustration only and so as to not obscure the present invention with respect to details that are known to those skilled in the art. Nevertheless, the attached drawings are included to describe and explain illustrative examples of the disclosed subject matter. The words and phrases used herein are to be understood and interpreted to have a meaning consistent with the understanding of those words and phrases by those skilled in the art. The specific provisions of the term or phrase, ie, those that differ from the general and common meaning as understood by those skilled in the art, are not implied by the consistent use of the term or phrase herein. To the extent that terms or phrases have special meanings, that is, different meanings to those skilled in the art, such particular provisions will be expressly set forth herein in a prescriptive manner that directly and explicitly provides particular provisions for such terms or phrases. will be.

1 conceptually illustrates a first exemplary embodiment of a wireless communication system 100. In the illustrated embodiment, the base station transceiver (BTS) 105 provides wireless connectivity to the plurality of macrocells 110 (1)-110 (3). Indexes 1-3 may be used to identify individual elements, such as macrocell 110 (1) or subsets of elements, although these indices collectively refer to macrocells 110. May be omitted. This convenience may apply to other elements shown in the figures and may be mentioned in the use of identification numbers and one or more distinct indices. In the illustrated embodiment, macrocells 110 operate in accordance with second generation (2G) standards and / or protocols, such as code division multiple access (CDMA). However, in alternative embodiments, macrocells 110 may operate in accordance with other standards and / or protocols, including Global System for Mobile communications (GSM). The macrocells 110 shown in FIG. 1 correspond to different sectors associated with the BTS 105. For example, the BTS 105 may include three antennas (or three groups of antennas) that provide wireless connectivity to three sectors associated with three macrocells 110. However, those skilled in the art having the benefit of this disclosure should appreciate that alternative embodiments may use different BTS 105 to provide wireless connectivity for each macrocell 110. In addition, the wireless communication system 100 may include any number of macrocells 110 and / or BTSs 105. In alternative embodiments, the BTSs 105 may be part of a hierarchical or distributed network.

The wireless communication system 100 also includes an overlay network of femtocells 115. For example, femtocells 115 may be installed in businesses and / or homes by individual users, companies or other entities. For clarity, only four femtocells 115 are shown in FIG. 1. However, those skilled in the art having the benefit of this disclosure should appreciate that the wireless communication system 100 may include any number of femtocells 115 distributed throughout the wireless communication system 100. Femtocells 115 operate according to a different radio access technology than macrocells 110. In the illustrated embodiment, femtocells 115 operate in accordance with third generation standards and / or protocols. However, in alternative embodiments, femtocells 115 may operate in accordance with other standards and / or protocols different from the standards and / or protocols used to implement macrocells 110. .

The wireless communication system 100 is a mobile shown in FIG. 1 configured to communicate over an air interface using standards and / or protocols implemented in both macrocells 110 and femtocells 115. User equipment, such as unit 120. Thus, mobile unit 120 may be associated with one or more femtocells 115. For example, a user having a femtocell 115 (1) installed in a house may configure the mobile unit 120 to recognize the femtocell 115 (1) as its first femtocell. Thus, when the mobile unit 120 approaches the first femtocell 115 (1), the mobile unit 120 may preferentially handoff to the first femtocell 115 (1). In one embodiment, femtocell 115 (1) may be part of a femtocell cluster (not shown in FIG. 1). However, in cases where femtocell 115 (1) and macrocell 110 (3) implement different radio access technologies, from BTS 105 providing connectivity to macrocell 110 (3). Handover between radio access technologies (RATs) should be used to hand off to femtocell 115 (1).

Femtocell 115 (1) is the first femtocell for mobile unit 120. As used herein, the term “premier femtocell” refers to a femtocell associated with mobile unit 120, such that mobile unit 120 is authorized to preferentially access the first femtocell. Exemplary situations in which a first femtocell may be defined include femtocells installed by users in their homes, femtocells (or clusters of femtocells) installed where a business is located, and the like. Mobility information associated with the first femtocell 115 (1) may be communicated with network entities such as mobile unit 120 and base station 105 and / or base station controller 105 (not shown in FIG. 1). Not stored). Exemplary mobility information includes information identifying the first femtocell 115 (1), information indicating the location of the first femtocell 115 (1), and the radio access technology implemented by the first femtocell 115 (1). Information indicating, but not limited to, information indicating a frequency (or frequencies) used by the first femtocell 115 (1) for communication over the air interface, and the like.

In the illustrated embodiment, mobile unit 120 has an existing wireless communication link 125 with base station transceiver 105. For example, mobile unit 120 may utilize macrocell 110 (3) via one or more antennas supported by base station transceiver 105 using link 125 established in accordance with 2G CDMA standards and / or protocols. Can communicate with)). The mobile unit 120 can then determine the distance 130 between the mobile unit 120 and its first femtocell 115 (1). For example, the mobile unit 120 can compare its location with the location of the first femtocell 115 (1) to determine the distance 130. If the distance 120 is less than the selected distance threshold, the mobile unit 120 generates an inter-RAT event and sends a message to the base station 105 containing the inter-RAT event to the femtocell 115 (1). It may indicate that a location-based threshold for handoff has been reached. In embodiments that support inter-RAT channel quality measurements, mobile unit 120 may also use a channel, for example, using pilot channels transmitted by base station 105 and / or femtocell 115 (1). Quality or signal strength quality measurements can be made.

The wireless communication system 100 then initiates an inter-RAT handoff of the mobile unit 120 from the 2G base station transceiver 105 and the corresponding macrocell 110 (3) to the 3G femtocell 115 (1). Can be. A wireless communication link 135 between the mobile unit 120 and the first femtocell 115 (1) may be created (using appropriate standards and / or protocols) and the mobile unit 120 may be (dashed line 140). May be handed off to the first femtocell 115 (1). In one embodiment, the wireless communication system 100 may also use other criteria such as measurements of the quality of the wireless communication link 135 to determine when to perform a location-based inter-RAT handoff. In the illustrated embodiment, the location-based inter-RAT handoff applies only to the first femtocells 115 (1) associated with the mobile unit 120. Thus, the air interface 125 for the macrocell 110 (3) may provide channel conditions of sufficiently high quality or better channel conditions than those supported by the different air interface 135. Although may be, mobile unit 120 may preferentially be handed off to its first femtocell 115 (1).

2 conceptually illustrates a second exemplary embodiment of a wireless communication system 200. In the illustrated embodiment, the wireless communication system 200 includes a 3G femtocell 205, a mobile unit 210, a 2G base station transceiver 215, and a 2G base station controller (BSC) 220. Those skilled in the art having the benefit of this disclosure should appreciate that a wireless communication system may include other elements that are not shown in FIG. 2 to avoid unnecessarily obscure discussion. Femtocell 205 is a first femtocell for mobile unit 210 and operates in accordance with a first set of standards and / or protocols, such as a third generation femtocell standard for distributed architecture. In the illustrated embodiment, femtocell 205 stores information 225 including a femtocell identifier and information indicating the location of femtocell 205. Location information may be determined using a number of different techniques including global positioning system (GPS) functionality integrated into femtocell 205 or manual configuration of femtocell 205 by a user or service provider. Base station transceiver 215 operates according to a second set of standards and / or protocols that are different from the first set of standards and / or protocols. For example, base station transceiver 215 may operate according to a second generation standard.

Mobile unit 210 is configured to recognize femtocell 205 as its first femtocell. In the illustrated embodiment, the mobile unit 210 stores the identity of the femtocell 205, the location of the first femtocell 205, and any other mobility parameters associated with the first femtocell 205. Exemplary mobility parameters include primary scrambling codes (PSC), international mobile subscriber identity (IMSI), mobile identifier number (MIN), UTRAN radio network temporary identifier (U-RNTI, UTRAN Radio Network) Temporary Identifier) and the like, but is not limited thereto. In the illustrated embodiment, mobile unit 210 defines a local variable, eg, data structure 230, for storing femtocell information related to mobility. In the illustrated embodiment, the mobile unit 210, when the PremierFemtoCellAvailable Boolean value of the setup message from the femtocell 205 is set to TRUE (relative to mobility), the current cell information and the femtocell (in the connection setup message) Location information (which may be provided by 205) is stored in the PremierFemtoCell local data structure 230.

The base station controller 220 stores a context database associated with the mobile unit 210 as well as other user equipment and / or mobile units served by macrocells connected to the base station controller 220. Maintain 235. In the illustrated embodiment, base station controller 220 stores information associated with mobile unit 210 and information indicating that mobile unit 210 is associated with a first femtocell in context 235 for mobile unit 210. do. For example, context 235 for mobile unit 210 may include an identifier, a Boolean variable indicating that the first femtocell is available, a parameter indicating a frequency used by the first femtocell 205, and a femtocell 205 of the femtocell 205. May include a location. Once the context 235 for the mobile unit 210 is configured, the base station controller 220 knows that the mobile unit 210 is associated with the first femtocell. Although mobile unit 210 is shown as being associated with a single first femtocell, those skilled in the art having the benefit of this disclosure would appreciate that mobile unit 210 may be associated with one or more first femtocells in alternative embodiments. You have to be aware.

In the illustrated embodiment, mobile unit 210 is initially a base station transceiver via a wireless communication link that includes uplink 240 and downlink 245 established in accordance with a second set of standards and / or protocols. Served by 215. Mobile unit 210 also knows its location. In the illustrated embodiment, mobile unit 210 determines its location using signals 255 provided by a network of global positioning system (GPS) satellites 260 (only one is shown in FIG. 2). GPS functionality 250 is included. Alternatively, mobile unit 210 may be aware of its location using information provided by base station transceiver 215 via downlink 245. This approach may be referred to as secondary-GPS technology. Thus, the mobile unit 210 can use the stored location of the first femtocell 205 to determine how far the first femtocell 205 is from the mobile unit 210.

Base station controller 220 can configure mobile unit 210 to trigger on an event basis. In one embodiment, base station controller 220 may define a location-based inter-RAT event that may be used to trigger an inter-RAT handoff from base station transceiver 215 to first femtocell 205. For example, the mobile unit 210 can be configured to transmit a message that includes an event between location-based RATs when the distance between the first femtocell 205 and the mobile unit 210 is below a configured threshold distance. . The threshold distance may be in any one of a variety of ways, including pre-configuration of the threshold distance (eg, based on the size of the building served by the first femtocell 205), user configuration of the threshold distance, and the like. Can be configured.

Base station controller 220 may also use other information, such as channel conditions, if available, to determine whether to perform inter-RAT handoff of mobile unit 210 to femtocell 205. For example, if the radio access technologies implement techniques for performing channel condition measurements on the target access technology in an inter-RAT handover, the channel conditions can be measured and the values of the measured channel conditions can be measured by the base station controller 220. May be reported to the base station controller 220 in response to the requests provided by the. For example, in the case of a location-based inter-RAT handover event, the base station controller 220 causes the mobile unit 210 to receive an inter-RAT event message from the mobile unit 210. You can command to make and report channel condition measurements. One example of a technique used in UMTS techniques is a compression mode technique that enables mobile units to perform channel condition or signal strength quality measurements during certain time intervals. However, other radio access technologies, such as 2G CDMA, may not implement techniques for performing channel condition or signal strength quality measurements on the target access technology in inter-RAT handover. For example, some radio access technologies implement blind handovers for inter-RAT handovers.

3 conceptually illustrates a first exemplary embodiment of a method 300 of handing off a mobile unit (MU) from a macrocell (BTS / BSC) to a first femtocell (PFC) using event-based triggering. . The macrocell and the first femtocell use different radio access technologies for communications over the air interface. Thus, the first exemplary embodiment illustrates an intersystem handoff procedure (eg, 2G CDMA for a 3G femtocell). First, a connection is established (at 305) between the mobile unit and the macrocell. The macrocell then determines (at 310) whether the mobile unit has an associated first femtocell. For example, the macrocell may examine the context associated with the mobile unit to determine (at 310) whether the variable PremierFemtoCellAvailable is set to true. In the illustrated embodiment, the mobile unit has an associated first femtocell, and therefore, the macrocell is also used by the first femtocell to communicate with the mobile unit, which is different from the radio technology of the macrocell in the illustrated embodiment. Determine the established wireless technology (at 310).

The macrocell then constructs (at 315) location-based inter-RAT events. The mobile unit receives this information to configure (at 320) an event between location-based RATs. The mobile unit may also store parameters related to the location-based inter-RAT event, including thresholds for location-based handoff, thresholds for channel quality required for handoff (if this information is available), etc. At 320). A call and / or session may then be established (at 325) between the mobile unit and the macrocell. At this point in the processing (indicated by dashed line 330), the call or session between the mobile unit and the macrocell may continue. However, the mobile unit continuously compares its location with the location of its first femtocell, and continuously monitors the signal strength qualities associated with the air interface to the femtocell in systems implementing techniques that allow inter-RAT signal strength quality measurements. do.

The mobile unit determines (at 335) whether the distance between the mobile unit and the first femtocell is below a threshold. For example, the mobile unit can compare (at 335) its current location with the location of the first femtocell stored in the mobile unit's memory to determine the distance:

UE_PremierFemto_distance = UE_coordinates-premierFemto_coordinates

This distance can then be compared to a threshold and the handoff procedure can be triggered if:

UE_PremierFemto_distance <MacroToFemtoDistanceThreshold

When the distance criterion is met, the mobile unit sends 340 an event-based measurement report that includes information indicating that a location-based event for intersystem handoff has been generated. In one embodiment, the base station controller (BSC) uses the location-based event included in the event-based measurement report to trigger (at 360) inter-RAT handover of the mobile unit from the macrocell to the femtocell. For example, the base station controller (BSC) can send (at 365) a request to initiate an inter-RAT handover for the mobile unit. The mobile unit may then execute an inter-RAT handover from the macrocell to the first femtocell (at 370).

As discussed herein, different radio access technologies may or may not support signal strength quality measurements between RATs. If the radio access techniques involved in the handover shown in FIG. 3 support inter-RAT channel or signal strength quality measurements, the information collected using these measurements may perform inter-RAT handover from the macrocell to the first femtocell. It can be used to determine (at 370). The method 300 may then include the additional steps illustrated by box 343. In the illustrated embodiment, the macrocell responds (at 345) to the event-based measurement report by sending a message indicating that the mobile unit should make measurements of signal strength quality between the mobile unit and the first femtocell. One example technique for enabling a mobile unit to perform inter-RAT signal strength quality measurements is the compression mode implemented in UTMS systems. However, other techniques may also be used to support measurement of signal strength quality between the mobile unit and the first femtocell.

When the mobile unit receives this message, the mobile unit measures (at 350) the signal strength quality using, for example, a pilot channel transmitted by the femtocell. Information indicative of the measured signal strength quality may then be reported (at 355) to the base station controller. Inter-RAT measurements can be reported periodically or based on certain configured events. If the mobile periodically reports the results of the inter-RAT measurements (at 355), the base station controller (BSC) is able to support the mobile unit via the air interface to provide communication that the distance-based criterion is still met (i.e. UE_PremierFemto_distance <MacroToFemtoDistanceThreshold). When the signal strength quality of the channel between the femtocell and the femtocell is high enough, the information included in the measurement reports can be used to trigger (at 360) inter-RAT handover of the mobile unit from the macrocell to the femtocell. If the mobile unit transmits event-based inter-RAT measurement reports, the mobile unit can determine when the signal strength quality of the channel between the mobile unit and the femtocell is high enough to support communication over the air interface. In various alternative embodiments, the measurement report may also include, but is not limited to, other mobility information including primary scrambling codes, timing and / or offset information, measurements of signal strength quality, and the like. .

Some and corresponding detailed descriptions of the disclosed subject matter are presented in terms of algorithms and symbolic representations of operations on data bits in software, or computer memory. These descriptions and representations are those by which those skilled in the art effectively convey the substance of their work to others skilled in the art. As used herein and in general terms, an algorithm is considered to be a consistent sequence of steps leading to a desired result. The steps require physical manipulations of physical quantities. In general, although not required, these quantities take the form of optical, electrical or magnetic signals that can be stored, transmitted, combined, compared and otherwise manipulated. It has sometimes proved to be convenient for referencing these signals, such as bits, values, elements, symbols, characters, terms, numbers, etc., mainly for common use.

However, it should be noted that both of these and similar terms are convenience labels associated with the appropriate physical quantities and only apply to these quantities. Unless specifically stated otherwise or apparent from the discussion, "processing" or "computing" or "calculating" or "determining" or "displaying" Terms such as and the like manipulate data represented as physical electromagnetic quantities in registers and memories of a computer system, and similarly as physical quantities within computer system memories or registers or other such information storage, transmission or display devices. It relates to the operations and processes of a computer system or similar electronic computing device that converts to other data represented.

Moreover, aspects of the software implementation of the disclosed subject matter are generally encoded on some form of program storage medium or implemented over some type of transmission medium. The program storage medium may be magnetic (eg, floppy disk or hard drive) or optical (eg, compact disc read-only memory, or “CD ROM”), and may be read only or random access. Similarly, the transmission medium may be twisted pair, coaxial cable, optical fiber or some other suitable transmission medium known in the art. The disclosed subject matter is not limited by these aspects of any given implementation.

The specific embodiments disclosed above are illustrative only, as the disclosed subject matter may be modified and practiced in different but equivalent ways to those skilled in the art having the benefit of the teachings herein. Moreover, it is not limited to the details of construction or design herein shown, except as described in the following claims. Thus, it is apparent that the specific embodiments disclosed above may be changed or modified, and all such modifications are considered to be within the scope of the disclosed subject matter. Accordingly, protection pursued herein is as set forth in the following claims.

100, 200: wireless communication system 105: base station transceiver
110: macrocells 115: femtocells
120, 210: mobile unit 205: 3G femtocell
215: 2G base station transceiver 220: 2G base station controller
260: GPS satellites

Claims (10)

An implementation method in a mobile unit configured to communicate with a wireless communication system comprising at least one base station transceiver and at least one femtocell, the at least one base station transceiver being in communication with the at least one femtocell. In a method of implementation in the mobile unit using different radio access technologies:
Determining, at the mobile unit, a distance between the mobile unit and the at least one femtocell;
When the distance between the mobile unit and the at least one femtocell is less than a threshold distance, sending a first measurement report from the mobile unit to the at least one base station transceiver, wherein the first measurement report reports a first event. Transmitting the first measurement report; And
When the distance between the mobile unit and the at least one femtocell is less than a threshold distance, performing handoff between radio access technologies from the at least one base station transceiver to the at least one femtocell. How to implement in units. The method of claim 1,
In the mobile unit, using the information generated at the base station controller and configuring the first event provided to the mobile unit by the at least one base station transceiver, wherein the first event is generated from the at least one macrocell. Configuring the first event, associated with a handoff between radio access technologies to at least one femtocell,
And transmitting the first measurement report comprises transmitting a request to activate a measurement between a first measurement report comprising a first event and a radio access technology. The method of claim 2,
Measuring signal strength quality of a pilot channel transmitted by the at least one femtocell, and performing handoff between the radio access technologies when the signal strength quality exceeds a selected threshold; And
Transmitting a second measurement report when the signal strength quality exceeds a selected threshold, wherein the second measurement report includes a primary scrambling code, timing information, offset information, pilot channel signal-to-noise ratio; Or transmitting at least one of the received signal channel power of a pilot channel. The method of claim 1,
And periodically transmitting second measurement reports comprising at least one of a primary scrambling code, timing information, offset information, pilot channel signal-to-noise ratio, or received signal channel power of the pilot channel. How to implement in The method of claim 1,
Identifying the at least one femtocell as at least one first femtocell associated with the mobile unit,
Identifying the at least one femtocell as at least one first femtocell:
Providing a call connection request from the mobile unit to the at least one femtocell;
In the mobile unit, in response to providing the call connection request, information indicating the location of the at least one femtocell from the at least one femtocell and information indicating that the at least one femtocell is a first femtocell associated with the mobile unit; Receiving; And
Storing information indicative of the location of the first femtocell in the mobile unit. An implementation method in a base station controller configured to be deployed in a wireless communication system comprising at least one base station transceiver and at least one femtocell, wherein the at least one base station transceiver uses a different radio access technology than the at least one femtocell. In the implementation method in the base station controller:
When the distance between the mobile unit and the at least one femtocell is less than a threshold distance, receiving a first measurement report from the mobile unit, wherein the first measurement report comprises a first event. Receiving step; And
When the at least one femtocell is less than the threshold distance, performing handoff between radio access technologies of the mobile unit from the at least one base station transceiver to the at least one femtocell. . The method according to claim 6,
Generating, at the base station controller, a first event associated with a handoff between radio access technologies from the at least one base station transceiver to the at least one femtocell; And
Providing the first event to the mobile unit via the at least one base station transceiver,
Receiving the first measurement report comprises receiving a request to activate a measurement between a first measurement report that includes the first event and a radio access technology. The method according to claim 6,
Receiving at least one second measurement report comprising information indicative of measurement results of signal strength quality of a pilot channel transmitted by the at least one femtocell,
And executing the inter-radio access technology handoff comprises executing the inter-radio access technology handoff when the signal strength quality exceeds a selected threshold. The method of claim 8,
Receiving the at least one second measurement report when the signal strength quality exceeds the selected threshold, wherein the second measurement report comprises a primary scrambling code, timing information, offset information, pilot channel signal-to-noise ratio Or receiving at least one of the received signal channel power of a pilot channel; And
At least one of periodically receiving second measurement reports comprising at least one of a primary scrambling code, timing information, offset information, pilot channel signal-to-noise ratio, or received signal channel power of the pilot channel. Comprising a base station controller. The method according to claim 6,
Identifying the at least one femtocell as at least one first femtocell associated with the mobile unit.

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