Patent Publication Number: US-2013237233-A1

Title: Method and apparatus for offloading devices in femtocell coverage

Description:
CLAIM OF PRIORITY UNDER 35 U.S.C. §119 
     The present Application for Patent claims priority to Provisional Application No. 61/608,559 entitled “METHOD AND APPARATUS FOR OFFLOADING DEVICES IN FEMTOCELL COVERAGE” filed Mar. 8, 2012, and assigned to the assignee hereof and hereby expressly incorporated by reference herein. 
    
    
     BACKGROUND 
     The disclosed aspects relate generally to communications between and/or within devices and specifically to methods and systems for device offload from a femto node. 
     Wireless communication systems are widely deployed to provide various types of communication content such as, for example, voice, data, and so on. Typical wireless communication systems may be multiple-access systems capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, . . . ). Examples of such multiple-access systems may include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and the like. Additionally, the systems can conform to specifications such as third generation partnership project (3GPP), 3GPP long term evolution (LTE), ultra mobile broadband (UMB), evolution data optimized (EV-DO), etc. 
     Generally, wireless multiple-access communication systems may simultaneously support communication for multiple mobile devices. Each mobile device may communicate with one or more base stations via transmissions on forward and reverse links. The forward link (or downlink) refers to the communication link from base stations to mobile devices, and the reverse link (or uplink) refers to the communication link from mobile devices to base stations. Further, communications between mobile devices and base stations may be established via single-input single-output (SISO) systems, multiple-input single-output (MISO) systems, multiple-input multiple-output (MIMO) systems, and so forth. In addition, mobile devices can communicate with other mobile devices (and/or base stations with other base stations) in peer-to-peer wireless network configurations. 
     To supplement conventional base stations, additional low power base stations can be deployed to provide more robust wireless coverage to mobile devices. For example, low power base stations (e.g., which can be commonly referred to as Home NodeBs or Home eNBs, collectively referred to as H(e)NBs, femto nodes, femtocell nodes, pico nodes, micro nodes, etc.) can be deployed for incremental capacity growth, richer user experience, in-building or other specific geographic coverage, and/or the like. In some configurations, such low power base stations are connected to the Internet via broadband connection (e.g., digital subscriber line (DSL) router, cable or other modem, etc.), which can provide the backhaul link to the mobile operator&#39;s network. In this regard, low power base stations are often deployed in homes, offices, etc. without consideration of a current network environment. 
     Thus, improved apparatus and methods for determining whether and/or when to offload a device from a femto node may be desired. 
     SUMMARY 
     The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later. 
     In accordance with one or more aspects and corresponding disclosure thereof, various aspects are described in connection with determining whether to offload a device from a femto node. In one example, a serving node is equipped to obtain load information regarding a target node, compare an expected throughput at the target node, estimated based in part on the load information, to a threshold, and determining whether to handover a device to the target node based in part on the comparing. In an aspect, the serving node is further equipped to compute its own throughput based on parameters specific to the serving femto node or the device, and the threshold is the throughput at the serving femto node. 
     According to related aspects, a method for determining whether to offload a device from a femto node is provided. The method can include obtaining load information regarding a target node. Further, the method can include comparing an expected throughput at the target node, estimated based in part on the load information, to a threshold. Moreover, the method may include determining whether to handover a device to the target node based in part on the comparing. 
     Another aspect relates to a communications apparatus enabled to determine whether to offload a device from a femto node. The communications apparatus can include means for means for obtaining load information regarding a target node. Further, the communications apparatus can include means for means for comparing an expected throughput of the target node, estimated based in part on the load information, to a threshold. Moreover, the communications apparatus can include means for means for determining whether to handover a device to the target node based in part on the comparing. 
     Another aspect relates to a communications apparatus. The apparatus can include a processing system configured to obtain load information regarding a target node. Further, the processing system may be configured to compare an expected throughput of the target node, estimated based in part on the load information, to a threshold. Moreover, the processing system may further be configured to determine whether to handover a device to the target node based in part on the comparing. 
     Still another aspect relates to a computer program product, which can have a computer-readable medium including code for obtaining load information regarding a target node. Further, the computer-readable medium may include code for comparing an expected throughput of the target node, estimated based in part on the load information, to a threshold. Moreover, the computer-readable medium can include code for determining whether to handover a device to the target node based in part the on the comparing. 
     To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed, and this description is intended to include all such aspects and their equivalents. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosed aspects will hereinafter be described in conjunction with the appended drawings, provided to illustrate and not to limit the disclosed aspects, wherein like designations denote like elements, and in which: 
         FIG. 1  is a block diagram of an example system that facilitates offloading devices to or from a femto node. 
         FIG. 2  is a block diagram of an example system that facilitates handing over devices based on determining load information for one or more target nodes. 
         FIG. 3  is an illustration of an example wireless network environment that can be employed in conjunction with the various systems and methods described herein. 
         FIG. 4  is a flow chart of an aspect of an example methodology for determining whether to handover a device based on load information of a target node. 
         FIG. 5  is a conceptual data flow diagram illustrating the data flow between different modules/means/components in an exemplary apparatus. 
         FIG. 6  is a diagram illustrating an example of a hardware implementation for an apparatus employing a processing system 
         FIG. 7  is a block diagram of an example wireless communication system in accordance with various aspects set forth herein. 
         FIG. 8  illustrates an example wireless communication system, configured to support a number of devices, in which the aspects herein can be implemented. 
         FIG. 9  is an illustration of an exemplary communication system to enable deployment of femtocells within a network environment. 
         FIG. 10  illustrates an example of a coverage map having several defined tracking areas. 
     
    
    
     DETAILED DESCRIPTION 
     Various aspects are now described with reference to the drawings. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more aspects. It may be evident, however, that such aspect(s) may be practiced without these specific details. 
     As described further herein, low power base stations, such as femto nodes, can determine load at other base stations for offloading one or more devices thereto. In one example, determining the load can include measuring a downlink quality and comparing the downlink quality to one or more previous downlink quality measurements. For instance, a history of downlink quality for a base station can be determined such that comparing a current downlink quality to the history can indicate a load (or conversely a capacity) at the base station. In this regard, a potential throughput can additionally or alternatively be estimated based on the downlink quality comparison. The low power base station can compare the estimated load or throughput measurement to its own load, throughput, etc., and can accordingly determine whether to handover a device served by the lower power base station to the other base station. This can be based on other considerations as well. Such considerations can include handover considerations, such as whether the device reports signal quality for the other base station that at least achieves a threshold quality and/or a threshold difference to a quality reported for the low power base station. The considerations can additionally or alternatively include other information, such as a type of the other base station, an operating frequency thereof, a location of the device, an amount of resources of the lower power base station consumed by the device, and/or the like. 
     A low power base station, as referenced herein, can include a femto node, a pico node, micro node, home Node B or home evolved Node B (H(e)NB), relay, and/or other low power base stations, and can be referred to herein using one of these terms, though use of these terms is intended to generally encompass low power base stations. For example, a low power base station transmits at a relatively low power as compared to a macro base station associated with a wireless wide area network (WWAN). As such, the coverage area of the low power base station can be substantially smaller than the coverage area of a macro base station. 
     As used in this application, the terms “component,” “module,” “system” and the like are intended to include a computer-related entity, such as but not limited to hardware, firmware, a combination of hardware and software, software, or software in execution. For example, a component may be, but is not limited to being, a process running on a processor, a processor, an object, an executable, a thread of execution, a program, and/or a computer. By way of illustration, both an application running on a computing device and the computing device can be a component. One or more components can reside within a process and/or thread of execution and a component may be localized on one computer and/or distributed between two or more computers. In addition, these components can execute from various computer readable media having various data structures stored thereon. The components may communicate by way of local and/or remote processes such as in accordance with a signal having one or more data packets, such as data from one component interacting with another component in a local system, distributed system, and/or across a network such as the Internet with other systems by way of the signal. 
     Furthermore, various aspects are described herein in connection with a terminal, which can be a wired terminal or a wireless terminal. A terminal can also be called a system, device, subscriber unit, subscriber station, mobile station, mobile, mobile device, remote station, remote terminal, access terminal, user terminal, terminal, communication device, user agent, user device, or user equipment (UE). A wireless terminal or device may be a cellular telephone, a satellite phone, a cordless telephone, a Session Initiation Protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device having wireless connection capability, a tablet, a computing device, or other processing devices connected to a wireless modem. Moreover, various aspects are described herein in connection with a base station. A base station may be utilized for communicating with wireless terminal(s) and may also be referred to as an access point, a Node B, evolved Node B (eNB), home Node B (HNB) or home evolved Node B (HeNB), collectively referred to as H(e)NB, or some other terminology. 
     Moreover, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless specified otherwise, or clear from the context, the phrase “X employs A or B” is intended to mean any of the natural inclusive permutations. That is, the phrase “X employs A or B” is satisfied by any of the following instances: X employs A; X employs B; or X employs both A and B. In addition, the articles “a” and “an” as used in this application and the appended claims should generally be construed to mean “one or more” unless specified otherwise or clear from the context to be directed to a singular form. 
     The techniques described herein may be used for various wireless communication systems such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, WiFi carrier sense multiple access (CSMA), and other systems. The terms “system” and “network” are often used interchangeably. A CDMA system may implement a radio technology such as Universal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includes Wideband-CDMA (W-CDMA) and other variants of CDMA. Further, cdma2000 covers IS-2000, IS-95 and IS-856 standards. A TDMA system may implement a radio technology such as Global System for Mobile Communications (GSM). An OFDMA system may implement a radio technology such as Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM®, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS). 3GPP Long Term Evolution (LTE) is a release of UMTS that uses E-UTRA, which employs OFDMA on the downlink and SC-FDMA on the uplink. UTRA, E-UTRA, UMTS, LTE and GSM are described in documents from an organization named “3rd Generation Partnership Project” (3GPP). Additionally, cdma2000 and UMB are described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2). Further, such wireless communication systems may additionally include peer-to-peer (e.g., mobile-to-mobile) ad hoc network systems often using unpaired unlicensed spectrums, 802.xx wireless LAN, BLUETOOTH and any other short- or long- range, wireless communication techniques. 
     Various aspects or features will be presented in terms of systems that may include a number of devices, components, modules, and the like. It is to be understood and appreciated that the various systems may include additional devices, components, modules, etc. and/or may not include all of the devices, components, modules etc. discussed in connection with the figures. A combination of these approaches may also be used. 
     Referring to  FIG. 1 , an example wireless communication system  100  is illustrated that facilitates offloading devices to/from one or more nodes. System  100  comprises a macro node  102 , which can be a macro base station or a femto, pico, or other low power base station node, in one example. System  100  also includes femto nodes  104  and  106 , which can be substantially any type of low power base station or at least a portion thereof. The nodes  102 ,  104 , and  106  provide respective coverage areas  108 ,  110 , and  112 . System  100  also includes a plurality of devices  114 ,  116 ,  118 ,  120 ,  122 ,  124 ,  126 , and  128  that communicate with the nodes  102 ,  104 , or  106  to receive wireless network access. 
     As described, the femto nodes  104  and  106  can communicate with the wireless network (not shown) over a broadband connection. In addition, femto nodes  104  and  106  can communicate with one another, and/or with macro node  102 , over a backhaul connection. For example, upon initialization, one or more of the femto nodes  104  and/or  106  can also communicate with one another to form a grouping (e.g., an ad-hoc network). This allows the femto nodes  104  and/or  106  to communicate to determine parameters related to serving the various devices connected thereto (e.g., resource allocations, interference management, and/or the like), in one example. Moreover, femto nodes  104  and  106  can automatically configure themselves to operate in the wireless network (e.g., set transmit power, network identifiers, pilot signal resources, and/or the like based on similar information received over a backhaul connection, over-the-air, or otherwise sensed from surrounding nodes). In this example, the femto nodes  104  and  106  can behave as plug-and-play devices requiring little user interaction to be provisioned on the wireless network. 
     In an example, femto node  104  can operate in an open or hybrid access mode to offload device  124  from macro node  102 , though device  124  may not be a member of a CSG associated with femto node  104 , since device  124  is in range of femto node  104 . In some examples, however, though device  124  may be nearer to femto node  104 , femto node  104  may not be the best candidate for serving device  124 . For example, macro node  102  and/or femto node  106  may have more desirable characteristics. In one example, femto node  104  may have a greater downlink and/or uplink load than macro node  102  and/or femto node  106 , and thus handover to another node may result in better performance or improved experience for device  124 . 
     For example, femto node  104  can determine the downlink and/or uplink load of other nodes, and can determine an expected throughput based on the load and/or on the location of femto node  104  (e.g., or at least a device connected to femto node  104  from which measurement reports are received. In one example, the location can be determined as a function of pathloss with respect to the cell (e.g., macro node  102  or femto node  106 ) for which the expected throughput is being evaluated. Femto node  104  can compare the expected throughput with a threshold throughput to determine whether to handover device  124  to one of the other nodes. In one example, the threshold throughput can be a throughput at femto node  104  (e.g., a throughput measured by femto node  104 , a specific throughput reported by or otherwise determined for device  124 , an average throughput of one or more devices, etc.). In a further example, the threshold can be a function of the femto node  104  or device  124  location with respect to the cell (e.g., macro node  102  or femto node  106 ) for which the threshold throughput is evaluated, where location can correspond to pathloss with respect to the cell. 
     In one specific example, femto node  104  can determine downlink quality of another node, such as macro node  102 , femto node  106 , and/or the like, and compare the downlink quality to one or more historical downlink quality measurements to determine whether the node is at an acceptable downlink load. For example, femto node  104  can measure the downlink quality using a network listening module (NLM), based on reports from one or more devices, and/or the like. The femto node  104  can use the measurements to estimate a downlink load (e.g., high quality indicates low load and vice versa). In this example, femto node  104  can accumulate measurements over a period of time to determine historical downlink quality values, such as an average downlink quality, a maximum downlink quality (e g., minimum load), a minimum downlink quality (e.g., maximum load), and/or the like. A given downlink quality measurement can be compared to the historical downlink quality values to determine a downlink load, and/or an acceptability thereof The femto node  104  may further determine whether to use or how to use the historical downlink quality values (e.g., by applying an offset dependent on pathloss to macro node  102 , femto node  106 , and/or the like). 
     For example, where a downlink quality measured of femto node  106  is within a threshold difference of the minimum downlink quality, this can indicate the femto node  106  is experiencing downlink load near a maximum load, and thus, femto node  104  may not handover device  124  to femto node  106  even as the device  124  moves closer to femto node  106 . Femto node  104  may instead determine to continue serving device  124  and/or handover device  124  to macro node  102  or another femto node. In one example, femto node  104  infers an expected throughput at femto node  106  based on the estimated downlink load, and determines the throughput experienced by device  124  at femto node  104  (or an expected throughput at another node) is better than the expected throughput at femto node  106 . 
     Similarly, where a downlink quality measured of femto node  106  is near an average downlink quality or within a threshold difference of the maximum downlink quality, this can indicate the femto node  106  is experiencing a low to average load, and femto node  104  can handover device  124  to femto node  106 . This can be based on other factors as well, such as determining an expected throughput at femto node  106  based on the load and comparing to a throughput at femto node  104 . In addition, in determining whether to handover device  124 , femto node  104  can analyze other considerations as well, as described, such as a signal quality of femto node  106  reported by device  124  in a measurement report, a location of device  124  relative to femto node  106  (and/or femto node  104 ), a number of resources utilized by the device  124  at femto node  104 , and/or the like. It is to be appreciated that an uplink load at the other nodes can be additionally or alternatively measured (e.g., based on an uplink signal strength experienced at the other nodes, which can be determined from an indication received in overhead messages or backhaul communications from the other nodes). In any case, by considering at least a load at a potential target femto node, user experience at devices can be improved as handover to nodes that are substantially loaded can be avoided. 
       FIG. 2  illustrates an example system  200  for offloading devices to/from femto nodes in a wireless network. System  200  comprises a femto node  202  that provides wireless network access to a device  204 , as described, as well as a femto node  206  that is near femto node  202 . Femto nodes  202  and  206  can participate in an ad-hoc network, as described, to manage access provided to one or more devices, such as device  204 . Thus, for example, femto node  202  can be similar to one of femto nodes  104  or  106 , and femto node  206  can be similar to another one of femto nodes  104  or  106 . In this example, femto nodes  202  and  206  can communicate over a backhaul. System  200  also includes an optional centralized entity  208  that can communicate with femto nodes  202  and  206  to provide information thereto. The centralized entity  208  can be a H(e)NB gateway, a H(e)NB management server, and/or the like. As described, device  204  can be similar to one of devices  114 ,  116 ,  118 ,  120 ,  122 ,  124 ,  126 , and/or  128 , and can be a UE, modem (or other tethered device), a portion thereof, etc. Moreover, an optional macro node  210  is provided from which device  204  can be handed over to femto node  202  and/or to which femto node  202  can handover device  204 . Macro node  210  can be similar to macro node  102 , in one example. 
     Femto node  202  can include a load determining component  212  for determining a load at one or more other nodes, a throughput comparing component  214  for comparing an expected throughput of the load to a throughput at femto node  202 , and a mobility component  216  for determining whether to modify one or more communication parameters of femto node  202 , which may cause handover of a device, based at least on the throughput comparison. Femto node  202  also optionally includes an NLM component  218  for receiving and measuring signals from the other nodes. 
     Centralized entity  208  can include a load information providing component  220  for determining and/or communicating load information of one or more nodes to one or more femto nodes for determining whether to offload devices. 
     According to an example, load determining component  212  can determine load information  222  for one or more nodes for deciding whether to handover device  204  to the one or more nodes. For example, load determining component  212  can determine load information  222  for femto node  206  and/or macro node  210 . In one example, femto node  202  can utilize NLM component  218  to measure parameters from the femto node  206  and/or macro node  210 . The parameters can include measuring a downlink quality, such as chip-level energy over interference (Ec/Io) on a pilot channel (e.g., common pilot channel (CPICH)), from which a downlink load can be estimated as load information  222 . It is to be appreciated, in an example, that load determining component  212  can receive such information from device  204  (e.g., in a measurement report). In another example, load determining component  212  can determine load information  222  to include an uplink load at femto node  206  and/or macro node  210 . The uplink load can be based on an uplink RSSI, which can be based on an uplink interference information element (IE) in an overhead system information block received from the femto node  206  and/or macro node  210 . For example, a higher UL interference level can correspond to higher uplink load. 
     In one example, load determining component  212  can estimate the downlink load from the downlink quality, for example, by comparing the downlink quality to a history of downlink quality values. For example, load determining component  212  can consider historical quality values, such as an average downlink quality, a maximum downlink quality, a minimum downlink quality, etc. determined over a period of time. Load determining component  212  can compare a current downlink quality measurement to the historical quality values to determine a downlink load as load information  222  at a given node. For instance, the downlink load can be a value expressed as compared to the maximum and/or minimum downlink quality (e.g., a difference relative of the measured downlink quality to the maximum and/or the minimum downlink quality, a percentage related to the measured downlink quality relative to a scaling of the maximum and minimum downlink quality, and/or the like). Moreover, the historical downlink quality values used for comparison can be modified based on time of day, day of week, whether the day is a holiday, etc. For example, the typical load may be substantially different at certain times of the day, days of the week, etc. 
     In other examples, load determining component  212  can determine load information as reported by femto node  206  and/or macro node  210 . For example, such reporting can occur in layer 2 or layer 3 information (e.g., in one or more system information blocks over a broadcast channel) from the nodes, or other higher layer information (e.g., over a network interface between nodes). Similarly, this information can be received by NLM component  218  and/or reported by one or more devices, such as device  204 . In yet another example, load determining component  212  can observe mobility operations to/from femto node  206  and/or macro node  210 , and can use this information (e.g., along with downlink quality or otherwise) to determine load information  222 . For example, load determining component  212  can keep track of handover to/from the femto node  206  and/or macro node  210  as a computed estimate of a number of devices served by the nodes, and can estimate the load, as load information  222 , based on the number of devices handed over thereto (and/or therefrom). 
     In addition, load information providing component  220  can collect load information from femto nodes  202  and  206 , and/or macro node  210 , and provide the load information to various nodes. In this example, femto node  202  can receive load information  222  from centralized entity  208 . For example, load information providing component  220  can obtain the load information for distributing to femto nodes as described with respect to load determining component  212 , and/or can receive the load information from load determining component  212  present in femto node  202  and/or other nodes. Furthermore, for example, load determining component  212  can additionally or alternatively acquire load information  222 , or quality values or other metrics from which load information  222  is computed, from other femto nodes, such as femto node  206 . 
     In one example, throughput comparing component  214  can determine an expected throughput  224  of a node, such as femto node  206 , based on the downlink and/or uplink load information  222 . For instance, the expected throughput  224  can be a function of the load information  222 , such as a relationship between a downlink quality and the historical downlink quality values. Throughput comparing component  214  can optionally determine a throughput  226  related to femto node  202 , or one or more related measurements, such as downlink quality, for comparing to expected throughput  224  or related values. In one example, throughput comparing component  214  can determine the throughput  226  based on femto node  202  specific parameters, such as a number of available channel elements, a rise over thermal, memory utilization, transmit power, a channel quality, etc., or parameters specific to one or more devices communicating with femto node  202  (e.g., device  204 ), such as a channel quality or throughput as reported by the device, a transmit power of the device, and/or the like. 
     In any case, throughput comparing component  214  can compare the expected throughput  224  of a node, such as femto node  206 , to a threshold, which can be the throughput  226  at femto node  202  or a fixed threshold, to determine whether femto node  206  should serve a device communicating with femto node  202 , such as device  204 . Mobility component  216  can take this comparison into account in determining whether to cause handover of the device  204  to femto node  206 . For example, mobility component  216  can consider other parameters as well, such as a signal strength or quality of femto node  206  as reported by device  204  (e.g., as compared to a similar reported metric of femto node  202  or otherwise). Moreover, for example, mobility component  216  can consider a number of resources of femto node  202  utilized by the device  204 , a location of the device  204  with respect to femto node  202 , whether the device  204  is ping-ponging between two nodes (e.g., handing over more than a threshold number of times within a time period), and/or the like in determining whether to handover device  204  to the femto node  206 . 
     In this regard, mobility component  216  can determine whether to handover device  204  to femto node  206  based on the above aspects. In other examples, however, mobility component  216  can determine to additionally or alternatively modify communication parameters of femto node  202  that may cause handover of device  204  and/or other devices. For example, the communication parameters can include a transmission power of femto node  202 , an operating frequency of femto node  202 , other mobility parameters, downlink beacon transmission parameters, a communication state of one or more devices (e.g., such as transitioning devices to a lower or higher grant state), and/or the like. For example, where femto node  202  determines that femto node  206  has a higher expected throughput  224 , mobility component  216  can adjust the foregoing parameters so devices prefer communication with femto node  206  over femto node  202 . 
     Referring to  FIG. 3 , an example methodology relating to offloading devices from a femto node is illustrated. While, for purposes of simplicity of explanation, methodologies are shown and described as a series of acts, it is to be understood and appreciated that the methodologies are not limited by the order of acts, as some acts may, in accordance with one or more embodiments, occur in different orders and/or concurrently with other acts from that shown and described herein. For example, it is to be appreciated that a methodology could alternatively be represented as a series of interrelated states or events, such as in a state diagram. Moreover, not all illustrated acts may be required to implement a methodology in accordance with one or more embodiments. 
       FIG. 3  shows an example wireless communication system  300 . The wireless communication system  300  depicts one base station  310 , which can include a femto node, and one mobile device  350  for sake of brevity. However, it is to be appreciated that system  300  can include more than one base station and/or more than one mobile device, wherein additional base stations and/or mobile devices can be substantially similar or different from example base station  310  and mobile device  350  described below. In addition, it is to be appreciated that base station  310  and/or mobile device  350  can employ the systems ( FIGS. 1 ,  2 ,  5 , and  7 ) and/or methods ( FIG. 4 ) described herein to facilitate wireless communication there between. For example, components or functions of the systems and/or methods described herein can be part of a memory  332  and/or  372  or processors  330  and/or  370  described below, and/or can be executed by processors  330  and/or  370  to perform the disclosed functions. 
     At base station  310 , traffic data for a number of data streams is provided from a data source  312  to a transmit (TX) data processor  314 . According to an example, each data stream can be transmitted over a respective antenna. TX data processor  314  formats, codes, and interleaves the traffic data stream based on a particular coding scheme selected for that data stream to provide coded data. 
     The coded data for each data stream can be multiplexed with pilot data using orthogonal frequency division multiplexing (OFDM) techniques. Additionally or alternatively, the pilot symbols can be frequency division multiplexed (FDM), time division multiplexed (TDM), or code division multiplexed (CDM). The pilot data is typically a known data pattern that is processed in a known manner and can be used at mobile device  350  to estimate channel response. The multiplexed pilot and coded data for each data stream can be modulated (e.g., symbol mapped) based on a particular modulation scheme (e.g., binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), M-phase-shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM), etc.) selected for that data stream to provide modulation symbols. The data rate, coding, and modulation for each data stream can be determined by instructions performed or provided by processor  330 . 
     The modulation symbols for the data streams can be provided to a TX MIMO processor  320 , which can further process the modulation symbols (e.g., for OFDM). TX MIMO processor  320  then provides N T  modulation symbol streams to N T  transmitters (TMTR)  322   a  through  322   t . In various embodiments, TX MIMO processor  320  applies beamforming weights to the symbols of the data streams and to the antenna from which the symbol is being transmitted. 
     Each transmitter  322  receives and processes a respective symbol stream to provide one or more analog signals, and further conditions (e.g., amplifies, filters, and upconverts) the analog signals to provide a modulated signal suitable for transmission over the MIMO channel. Further, N T  modulated signals from transmitters  322   a  through  322   t  are transmitted from N T  antennas  324   a  through  324   t , respectively. 
     At mobile device  350 , the transmitted modulated signals are received by N R  antennas  352   a  through  352   r  and the received signal from each antenna  352  is provided to a respective receiver (RCVR)  354   a  through  354   r . Each receiver  354  conditions (e.g., filters, amplifies, and downconverts) a respective signal, digitizes the conditioned signal to provide samples, and further processes the samples to provide a corresponding “received” symbol stream. 
     An RX data processor  360  can receive and process the N R  received symbol streams from N R  receivers  354  based on a particular receiver processing technique to provide N T  “detected” symbol streams. RX data processor  360  can demodulate, deinterleave, and decode each detected symbol stream to recover the traffic data for the data stream. The processing by RX data processor  360  is complementary to that performed by TX MIMO processor  320  and TX data processor  314  at base station  310 . 
     The reverse link message can comprise various types of information regarding the communication link and/or the received data stream. The reverse link message can be processed by a TX data processor  338 , which also receives traffic data for a number of data streams from a data source  336 , modulated by a modulator  380 , conditioned by transmitters  354   a  through  354   r , and transmitted back to base station  310 . 
     At base station  310 , the modulated signals from mobile device  350  are received by antennas  324 , conditioned by receivers  322 , demodulated by a demodulator  340 , and processed by a RX data processor  342  to extract the reverse link message transmitted by mobile device  350 . Further, processor  330  can process the extracted message to determine which precoding matrix to use for determining the beamforming weights. 
     Processors  330  and  370  can direct (e.g., control, coordinate, manage, etc.) operation at base station  310  and mobile device  350 , respectively. Respective processors  330  and  370  can be associated with memory  332  and  372  that store program codes and data. Processors  330  and  370  can also perform functionalities described herein to support offloading devices from a femto node. 
     Turning to  FIG. 4 , an example methodology  400  is displayed that facilitates determining whether to cause devices to handover from a femto node. 
     At  402 , load information regarding a target node can be obtained. For example, this can include measuring a downlink quality of the target node and comparing to historical downlink qualities of the target node, as described, to estimate a load on the node. In other examples, this can include determining the load information based on various factors, such as monitoring a number of reselections or handovers performed to and/or from the target node. In yet another example, this can include receiving the load information, or any of the above information from which the load information can be estimated, from the target node and/or from a centralized entity or other nodes. Moreover, as described, the load information can correspond to uplink load, and can be measured based on one or more uplink parameters (e.g., uplink RSSI at the target node). 
     At  404 , an expected throughput of the target node, estimated based in part on the load information, can be compared to a threshold. As described, the threshold can be a fixed threshold, a throughput at a serving femto node, etc. For example, the expected throughput can be estimated in relation to the load information, and can thus include an expected downlink and/or uplink throughput. Where the load information indicates the target node is at a threshold load, the expected throughput can be estimated at a lower value than where the load information indicates the target node load is below the threshold. For example, the relationship between the load and the expected throughput can correspond to a mapping of values based on previous reported throughputs for given loads, and/or the like. In any case, as described, the expected throughput can be compared to a threshold, which can include a fixed threshold or the throughput at the serving femto node computed based on parameters specific to the serving femto node and/or on parameters specific to devices communicating therewith. 
     At  406 , it can be determined whether to handover a device to the target node based in part on the comparing. For example, where the expected downlink or uplink throughput at the target node is better than the throughput measured at the serving femto node, handover can be preferred. In one example, additional parameters can be evaluated for determining whether to handover the device, such as a reported signal quality of the target node, a number of resources utilized by the device, etc. Moreover, determining whether to handover at  406  can comprise modifying mobility related parameters instead of or in addition to actually performing handover. For example, parameters can include a transmission power, an operating frequency, downlink beacon parameters, states of one or more devices, and/or the like. 
     It will be appreciated that, in accordance with one or more aspects described herein, inferences can be made regarding estimating a load at a femto node and/or a respective throughput, and/or the like, as described. As used herein, the term to “infer” or “inference” refers generally to the process of reasoning about or inferring states of the system, environment, and/or user from a set of observations as captured via events and/or data. Inference can be employed to identify a specific context or action, or can generate a probability distribution over states, for example. The inference can be probabilistic—that is, the computation of a probability distribution over states of interest based on a consideration of data and events. Inference can also refer to techniques employed for composing higher-level events from a set of events and/or data. Such inference results in the construction of new events or actions from a set of observed events and/or stored event data, whether or not the events are correlated in close temporal proximity, and whether the events and data come from one or several event and data sources. 
       FIG. 5  is a conceptual data flow diagram  500  illustrating the data flow between different modules/means/components in an example apparatus  502 . The apparatus may be a serving node. The apparatus includes a reception module  504 , a throughput comparison module  506 , a target node throughput estimation module  508 , a handover determination module  510 , a transmission module  512 , and a serving node throughput module  514 . 
     In an operational aspect, reception module  504  may obtain load information  520  regarding a target node  102 ,  106 . In an aspect, reception module  504  may obtain a downlink quality at the target node  102 ,  106 . In another aspect, reception module  504  may obtain load information  520  from measuring the downlink quality or the one or more historical downlink quality values of the target node. In such an aspect, the downlink quality and the one or more historical downlink quality values correspond to a chip-level energy over interference measurement of a pilot channel of the target node  102 ,  106 . In another aspect, reception module  504  may obtain load information  520  from receiving the downlink quality or the one or more historical downlink quality values of the target node  102 ,  106  from one or more devices. In another aspect, reception module  504  may obtain load information  520  by obtaining an uplink received signal strength indicator (RSSI) at the target node  102 ,  106 . In another aspect, reception module  504  may obtain load information  520  by receiving the load information  520  in a system information block from the target node  102 ,  106 . In another aspect, reception module  504  may obtain load information  520  by receiving the load information  520  in part by detecting a number of reselections or handovers performed to or from the target node  102 ,  106 . In still another aspect, reception module  504  may obtain information  520  include a location with respect to the target node  102 ,  106 . In such an aspect, the location information  520  may include a pathloss with respect to the target node  102 ,  106 . Thereafter, reception module  504  may provide the load information  520  to throughput comparison module  506  for processing. 
     Throughput comparison module  506  may receive an expected throughput value  522  from target node throughput estimation module  508 , compare it to a threshold, and generate a comparison value  524 . In such an aspect, the expected throughput value  522  may be estimated based in part on the load information  520 . In an aspect, serving node throughput module  514  may computer the throughput at a serving femto node  502  based on parameters specific to the serving femto node or parameters specific to the device. In such an aspect, the threshold used for comparison by target node throughput estimation module  508  may be based on the throughput  528  at the serving femto node  502 . Target node throughput estimation module  508  may provide the comparison value  524  to handover determination module  510  to determine whether to handover a device to the target node based in part on the comparison value  524 . In an aspect, handover determination module  510  may perform the determination through determining whether to modify one or more communication parameters  526  at a serving femto node  502  to cause handover of the device. In an aspect, transmission module  512  may be used to commute the modified communication parameters  526 . 
     The apparatus may include additional modules that perform each of the steps of the algorithm in the aforementioned flow chart of  FIG. 4 . As such, each block in the aforementioned flow chart of  FIG. 4  may be performed by a module and the apparatus may include one or more of those modules. The modules may be one or more hardware components specifically configured to carry out the stated processes/algorithm, implemented by a processor configured to perform the stated processes/algorithm, stored within a computer-readable medium for implementation by a processor, or some combination thereof 
       FIG. 6  is a diagram  600  illustrating an example of a hardware implementation for an apparatus  502 ′ employing a processing system  614 . The processing system  614  may be implemented with a bus architecture, represented generally by the bus  624 . The bus  624  may include any number of interconnecting buses and bridges depending on the specific application of the processing system  614  and the overall design constraints. The bus  624  links together various circuits including one or more processors and/or hardware modules, represented by the processor  604 , the modules  504 ,  506 ,  508 ,  510 ,  512 ,  514 , and the computer-readable medium  606 . The bus  624  may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further. 
     The processing system  614  may be coupled to a transceiver  610 . The transceiver  610  is coupled to one or more antennas  620 . The transceiver  610  provides a means for communicating with various other apparatus over a transmission medium. The processing system  614  includes a processor  604  coupled to a computer-readable medium  606 . The processor  604  is responsible for general processing, including the execution of software stored on the computer-readable medium  606 . The software, when executed by the processor  604 , causes the processing system  614  to perform the various functions described supra for any particular apparatus. The computer-readable medium  606  may also be used for storing data that is manipulated by the processor  604  when executing software. The processing system further includes at least one of the modules  504 ,  506 ,  508 ,  510 ,  512 , and  514 . The modules may be software modules running in the processor  604 , resident/stored in the computer-readable medium  606 , one or more hardware modules coupled to the processor  604 , or some combination thereof. The processing system  614  may be a component of the eNB  310  and may include the memory  332  and/or at least one of the TX data processor  314 , the RX data processor  342 , and the controller/processor  320 . 
     In one configuration, the apparatus  502 / 502 ′ for wireless communication includes means for obtaining load information regarding a target node, means for comparing an expected throughput at the target node, estimated based in part on the load information, to a threshold, and means for determining whether to handover a device to the target node based in part on the comparing. In an aspect, the apparatus  502 / 502 ′ means for obtaining receives a downlink quality at the target node and determines the load information based in part on the downlink quality. In another aspect, the apparatus  502 / 502 ′ means for obtaining compares the downlink quality to one or more historical downlink quality values at the target node to determine the load information. In another aspect, the apparatus  502 / 502 ′ means for obtaining obtains an uplink RSSI at the target node and determines the load information based on the uplink RSSI. In another aspect, the apparatus  502 / 502 ′ means for obtaining receives the load information in a system information block from the target node. In another aspect, the apparatus  502 / 502 ′ means for obtaining determines the load information based in part on detecting a number of reselections or handovers performed to or from the target node. 
     The aforementioned means may be one or more of the aforementioned modules of the apparatus  502  and/or the processing system  614  of the apparatus  502 ′ configured to perform the functions recited by the aforementioned means. As described supra, the processing system  614  may include the TX data Processor  314 , the RX data Processor  342 , and the controller/processor  330 . As such, in one configuration, the aforementioned means may be the TX data Processor  314 , the RX data Processor  342 , and the controller/processor  330  configured to perform the functions recited by the aforementioned means. 
     Referring now to  FIG. 7 , a wireless communication system  700  is illustrated in accordance with various embodiments presented herein. System  700  comprises a base station  702  that can include multiple antenna groups. For example, one antenna group can include antennas  704  and  706 , another group can comprise antennas  708  and  710 , and an additional group can include antennas  712  and  714 . Two antennas are illustrated for each antenna group; however, more or fewer antennas can be utilized for each group. Base station  702  can additionally include a transmitter chain and a receiver chain, each of which can in turn comprise a plurality of components associated with signal transmission and reception (e.g., processors, modulators, multiplexers, demodulators, demultiplexers, antennas, etc.), as is appreciated. 
     Base station  702  can communicate with one or more mobile devices such as mobile device  716  and mobile device  722 ; however, it is to be appreciated that base station  702  can communicate with substantially any number of mobile devices similar to mobile devices  716  and  722 . Mobile devices  716  and  722  can be, for example, cellular phones, smart phones, laptops, handheld communication devices, handheld computing devices, satellite radios, global positioning systems, PDAs, and/or any other suitable device for communicating over wireless communication system  700 . As depicted, mobile device  716  is in communication with antennas  712  and  714 , where antennas  712  and  714  transmit information to mobile device  716  over a forward link  718  and receive information from mobile device  716  over a reverse link  720 . Moreover, mobile device  722  is in communication with antennas  704  and  706 , where antennas  704  and  706  transmit information to mobile device  722  over a forward link  724  and receive information from mobile device  722  over a reverse link  726 . In a frequency division duplex (FDD) system, forward link  718  can utilize a different frequency band than that used by reverse link  720 , and forward link  724  can employ a different frequency band than that employed by reverse link  726 , for example. Further, in a time division duplex (TDD) system, forward link  718  and reverse link  720  can utilize a common frequency band and forward link  724  and reverse link  726  can utilize a common frequency band. 
     Each group of antennas and/or the area in which they are designated to communicate can be referred to as a sector of base station  702 . For example, antenna groups can be designed to communicate to mobile devices in a sector of the areas covered by base station  702 . In communication over forward links  718  and  724 , the transmitting antennas of base station  702  can utilize beamforming to improve signal-to-noise ratio of forward links  718  and  724  for mobile devices  716  and  722 . Also, while base station  702  utilizes beamforming to transmit to mobile devices  716  and  722  scattered randomly through an associated coverage, mobile devices in neighboring cells can be subject to less interference as compared to a base station transmitting through a single antenna to all its mobile devices. Moreover, mobile devices  716  and  722  can communicate directly with one another using a peer-to-peer or ad hoc technology as depicted. According to an example, system  700  can be a multiple-input multiple-output (MIMO) communication system. 
       FIG. 8  illustrates a wireless communication system  800 , configured to support a number of users, in which the teachings herein may be implemented. The system  800  provides communication for multiple cells  802 , such as, for example, macro cells  802 A- 802 G, with each cell being serviced by a corresponding access node  804  (e.g., access nodes  804 A -  804 G). As shown in  FIG. 8 , access terminals  806  (e.g., access terminals  806 A -  806 L) can be dispersed at various locations throughout the system over time. Each access terminal  806  can communicate with one or more access nodes  804  on a forward link (FL) and/or a reverse link (RL) at a given moment, depending upon whether the access terminal  806  is active and whether it is in soft handoff, for example. The wireless communication system  800  can provide service over a large geographic region. 
       FIG. 9  illustrates an example communication system  900  where one or more femto nodes are deployed within a network environment. Specifically, the system  900  includes multiple femto nodes  910 A and  910 B (e.g., femtocell nodes or H(e)NB) installed in a relatively small scale network environment (e.g., in one or more user residences  930 ). Each femto node  910  can be coupled to a wide area network  940  (e.g., the Internet) and a mobile operator core network  950  via a digital subscriber line (DSL) router, a cable modem, a wireless link, or other connectivity means (not shown). As will be discussed below, each femto node  910  can be configured to serve associated access terminals  920  (e.g., access terminal  920 A) and, optionally, alien access terminals  920  (e.g., access terminal  920 B). In other words, access to femto nodes  910  can be restricted such that a given access terminal  920  can be served by a set of designated (e.g., home) femto node(s)  910  but may not be served by any non-designated femto nodes  910  (e.g., a neighbor&#39;s femto node). 
       FIG. 10  illustrates an example of a coverage map  1000  where several tracking areas  1002  (or routing areas or location areas) are defined, each of which includes several macro coverage areas  1004 . Here, areas of coverage associated with tracking areas  1002 A,  1002 B, and  1002 C are delineated by the wide lines and the macro coverage areas  1004  are represented by the hexagons. The tracking areas  1002  also include femto coverage areas  1006 . In this example, each of the femto coverage areas  1006  (e.g., femto coverage area  1006 C) is depicted within a macro coverage area  1004  (e.g., macro coverage area  1004 B). It should be appreciated, however, that a femto coverage area  1006  may not lie entirely within a macro coverage area  1004 . In practice, a large number of femto coverage areas  1006  can be defined with a given tracking area  1002  or macro coverage area  1004 . Also, one or more pico coverage areas (not shown) can be defined within a given tracking area  1002  or macro coverage area  1004 . 
     Referring again to  FIG. 9 , the owner of a femto node  910  can subscribe to mobile service, such as, for example, 3G mobile service, offered through the mobile operator core network  950 . In another example, the femto node  910  can be operated by the mobile operator core network  950  to expand coverage of the wireless network. In addition, an access terminal  920  can be capable of operating both in macro environments and in smaller scale (e.g., residential) network environments. Thus, for example, depending on the current location of the access terminal  920 , the access terminal  920  can be served by a macro cell access node  960  or by any one of a set of femto nodes  910  (e.g., the femto nodes  910 A and  910 B that reside within a corresponding user residence  930 ). For example, when a subscriber is outside his home, he is served by a standard macro cell access node (e.g., node  960 ) and when the subscriber is at home, he is served by a femto node (e.g., node  910 A). Here, it should be appreciated that a femto node  910  can be backward compatible with existing access terminals  920 . 
     A femto node  910  can be deployed on a single frequency or, in the alternative, on multiple frequencies. Depending on the particular configuration, the single frequency or one or more of the multiple frequencies can overlap with one or more frequencies used by a macro cell access node (e.g., node  960 ). In some aspects, an access terminal  920  can be configured to connect to a preferred femto node (e.g., the home femto node of the access terminal  920 ) whenever such connectivity is possible. For example, whenever the access terminal  920  is within the user&#39;s residence  930 , it can communicate with the home femto node  910 . 
     In some aspects, if the access terminal  920  operates within the mobile operator core network  950  but is not residing on its most preferred network (e.g., as defined in a preferred roaming list), the access terminal  920  can continue to search for the most preferred network (e.g., femto node  910 ) using a Better System Reselection (BSR), which can involve a periodic scanning of available systems to determine whether better systems are currently available, and subsequent efforts to associate with such preferred systems. Using an acquisition table entry (e.g., in a preferred roaming list), in one example, the access terminal  920  can limit the search for specific band and channel. For example, the search for the most preferred system can be repeated periodically. Upon discovery of a preferred femto node, such as femto node  910 , the access terminal  920  selects the femto node  910  for camping within its coverage area. 
     A femto node can be restricted in some aspects. For example, a given femto node can only provide certain services to certain access terminals. In deployments with so-called restricted (or closed) association, a given access terminal can only be served by the macro cell mobile network and a defined set of femto nodes (e.g., the femto nodes  910  that reside within the corresponding user residence  930 ). In some implementations, a femto node can be restricted to not provide, for at least one access terminal, at least one of: signaling, data access, registration, paging, or service. 
     In some aspects, a restricted femto node (which can also be referred to as a Closed Subscriber Group H(e)NB) is one that provides service to a restricted provisioned set of access terminals. This set can be temporarily or permanently extended as necessary. In some aspects, a Closed Subscriber Group (CSG) can be defined as the set of access nodes (e.g., femto nodes) that share a common access control list of access terminals. A channel on which all femto nodes (or all restricted femto nodes) in a region operate can be referred to as a femto channel. 
     Various relationships can thus exist between a given femto node and a given access terminal For example, from the perspective of an access terminal, an open femto node can refer to a femto node with no restricted association. A restricted femto node can refer to a femto node that is restricted in some manner (e.g., restricted for association and/or registration). A home femto node can refer to a femto node on which the access terminal is authorized to access and operate on. A guest femto node can refer to a femto node on which an access terminal is temporarily authorized to access or operate on. An alien femto node can refer to a femto node on which the access terminal is not authorized to access or operate on, except for perhaps emergency situations (e.g.,  911  calls). 
     From a restricted femto node perspective, a home access terminal can refer to an access terminal that authorized to access the restricted femto node. A guest access terminal can refer to an access terminal with temporary access to the restricted femto node. An alien access terminal can refer to an access terminal that does not have permission to access the restricted femto node, except for perhaps emergency situations, for example,  911  calls (e.g., an access terminal that does not have the credentials or permission to register with the restricted femto node). 
     For convenience, the disclosure herein describes various functionality in the context of a femto node. It should be appreciated, however, that a pico node can provide the same or similar functionality as a femto node, but for a larger coverage area. For example, a pico node can be restricted, a home pico node can be defined for a given access terminal, and so on. 
     A wireless multiple-access communication system can simultaneously support communication for multiple wireless access terminals. As mentioned above, each terminal can communicate with one or more base stations via transmissions on the forward and reverse links. The forward link (or downlink) refers to the communication link from the base stations to the terminals, and the reverse link (or uplink) refers to the communication link from the terminals to the base stations. This communication link can be established via a single-in-single-out system, a MIMO system, or some other type of system. 
     The various illustrative logics, logical blocks, modules, components, and circuits described in connection with the embodiments disclosed herein may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but, in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. Additionally, at least one processor may comprise one or more modules operable to perform one or more of the steps and/or actions described above. An exemplary storage medium may be coupled to the processor, such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. Further, in some aspects, the processor and the storage medium may reside in an ASIC. Additionally, the ASIC may reside in a user terminal In the alternative, the processor and the storage medium may reside as discrete components in a user terminal 
     In one or more aspects, the functions, methods, or algorithms described may be implemented in hardware, software, firmware, or any combination thereof If implemented in software, the functions may be stored or transmitted as one or more instructions or code on a computer-readable medium, which may be incorporated into a computer program product. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage medium may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, substantially any connection may be termed a computer-readable medium. For example, if software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and blu-ray disc where disks usually reproduce data magnetically, while discs usually reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media. 
     While the foregoing disclosure discusses illustrative aspects and/or embodiments, it should be noted that various changes and modifications could be made herein without departing from the scope of the described aspects and/or embodiments as defined by the appended claims. Furthermore, although elements of the described aspects and/or embodiments may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated. Additionally, all or a portion of any aspect and/or embodiment may be utilized with all or a portion of any other aspect and/or embodiment, unless stated otherwise.