HK1180162B - Method for determining a base station to hand over a cellular device to - Google Patents

Abstract

The present invention is directed to a method for determining a base station to hand over a cellular device to. Embodiments of this disclosure include methods in which a core network controller determines which femtocell base station to handover a cellular device to. Methods include comparing a cell parameter difference provided by a base station with a cell parameter difference provided by the cellular device. The cell parameter difference provided by the base station is the cell parameter difference between the base station and each neighboring base station. The cell parameter difference provided by the cellular device is the cell parameter difference between the base station through which the cellular device is currently associated with to the core network and each neighboring base station. The core network controller compares the cell parameter difference provided by the cellular device with the cell parameter difference provided by the base station. The core network hands the cellular device to the base station when the cell parameter difference provided by each are substantially equivalent.

Description

Method for determining base station for handover of cellular device

Reference to related applications

The benefit of U.S. provisional patent application No. 61/548,662 filed on 18/10/2011 and U.S. patent application No. 13/491,646 filed on 8/6/2012, the entire contents of which are incorporated herein by reference, are claimed.

Technical Field

The present disclosure relates generally to cellular networks, and more particularly to handing over cellular devices from one cell (cell) member to another cell member.

Background

The demand for wireless data consumption has increased exponentially, and an outdoor sparsely placed macro base station is no longer able to provide sufficient wireless service coverage to meet the demand for increased wireless data. The number of smart phones, smart tablets, and laptops accessing social networks, online games, streaming online video, and other traditional personal computing applications now available on cellular devices has placed significant pressure on the traditional wireless infrastructure supported by macro base stations. It is often not feasible to add more macro base stations to the wireless infrastructure to meet the demand for wireless data consumption. Macro base stations are too expensive and require a large amount of outdoor space that is not normally available, especially in cities. There is a need for smaller and more cost effective cellular base stations for wireless infrastructure.

Femto cells are supported by small, short-range, indoor access points for homes or small offices. The femto cell enabled access point acts as a relay for the macro base station. The femtocell enabled access point maintains a femtocell continuous wireless connection for the cellular device as the cellular device leaves the coverage area of the first macro base station and enters the coverage area of a neighboring macro base station. Femto cell enabled access points maintain continuous wireless connectivity via handovers from macro base stations and/or from other femto cells. Handover is the process by which a cellular device hands over between different base stations during a network connection, which connection is not interrupted during handover.

Typically, the core network includes various combinations of macro cells and femto cells. The core network identifies the various access points supporting the macro and femto cells using various identifiers. Often, these different network identifiers are not unique. Conversely, in some cases, the same identifier may be used to identify more than one access point. As a result, the core network cannot uniquely identify the access point. This is particularly troublesome when performing handover in the core network. A large number of femtocells deployed in the same area may obscure the core network involving a certain femtocell, and a handover should be performed for a cellular device leaving the coverage area of a neighboring macro base station and/or femtocell. This ambiguity may cause the core network to perform handover for the cellular device to a femtocell for which the cellular device is not within its coverage. This may cause the cellular device to disconnect from the wireless network and the wireless service to be interrupted.

Disclosure of Invention

One aspect of the present invention relates to a core network controller, comprising: a processor configured to: receiving a cellular device cell parameter difference provided by a cellular device located within a macro cell, wherein the cellular device cell parameter difference is a cell parameter difference between a macro base station and a neighboring base station, receiving femtocell access point cell parameter differences provided by respective femtocell access points, wherein the femtocell access point cell parameter differences are cell parameter differences between respective femtocell access points and the macro base station, comparing the cellular device cell parameter differences to respective femtocell cell parameter differences, thereby determining the femtocell cell parameter difference substantially equal to the cellular device cell parameter difference, and performing a handover procedure to the femtocell access point for the cellular device located within the macrocell, the femtocell access point providing a femtocell cell parameter difference substantially equal to the cellular device cell parameter difference; and a memory configured to store cell parameter data provided by the processor.

In the above core network controller, preferably, the cellular device cell parameter difference is a difference between a frame start of the macro base station and a frame start of the neighboring femtocell access point.

In the above core network controller, preferably, the cellular device cell parameter difference is a difference between a System Frame Number (SFN) of the macro base station and an SFN of the neighboring femtocell access point.

In the above core network controller, preferably, the respective femtocell access point cell parameter differences are differences in frame start between the respective femtocell access points and the macro base station.

In the above core network controller, it is preferable that the difference between the respective femtocell access points is a difference between an SFN of the respective femtocell access point and the SFN of the macro base station.

In the above core network controller, preferably the processor is further configured to request the first femtocell access point to adjust a start of frame of the first femtocell access point such that the start of frame of the first femtocell access point is different from a start of frame of the second femtocell access point.

In the above core network controller, preferably the processor is further configured to request the first femtocell access point to adjust the frame start of the first femtocell access point when the first femtocell access point provides to the processor a first femtocell access point cell parameter difference substantially equal to a second femtocell access point cell parameter difference provided to the processor by the second femtocell access point.

Another aspect of the invention relates to a femtocell access point, comprising: a sniffer configured to: measuring a base station cell parameter difference between a femtocell access point and respective neighboring base stations, and providing wireless service to a cellular device that has entered a femtocell supported by the femtocell access point based on a handover procedure performed by a core network controller for the cellular device from a neighboring base station to the femtocell access point, wherein the handover procedure is based on the base station cell parameter difference, the base station cell parameter difference being substantially equal to a cellular device cell parameter difference between the neighboring base station and the femtocell access point; and a cellular transceiver configured to transmit and receive cellular signals for the cellular devices that have entered the femtocell supported by the femtocell access point.

In the above-described femtocell access point, it is preferable that the cellular device cell parameter difference is a difference between a frame start of the neighboring base station and a frame start of the femtocell access point.

In the above-described femtocell access point, it is preferable that the cellular device cell parameter difference is a difference between a System Frame Number (SFN) of the neighboring base station and an SFN of the femtocell access point.

In the above-described femtocell access point, it is preferable that the base station cell parameter difference is a difference in frame start between the femtocell access point and each of neighboring base stations.

In the above-described femtocell access point, it is preferable that the base station cell parameter difference is a difference between SFNs of respective neighboring base stations and the femtocell access point.

In the above-described femtocell access point, it is preferable that the femtocell access point further includes: a local oscillation controller configured to adjust a start of frame of the femtocell access point such that the start of frame of the femtocell access point is different from the start of frame of respective neighboring femtocell access points.

In the above-described femtocell access point, it is preferred that the local oscillator is further configured to adjust the start of frame of the femtocell access point when the base station cell parameter difference provided by the femtocell access point is substantially equal to a second base station cell parameter difference provided by the neighbouring femtocell access point.

Yet another aspect of the present invention relates to a method for determining a base station for handover of a cellular device, comprising: requesting, by a core network controller, an identification of each base station from a plurality of base stations; identifying, by the core network controller, an ambiguity between a first base station and a second base station each having a substantially similar identification; providing, by the cellular device, a cellular device cell parameter difference, wherein the cellular device cell parameter difference is a cell parameter difference between an original base station including an original cell in which the cellular device is located and a neighboring base station; providing a base station cell parameter difference by each base station, wherein the base station cell parameter difference is a cell parameter difference between each base station and the original base station; comparing, by the core network controller, each base station cell parameter difference to the cellular device cell parameter difference; and performing, by the core network controller, a handover procedure for the cellular device from the original base station to a base station having a base station cell parameter difference substantially equal to the cellular device cell parameter difference.

In the above method, preferably, the cell parameter difference of the cellular device is a difference between frame starts of each base station and the original base station.

In the above method, it is preferable that the cell parameter difference of each base station is a difference between System Frame Numbers (SFNs) of each base station and the original base station.

In the above method, it is preferable that the method further comprises: the method includes requesting a first base station to adjust a frame start of the first base station such that the frame start of the first base station is different from a frame start of a second base station.

In the above method, it is preferable that the method further comprises: requesting the first base station to adjust a start of frame of the first base station when the first base station provides a first base station cell parameter difference that is substantially equal to a second base station cell parameter difference provided by the second base station.

In the above method, preferably, the core network periodically requests the cell parameter difference from the cellular device and the base station cell parameter difference from each base station.

Drawings

Embodiments of the present disclosure are described with reference to the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements. Additionally, the left-most digit(s) of a reference number is the figure in which the reference number first appears.

Fig. 1 illustrates an exemplary cellular network in accordance with an embodiment of the present disclosure;

fig. 2A illustrates a second exemplary cellular network according to an embodiment of the present disclosure;

fig. 2B illustrates a third exemplary cellular network according to an embodiment of the present disclosure;

fig. 3 illustrates a block diagram of an example femtocell access point that may be used in a cellular network, according to an example embodiment of the present disclosure;

fig. 4 is a block diagram of an example core network controller in accordance with an embodiment of the present disclosure; and

fig. 5 is a flowchart of exemplary operational steps of a core network according to an exemplary embodiment of the present disclosure.

The present disclosure is now described with reference to the drawings. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the reference number.

Detailed Description

The following detailed description refers to the accompanying drawings that illustrate exemplary embodiments consistent with this disclosure. References in the detailed description to "one exemplary embodiment," "an exemplary embodiment example," etc., indicate that a particular feature, structure, or characteristic may be included, but not all exemplary embodiments necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same exemplary embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an exemplary embodiment, it is within the knowledge of one skilled in the relevant art to affect such feature, structure, or characteristic in connection with other exemplary embodiments whether or not explicitly described.

The exemplary embodiments described herein are provided for illustrative purposes and are not limiting. Other exemplary embodiments are possible, and modifications to the exemplary embodiments may be made within the spirit and scope of the present disclosure. Therefore, the detailed description is not meant to limit the disclosure. Rather, the scope of the disclosure is defined only by the following claims and their equivalents.

Embodiments of the present disclosure may be implemented in hardware, firmware, software, or any combination thereof. Embodiments of the disclosure may also be implemented as instructions stored on a machine-readable medium, which may be read and executed by one or more processors. A machine-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computing device). For example, a machine-readable medium may include Read Only Memory (ROM); random Access Memory (RAM); a magnetic disk storage medium; an optical storage medium; a flash memory device; electrical, optical, acoustical or other form of propagated signals (e.g., carrier waves, infrared signals, digital signals, etc.), and other media. To perform certain actions, firmware, software, routines, instructions may be further described herein. However, it should be appreciated that such descriptions are merely convenient and that such behavior is actually due to a computing device, processor, controller, or other device executing the firmware, software, routines, instructions, etc.

For purposes of discussion, each of the various components discussed may be considered a module, and the term "module" is understood to include at least one of software, firmware, and hardware (e.g., one or more circuits, microchips or devices, or any combination thereof), and any combination thereof. In addition, it is understood that each module may include one or more components within an actual device, and that each component forming a portion of the described module may operate in cooperation, or independently, of any other component forming a portion of the module. Thus, the various modules described herein may represent separate modules within an actual device. Further, the components within a module may be in a single device or distributed among multiple devices in a wired or wireless manner.

The following detailed description of exemplary embodiments will so fully reveal the general nature of the disclosure that others can, by applying knowledge within the skill of the relevant art, readily modify and/or adapt for various applications such exemplary embodiments, without undue experimentation, without departing from the spirit and scope of the present disclosure. Accordingly, such adaptations and modifications are intended to be within the meaning and range of equivalents of the exemplary embodiments, based on the teaching and guidance presented herein. It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings herein.

SUMMARY

The cellular network may include various cell members, such as one or more macrocells, one or more microcells, such as one or more picocells or one or more femtocells, to provide some examples, or any combination thereof. The cellular network identifies these different cell members using various network identifiers. Often, these different network identifiers are not unique. Rather, in some cases, the same network identifier may be used to identify multiple cell members. As a result, the core network cannot uniquely identify the cell members. In these cases, the cellular network may request that various cell members share the same network identifier, thereby providing cell parameters for identification purposes. The cellular network may evaluate the cell parameters to uniquely identify various cell parameters that share the same network identifier.

Exemplary cellular network

Fig. 1 illustrates an exemplary cellular network in accordance with an embodiment of the present disclosure. Core network 100 represents a wireless communication network that supports wireless voice or data communication between cellular devices. Core network 100 may provide wireless connectivity to cellular devices through one or more transceivers, referred to as cell sites. The cell sites are connected to a cellular telephone switch that is connected to a public telephone network or to another cellular telephone switch within the core network 100.

The core network 100 comprises subnetworks 102.1 to 102. N. Each of the subnetworks 102.1 to 102.N may include one or more macro base stations, femtocell access points, cellular devices, or any combination of macro base stations, femtocell access points, and cellular devices; however the configuration and arrangement and number of these devices may vary between subnets.

The subnet 102.1 includes macro base stations 104, femto cells 106.1 to 106.k, and cellular devices 110.1 to 110. m. The femtocells 106.1 to 106.k include corresponding ones of the femtocell access points 108.1 to 108. d. In some cases, the femto cells 106.1 to 106.k may further include one or more of the cellular devices 110.1 to 110. m. For example, the femto cell 106.k comprises a cellular device 110.2. Cellular devices 110.1 through 110.m may represent smart phones, smart tablets, mobile phones, portable computing devices, other computing devices such as personal computers, laptop computers, or desktop computers, computer peripherals such as printers, portable audio and/or video players, and/or any other suitable electronic devices that will be apparent to persons skilled in the relevant art without departing from the spirit and scope of the present disclosure.

The subnetworks 102.1 to 102.N may be coupled to each other via a backhaul connection 150, thereby forming the core network 100. Backhaul connection 150 may include, but is not limited to, a copper twisted wire pair connection, a T-1/E-1 connection, a Digital Subscriber Line (DSL) connection, a fiber optic connection, a coaxial cable connection, and/or any other type of connection capable of supporting data communication as recognized by one skilled in the relevant art without departing from the scope of the present disclosure. Although not shown in fig. 1, subnets 102.1 through 102.N may couple a Public Switched Telephone Network (PSTN), an Internet Protocol (IP) network, the internet, an intranet, and/or any other type of communications network recognized by one of ordinary skill in the relevant art via backhaul connection 150.

The sub-network 102.1 provides wireless services to the cellular devices 110.1 to 110.m via the macro base station 104. The macro base station 104 may be coupled to other subnets originating from the subnets 102.1 to 102.N via a backhaul connection 150. The macro base station 104 may be a long range cellular base station that is used to provide wireless service covering a large surface area, often referred to as a macrocell. The macro base station 104 may provide wireless services based on cellular standards including, but not limited to: transitional standard 95 (IS-95), Code Division Multiple Access (CDMA), global system for mobile communications (GSM), Time Division Multiple Access (TDMA), General Packet Radio Service (GPRS), enhanced data rates for GSM evolution (EDGE), UMTS, Wideband Code Division Multiple Access (WCDMA), Time Division Synchronous Code Division Multiple Access (TDSCDMA), Orthogonal Frequency Division Multiplexing (OFDM), High Speed Downlink Packet Access (HSDPA), and/or any other suitable cellular standard that will be apparent to persons skilled in the relevant art(s) without departing from the spirit and scope of the present disclosure.

The femtocells 106.1 to 106.k and the cellular device 110.1 are within the coverage area of the macro base station 104, i.e. within a macro cell. The femtocells 106.1 to 106.k comprise corresponding femtocell access points 108.1 to 108. d. Generally, the femtocell access points 108.1 to 108.d provide a smaller footprint, often referred to as a femtocell, for wireless services within a macrocell. The femtocell access points 108.1 to 108.d can provide wireless services based on cellular standards including, but not limited to, IS-95, CDMA, GSM, TDMA, GPRS, EDGE, UMTS, WCDMA, TDSCDMA, OFDM, and HSDPA, and/or any other suitable cellular standard apparent to those skilled in the relevant art without departing from the spirit and scope of the present disclosure.

The cellular devices 110.1 to 110.m may receive wireless traffic from the macro base station 104 and/or the femtocell access points 108.1 to 108. d. For example, in some cases, the cellular devices 110.1 to 110.m may have wireless data consumption requirements that may not be solely supported by the macro base station 104. The wireless data consumption requirements of cellular devices 110.1 through 110.m may include, but are not limited to, services involving computing capabilities such as Short Message Service (SMS), email, internet access, gaming, short-range wireless communications, video camera, Multimedia Messaging Service (MMS) messaging, digital audio player, radio, Global Positioning System (GPS) services, access to social networks, online gaming, streaming online video, and other conventional personal computing applications now available on cellular devices, and/or any other suitable service apparent to those skilled in the relevant art without departing from the spirit and scope of the present disclosure.

Typically, the sub-network 102.1 provides a continuous or near continuous wireless connection for the cellular devices 110.1 to 110.m using the macro base station 104 and/or the femtocell access points 108.1 to 108. d. As cellular devices 110.1 to 110.m move or roam throughout the coverage area of sub-network 102.1, sub-network 102.1 hands over these cellular devices between the various macro base stations and/or access points, thereby maintaining a continuous or near-continuous wireless connection. Typically, a handover procedure is performed within the subnet 102.1 when one of the cellular devices 110.1 to 110.m associates with one of the femtocell access points 108.1 to 108.d and re-associates with another femtocell access point 108.1 to 108. d. The hand-in procedure is performed within the sub-network 102.1 when one of the cellular devices 110.1 to 110.m is associated with the macro base station 104 and re-associated with one of the femtocell access points 108.1 to 108. d. When one of the cellular devices 110.1 to 110.m associates with one of the femtocell access points 108.1 to 108.d and re-associates with the macro base station 104, a hand-out hand-in procedure is performed within the subnet 102.1.

Subnet 102.1 performs these different handover procedures via the control channel. The control channels represent the center channels used to control the macro base station 104 and/or the femtocell access points 108.1 to 108. d. The control channels may include, but are not limited to, a Broadcast Control Channel (BCCH), a Frequency Control Channel (FCCH), a Synchronization Channel (SCH), a Common Control Channel (CCCH), a Random Access Channel (RACH), a Paging Channel (PCH), an access grant control channel (AGCH), a Cell Broadcast Channel (CBCH), a Dedicated Control Channel (DCCH), a stand-alone dedicated control channel (SDCCH), an Associated Control Channel (ACCH), a Slow Associated Control Channel (SACCH), a Fast Associated Control Channel (FACCH), and/or any other suitable control channel apparent to one skilled in the relevant art without departing from the spirit and scope of the present disclosure.

During execution of the handover procedure, sub-network 102.1 identifies the femto cell access points 108.1 to 108.d with which the cellular devices 110.1 to 110.m reassociate. The femtocell access points 108.1 to 108.d are configured with network identifiers to allow the sub-network 102.1 for identification purposes. For example, the network identifier may include a Primary Scrambling Code (PSC). PSC denotes a scrambling code used by the femtocell access points 108.1 to 108.d when communicating using a control channel. Often, the network identifier is not unique. Rather, in some cases, the same network identifier may be used to identify multiple ones of the access points 108.1 to 108. d. As a result, subnet 102.1 cannot uniquely identify access points 108.1 through 108. d. Second and third exemplary cellular networks

Fig. 2A and 2B each illustrate an exemplary cellular network in accordance with an embodiment of the present disclosure. In those situations where the network identifier is not unique, the core networks 200 and 250 use various cell parameters for identification purposes. The core networks 200 and 250 may evaluate cell parameters to uniquely identify various cell members sharing the same network identifier. The core networks 200 and 250 include a core network controller 202, a macrocell 208, a first femtocell 204, and a second femtocell 206. The macro cell 208 includes a macro base station 212 and a cellular device 210. The first femtocell 204 includes a femtocell access point 214. The second femtocell 206 comprises a femtocell access point 216. Core networks 200 and 250 share many similar features with core network 100; therefore, only the differences between core networks 200 and 250 and core network 100 are discussed in further detail.

As mentioned above, each femtocell access point 214 and 216 can assign an identification code, e.g., a PSC, from the core network controller 202 to provide an example. In some instances, multiple femtocell access points 214 and 216 can allocate substantially similar PSCs. When identifying these access points with substantially similar PSCs, the assignment of substantially similar PSCs to femtocell access points 214 and 216 can cause ambiguity to the core network controller 202.

To overcome the ambiguity, the core network controller 202 uniquely determines to identify those access points with substantially similar PSCs based on the cell parameters. For example, if the femtocell access points 214 and 216 have substantially similar PSCs, the cellular device 210 and the femtocell access points 214 and 216 may provide cell parameters to the core network controller 202. The core network controller 202 can examine each cell parameter to determine which of the cell parameters provided by the femtocell access points 214 and 216 can be approximately equal to the cell parameters provided by the cellular device 210 to uniquely identify the femtocell access points 214 and 216. The cell parameters provided by the cellular device 210 and the femtocell access points 214 and 216 may include cell parameters that reflect an observed time difference pointer between the macro base station 212 and each of the femtocell access points 214 and 216. The observed time difference pointer may also include the difference in frame start between the macro base station 212 and the femtocell access points 214 and 216. The difference in frame start of the cellular device 210 and the femtocell access points 214 and 216 may be measured by measuring the difference in a combination of Connection Frame Number (CFN), SFN, and CFN, and/or any other suitable method of distinguishing measurable cell parameters between base stations and cellular devices that will be apparent to persons skilled in the relevant art without departing from the spirit and scope of the present disclosure. The observed time difference indicator may further include a difference in System Frame Number (SFN) between macro base station 212 and femtocell access points 214 and 216.

In an example, the cellular device 210 is within a macro cell 208 supported by a macro base station 212. The cellular device 210 is connected to the core network 200 via the macro base station 212 and receives wireless traffic therefrom. A cellular device 210 may leave a macro cell 210 supported by a macro base station 212 and enter a femtocell 204 supported by a femtocell access point 214. However, when femtocell access points 214 and 216 include substantially similar PSCs, ambiguity is caused to the core network controller 202 determining whether to handover the cellular device 210 to the femtocell 204 or the femtocell 206.

To overcome the ambiguity, the core network controller 202 requests the cellular device 210 and the femtocell access points 214 and 216 to provide SFN measurements. Macro base station 212 may be characterized as a SFN with SFN0, and femtocell access points 214 and 216 may be characterized as SFNs with SFN1 and SFN2, respectively. Cellular device 210 provides SFN difference between SFN of macro base station 212 (i.e., SFN 0) and SFN of femtocell access point 214 (i.e., SFN 1) [ SFN 0-SFN 1 ]. Femtocell access point 214 provides a SFN difference between the SFN of femtocell access point 214 (i.e., SFN 1) and the SFN of macro base station 212 (i.e., SFN 0) [ SFN 1-SFN 0 ]. Femtocell access point 216 provides an SFN difference | SFN 2-SFN 0| between the SFN of femtocell access point 216 (i.e., SFN 2) and the SFN of the macrocell (i.e., SFN 0).

Core network controller 202 compares | SFN 0-SFN 1| provided by cellular device 210 with | SFN 1-SFN 0| provided by femtocell access point 214 and | SFN 2-SFN 0| provided by femtocell access point 216. The core network controller 202 determines that | SFN 0-SFN 1| provided by the cellular device 210 and | SFN 1-SFN 0| provided by the femtocell access point 214 are substantially equal, thereby uniquely identifying the handover of the cellular device 210 to the femtocell access point 214.

In some cases, as illustrated in fig. 2B, the core network controller 202 still cannot distinguish between femtocells when the femtocell access points provide a difference of SFNs that are substantially equal to each other. For example, if macro base station 212 may be characterized as a SFN with SFN0, and both femtocell access points 214 and 216 may be characterized as SFNs with SFN 1. Femtocell access point 214 can have a timestamp that represents a start of frame that is substantially equal to a frame of femtocell access point 216. The difference | SFN 1-SFN 0| between femtocell access point 214 and macro base station 212 (SFN 0) may be substantially equal to the difference | SFN 1-SFN 0| between femtocell access point 216 and macro base station 212. To further distinguish between femtocell access points having substantially similar PSCs and substantially equal timestamps indicating frame starts, core network controller 202 can send a time shift request requesting that one of femtocell access points 214 and 216 perform a time shift in its frame start. The core network controller 202 can request the femtocell access points to perform a time shift in their frame start that can be sufficient for the core network controller 202 to distinguish the difference in SFN provided by each of the femtocell access points 214 and 216. The core network controller 202 can then appropriately determine which femtocell 204 and 206 to handover the cellular device 210 to based on the difference in SFN provided by each femtocell access point 214 and 216 and the cellular device 210.

Third exemplary cellular network

Fig. 3 illustrates a block diagram of an example femtocell that may be used in a core network according to an example embodiment of the present disclosure. The femtocell access point 300 includes a sniffer 308, and the sniffer 308 measures the difference in SFN between the femtocell access point 300 and each neighboring base station to the femtocell access point 300 and provides the difference in SFN to the core network. The femtocell access point 300 also includes a local oscillation controller 316. The local oscillation controller 316 adjusts the frame start of the femtocell access point 300 upon request by the core network 300, and thus the time difference between the femtocell access point 300 and each neighboring base station may be different. The femtocell access point 300 comprises an antenna 302, a cellular transceiver 304, a broadband transceiver 306, a sniffer 308, an identification provider 310, a code base 312, a local oscillation controller 316 and a local oscillator. Femtocell access point 300 shares many similar features with femtocell access points 108.1 to 108.d and femtocell access points 214 and 216; thus, only the differences between the femtocell access point 300 and the femtocell access points 108.1 to 108.d and the femtocell access points 214 and 216 are discussed in further detail.

The antenna 302 captures received voice or data communications from one or more fixed location transceivers and/or provides transmitted voice or data communications from the cellular transceiver 304 to one or more fixed location transceivers.

Cellular transceiver 304 may include one or more amplifiers, such as, for example, one or more Low Noise Amplifiers (LNAs) and/or one or more low noise block converters (LNBs), to amplify received voice or data communications after they are captured by antenna 302 and/or to amplify transmitted voice or data communications before they are provided to one or more fixed location transceivers, as some examples. The cellular transceiver 304 may additionally include one or more filters to filter received voice or data communications and/or transmitted voice or data communications, respectively. Cellular transceiver 304 may further include one or more mixers to down-convert received voice or data communications captured by antenna 302 and/or to up-convert transmitted voice or data communications before being provided to one or more fixed location transceivers. The cellular transceiver 304 may further include a duplexer or switch to separate received voice or data communications captured from the one or more fixed location transceivers from transmitted voice or data communications provided to the one or more fixed location transceivers.

The wideband transceiver 306 may include one or more amplifiers, such as one or more Low Noise Amplifiers (LNAs) and/or one or more low noise block converters (LNBs) to provide some examples to amplify the received wideband data 354. The wideband transceiver 306 may additionally include one or more filters to filter received wideband data 354 and/or transmitted wideband data 352, respectively. Cellular transceiver 304 may further include one or more mixers to down-convert received wideband data 354 and/or up-convert transmitted wideband data 352. The wideband transceiver 306 may further include a duplexer or switch to separate received wideband data 354 from transmitted wideband data 352. Received broadband data 354 and/or transmitted broadband data 352 may be received and/or transmitted via twisted copper pairs, T-1/E-1 lines, DSL, fiber optics, coaxial cable, and/or any other type of connection capable of supporting data communication as recognized by one skilled in the relevant art without departing from the scope of the present disclosure.

A sniffer (sniffer) 308 may perform a sniffing procedure in which the sniffer 308 retrieves an identification code from the core network controller. For example, the sniffer may retrieve the PSC from the core network controller. The sniffer 308 may request PSC from the core network controller via PSC data 376. The broadband transceiver 306 can up-convert the PSC data 376 to transmitted broadband data 352 and transmit the PSC data 376 to the core network controller. The core network controller may provide the PSC to the femtocell access point 300 via the received broadband data 354. The broadband transceiver can down-convert the received broadband data 354 to provide the PSC374 to the sniffer 308. The sniffer can store the PSC364 in the code repository 312.

The core network controller may request PSCs from the femtocell access point 300. After downconverting such requests in the received broadband data 354, the broadband transceiver 306 can send the request for the PSC via the PSC 374. Sniffer 308 can retrieve PSC364 from code repository 312. Sniffer 308 can provide PSC data 376 to broadband transceiver 306. The broadband transceiver 306 can up-convert the PSC data 376 to transmitted broadband data 352 to provide the transmitted broadband data 352 to the core network.

As mentioned above, the core network controller may request cell parameters from the femtocell access point 300. Upon down-converting such a request in the received broadband data 354, the broadband transceiver 306 can send a request to the sniffer 308 for the base station cell parameters 356. The sniffer can perform a sniffing procedure in which sniffer 308 retrieves base station cell parameters 356 from each neighboring macro cell and/or femto cell. The base station cell parameters 356 may be provided by the broadband transceiver 306 to the sniffers via broadband data 354 received from each neighboring macro base station and/or femtocell access point. In an example, sniffer 308 can retrieve SFN information from each neighboring macro base station and/or femtocell access point via base station cell parameters 356. Sniffer 308 may compare retrieved base station cell parameters 356 with femto cell data. For example, sniffer 308 can determine a difference in SFN between neighboring macrocell base stations and/or femtocell access points and SFN of femtocell access point 300. Sniffer 308 may then provide base station cell parameter difference 358 to broadband transceiver 306. The wideband transceiver 306 may up-convert the base station cell parameter difference 358 into the transmitted wideband data 352 and provide the transmitted wideband data 352 to the core network.

If the core network controller hands over the cellular device to the femtocell access point 300, the sniffer may activate 350 the cellular transceiver 304 with the cellular device activation. Once the cellular transceiver 304 receives the cellular device activation 350, the cellular transceiver operates as mentioned above.

As mentioned above, the femtocell access point 300 may provide the cell identification 362 and the base station cell parameter difference 358 to the core network controller. The cell identification is an identification of the femtocell access point 300. The cell identification 362 may be stored in the identification provider 310. Sniffer 308 can provide cell identification 360 to broadband transceiver 306. The broadband transceiver 306 may up-convert the cell identification 360 into transmitted broadband data 352 and provide the transmitted broadband data 352 to the core network controller.

As mentioned above, the sniffer 308 may provide the base station cell parameter differences 358, cell identifications 362 and/or PSC data 376 to the core network controller based on periodic requests for the base station cell parameter differences 358, cell identifications 360 and/or PSC data 376 from the core network controller. The sniffer 308 may also provide the base station cell parameter difference 358, cell identification 360 and/or PSC data 376 to the core network controller on a periodic basis without a request from the core network controller.

As mentioned above, the core network controller may request the femtocell access point 300 to adjust its start of frame. The wideband transceiver 306 may down-convert the received wideband data 354 to obtain a start of frame adjustment request 368. The local oscillator controller 316 adjusts the start of frame of the local oscillator 318 with the start of frame control signal 370 based on the start of frame adjustment request 368. The local oscillator controller 316 adjusts the start of frame control signal 370 so that the local oscillator 318 sufficiently adjusts the start of frame for the femtocell access point 300 so that the core network can distinguish the femtocell access point 300 from other femtocells. The local oscillator 318 provides the adjusted start of frame 372 to the sniffer 308. Sniffer 308 can determine the difference in SFN between femtocell access point 300 and other nearby base stations based on the adjusted frame start 372. The sniffer can provide the SFN adjusted in the base station cell parameter difference 358 to the broadband transceiver 306. The broadband transceiver may up-convert the adjusted SFN provided by base station cell parameter difference 358 to transmitted broadband data 352 and provide the transmitted broadband data 352 to the core network controller.

Exemplary core network controller

Fig. 4 shows a block diagram of a core network controller according to an example embodiment of the present disclosure. The core network controller 400 includes a processor 402 and a memory 404. The core network controller 400 shares many similar features with the core network controller 202; therefore only the differences between the core network controller 202 and the core network controller 400 will be discussed in further detail.

As mentioned above with respect to the core network controller 202, the core network controller 400 may receive the cell parameter 450.1 from a cellular telephone attempting to move from the first cell to the second cell. The network controller 400 may also receive cell parameters 450.2 through 450.N from neighboring base stations and/or access points. The processor 402 may store the stored cell parameters 456 in the memory 404.

As mentioned above, the processor 402 may determine the cell to which to handover the cellular device based on the cell parameters 450.1 to 450. N. The processor 402 may perform the handover procedure with the handover program signal 452. The processor 402 may also request the access point to shift its start of frame with a start of frame shift request 454.

Exemplary operational control flow for core networks

Fig. 5 is a flowchart of exemplary operational steps of a core network according to an exemplary embodiment of the present disclosure. The present disclosure is not limited to this operational description. Rather, other operational control flows from the teachings herein that are apparent to those of ordinary skill in the relevant art are within the scope and spirit of the present disclosure. The following discussion describes the steps in fig. 5.

At step 510, the operational control flow requests identification of each base station from a plurality of base stations.

At step 520, the operational control flow identifies ambiguities between the first base station and the second base station that each have a substantially similar identification. If the identification of the first femtocell access point is substantially similar to the identification of the second femtocell access point, then the operational control flow proceeds to provide a cell parameter difference. If the identification of the first femtocell access point is not substantially similar to the identification of the second femtocell access point, then the operational control flow proceeds to perform a handover procedure. For example, the operational control flow identifies whether the PSC of a first femtocell access point, such as the femtocell access point 214 providing an example, is substantially similar to the PSC of a second femtocell access point, such as the femtocell access point 216 providing an example. If the PSC of femtocell access point 214 is substantially similar to the PSC of femtocell access point 216, then a cell parameter difference is required and the operational control flow proceeds to step 530. If the PSC of femtocell access point 214 is not substantially similar to the PSC of femtocell access point 216, then no cell parameter difference is needed and the operational control flow proceeds to step 560.

At step 530, the operational control flow provides a cellular device cell parameter difference, wherein the cellular device cell parameter difference is a cell parameter difference between an original base station including an original cell in which the cellular device is located and a neighboring base station. Specifically, a cellular device, such as cellular device 210, provides a cellular device cell parameter difference, such as SFN 0-SFN 1, which provides an example, where SFN 0-SFN 1 is a cell parameter difference between an original base station, such as macro base station 212, which provides an example, and a neighboring base station, such as femtocell access point 214, which provides an example, macro base station 212 includes macro cell 208, which provides an example, in which original cell, such as cellular device 210, is located.

At step 540, the operational control flow provides a base station cell parameter difference, wherein the base station cell parameter difference is a cell parameter difference between each base station and the original base station. Specifically, a base station, such as femtocell access point 214, providing an example base station cell parameter difference between itself and an original base station, such as macro base station 212, providing an example | SFN 1-SFN 0 |.

At step 550, the operational control flow compares each base station cell parameter difference to the cellular device cell parameter difference. Specifically, each base station cell parameter difference, e.g., providing example | SFN 2-SFN 0| is compared to a cellular device cell parameter difference, e.g., providing example | SFN 0-SFN 1 |.

At step 560, the operational control flow performs a handover procedure for the cellular device from the original base station to a base station having a base station cell parameter difference substantially equal to the cellular device cell parameter difference. Specifically, a handoff procedure is performed for a cellular device, such as the example cellular device 210, from an original base station, such as the example macro base station 212, to a base station, such as the example femtocell access point 214, having a base station cell parameter difference, such as the example | SFN 1-SFN 0|, that is substantially equal to a cellular device cell parameter difference, such as the example | SFN 0-SFN 1 |.

Conclusion

It should be appreciated that the detailed description section, and not the abstract section, is intended to be used to interpret the claims. The abstract section may set forth one or more, but not all exemplary embodiments of the disclosure, and thus, is not intended to limit the disclosure and the appended claims in any way.

The present disclosure has been described with the aid of functional building blocks illustrating the implementation of specific functions and relationships thereof. The boundaries of these functional building blocks have been arbitrarily defined herein for the convenience of the description. Other boundaries may be defined so long as the specified functions and relationships thereof are appropriately performed.

It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the disclosure. Thus, the present disclosure should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

Claims (8)

1. A core network controller, the core network controller comprising:

a processor configured to:

receiving a cellular device cell parameter difference provided by a cellular device located within a macro cell, wherein the cellular device cell parameter difference is a cell parameter difference between a macro base station and a neighboring base station,

receiving femtocell access point cell parameter differences provided by respective femtocell access points, wherein the femtocell access point cell parameter differences are cell parameter differences between respective femtocell access points and the macro base station,

comparing the cellular device cell parameter difference to respective femtocell cell parameter differences to determine the femtocell cell parameter difference substantially equal to the cellular device cell parameter difference, an

Performing a handover procedure for the cellular device located within the macro cell to the femtocell access point, the femtocell access point providing a femtocell cell parameter difference substantially equal to the cellular device cell parameter difference; and a memory configured to store cell parameter data provided by the processor,

wherein each femtocell access point cell parameter difference is a difference in frame start between each femtocell access point and the macro base station, and

wherein the processor is further configured to request a first femtocell access point to adjust a frame start of the first femtocell access point such that the frame start of the first femtocell access point is different from a frame start of a second femtocell access point.

2. The core network controller of claim 1, wherein the cellular device cell parameter difference is a difference of a start of frame of the macro base station and a start of frame of the neighboring femtocell access point.

3. The core network controller of claim 2, wherein the cellular device cell parameter difference is a difference of a System Frame Number (SFN) of the macro base station and a SFN of the neighboring femtocell access point.

4. The core network controller of claim 1, wherein each femtocell access point difference is a difference of an SFN of each femtocell access point and the SFN of the macro base station.

5. The core network controller of claim 1, wherein the processor is further configured to request the first femtocell access point to adjust a start of frame of the first femtocell access point when the first femtocell access point provides to the processor a first femtocell access point cell parameter difference that is substantially equal to a second femtocell access point cell parameter difference provided to the processor by the second femtocell access point.

6. A femtocell access point, comprising:

a sniffer configured to:

measuring a difference in cell parameters of the base station between the femtocell access point and each of the neighboring base stations, an

Providing wireless service to a cellular device that has entered a femtocell supported by a femtocell access point based on a handover procedure performed by a core network controller to the cellular device from a neighboring base station to the femtocell access point, wherein the handover procedure is based on the base station cell parameter difference, which is substantially equal to a cellular device cell parameter difference between the neighboring base station and the femtocell access point, wherein the cellular device cell parameter difference is a difference of a frame start of the neighboring base station and a frame start of the femtocell access point, and the base station cell parameter difference is a difference of frame starts between the femtocell access point and respective neighboring base stations;

a cellular transceiver configured to transmit and receive cellular signals for the cellular devices that have entered the femtocell supported by the femtocell access point; and

a local oscillation controller configured to adjust a start of frame of the femtocell access point such that the start of frame of the femtocell access point is different from the start of frame of respective neighboring femtocell access points.

7. A method for determining a base station for cellular device handover, comprising:

requesting, by a core network controller, an identification of each base station from a plurality of base stations;

identifying, by the core network controller, an ambiguity between a first base station and a second base station each having a substantially similar identification;

providing, by the cellular device, a cellular device cell parameter difference, wherein the cellular device cell parameter difference is a cell parameter difference between an original base station including an original cell in which the cellular device is located and a neighboring base station, wherein the cellular device cell parameter difference is a difference in frame start of the respective base station and the original base station;

providing a base station cell parameter difference by each base station, wherein the base station cell parameter difference is a cell parameter difference between each base station and the original base station;

comparing, by the core network controller, each base station cell parameter difference to the cellular device cell parameter difference;

performing, by the core network controller, a handover procedure for the cellular device from the original base station to a base station having a base station cell parameter difference substantially equal to the cellular device cell parameter difference; and

requesting the first base station to adjust a start of frame of the first base station such that the start of frame of the first base station is different from the start of frame of the second base station.

8. The method of claim 7, wherein the core network periodically requests the cell device cell parameter difference from the cell device and the base station cell parameter difference from respective base stations.