WIRELESS NETWORK

TECHNICAL FIELD

[0001] The present disclosure relates generally to wireless networks, and specifically to systems and methods for optimized access messaging in a wireless network.

J O fi U D

[0002] Various wireless technologies (e.g., 3G, 4G. 3GPP Long Term Evolution (LTE), LTE-Advanced (LTE-A), Worldwide Interoperability for Microwave Access (WiMAX), etc) allow for the use of small base stations, generally referred to herein as small ceils (e.g., femto base stations or pico base stations in WiMAX or Home Node B (HeNB), pico base stations or generic-ally designated as small cell base stations in 3 GPP LTE specifications). The user or a wireless service provider's technician installs the small cell in the user's home or office to improve the user experience. The small cell's backhaul connection to the wireless service provider's network is provided via the user's network access (e.g., digital subscriber line (DSL) or provided by the wireless carrier). The small ceil exhibits a similar wireless behavior (e.g., uses the same air interface protocol) as the wireless service provider's other base stations (e.g., macro base stations (mBSs) and/or relay stations). The small cell may allow for the handover from the niBS to the small cell to be accomplished without the user noticing (e.g., similar to the handover from one niBS to another). Small cells may be useful in machine to machine (M2M) communications that are engineered to communicate with little or no human support, M2M communications in large industrial or machine residential networks may require the connection of over 30,000 machine User Equipment (UE) devices per mBS. Small cells may be able to assist in offloading a main cell's excess data traffic, including M2M traffic, thus increasing the overall cell throughput and improving the user experience. Small cells are expected to enable significant increases in the overall throughput of a macro cell and thus increasing die overall spectrum efficiency of the respective macro cell NUMMARY

[0003] in accordance with one or more embodiments of the present disclosure, a method is provided for managing wireless network traffic that includes designating a first resource block of a macro base station and a second resource block of a small cell base station for access by a physical random access channel (PRACH). The method further includes designating a first random access subframe associated with the first resource block for access by a random access channel message. The first random access subframe has a first allocation of random access signatures that are configured to receive a plurality of random access requests. The method additionally includes designating a second random access subframe associated with the second resource block for access by a random access channel message, The second random access subframe is time-aligned with the first random access subframe and has a second allocation of random access signatures that are configured to receive a plurality of random access requests.

[0004] In accordance with another embodiment of the present disclosure, one or more non-transitory computer-readable media is provided embodying logic that, when executed by a processor, is configured to perform operations that include designating a first resource block of a macro base station and a second resource block of a small cell base station for access by a PRACH. The operations further include designating a first random access subframe associated with the first resource block for access by a random access channel message. The first random access subframe has a first allocation of random access signatures that are configured to receive a plurality of random access requests. The operations additional ly include designating a second random access subframe associated with the second resource block for access by a random access channel message. The second random access subframe is time-aligned with the first random access subframe and has a second allocation of random access signatures that are configured to receive a plurality of random access requests.

[0§0S] The object and advantages of the invention will be realized and attained at least by the features, elements, and combinations particularly pointed out in the claims. It Is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed.

[0006] For a more complete understanding of the present disclosure and its features and advantages, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which:

[0007] FIGURE 1 illustrates an example wireless network using overlaid small cell (OSC) topology, in accordance with one embodiment of the present disclosure;

[0008] FIGURE 2 illustrates example apparatuses that may facilitate the various components of FIGURE 1 , in accordance with one embodiment of the present disclosure;

[0009] FIGURE 3 illustrates an example allocation in a plurality of non-time- aligned random access subframes as part of time-aligned resource blocks utilized by base stations located in the same vicinity, in accordance with one embodiment of the present disclosure;

[0010] FIGURE 4 illustrates an example allocation in a plurality of time-aligned random access subframes and resource blocks utilized by base staiions located in the same vicinity, in accordance with one embodiment of the present disclosure;

[0011] FIGURE 5 illustrates an example configuration of multiple macro base stations (mBSs) and a physical random access channel (PRACH) immunity radius in the case where multiple mBSs re-use the same PRACH random access signature set, in accordance with one embodiment of the present disclosure;

[0012] FIGUR E 6 illustrates an example of a cluster of cells with multiple immunity radii, in accordance with one embodiment of the present disclosure;

[00I3J FIGURE 7 A illustrates an example cell cluster with an OSC topology configured to optimize the PRACH random access signature set allocation, in accordance with one embodiment of ihe present disclosure;

[0014] FIGURE 7B illustrates an example network having a semi-static PRACH random access signature set scheduling configuration, in accordance with one embodiment of the present disclosure; and

[0015] FIGURE 8 illustrates a flow chart of an example method for random access signature set optimization in a wireless network, in accordance with one embodiment of the present disclosure. [0016] FIGURE 1 illustrates an example wireless network 100 using overlaid small cell (OSCs) topology, in accordance with one embodiment of the present disclosure. Network 100 may include one or more co-located macro base stations (rnBS) 102, one or more endpoints 104a-e (collectively referred to as endpoints 104), Network 100 may provide wireless coverage for any suitable number of endpoints 104 over a geographic area such as cell 1 10. For example, rnBS 102 may be used to provide wireless coverage for an entire building, a city block, a campus, or any contiguous other area. Cell 1 10 may have any suitable coverage shape, such as a circular shape depicted in FIGURE 1 . Cell 1 10 may also have any suitable size. For example, cell 1 10 may have radius 122 of approximately three kilometers.

[0017] rnBS 102 may be configured to communicate with one or more endpoints 104 using wireless communication via one or more ports (not expressly shown). As used herein, rnBS 102 may refer to a iransmission site, a remote transmission site, a Radio Element Control, an Evolved Node B (e B), a Baseband Unit, a Radio Element, and/or a Remote Radio Head (RRH). rnBS 102 may include any combination of hardware, software embedded in a. computer readable medium, and/or encoded logic incorporated in hardware or otherwise stored (e.g., firmware) to implement any number of communication protocols that allow for wired or wireless exchange of information in network 100. rnBS 102 may be operable to send control messages and data traffic to endpoints 104. niBS 102 may use any suitable technologies or protocols, e.g., Common Public Radio interface (CPRI), to communicate with other mBS 102. in some embodiments, rnBS 102 may coordinate with other mBS 102 to communicate jointly with endpoint 104.

[0018] in some embodiments of the present disclosure, mBS 102 may be installed on a mobile wireless transmission tower such as those operated by mobile wireless service providers. For example, mBS 102 may be configured to transmit mobile wireless data that complies with the 3rd Generation Partnership Project (3GPP) protocols, in the example illustrated in FIGURE 1 , mBS 102 may be configured to transmit and/or receive wireless data that complies with the Long Term Evolution (Ϊ..ΤΈ) standard. In the same or alternative embodiments, mBS 102 may be configured to transmit and/or receive wirelessly data that complies with other protocols, including later releases of 3GPP or other fourth- (or later) generation protocols such as LTE-Advanced (LTE-A),

[0019] mBS 102 may also be coupled to any network or combination of networks capable of transmitting, receiving, and processing signals, data, and/or messages supporting web pages, e-mail, text, chat, voice over IP (VoIP), instant messaging, and/or any other suitable application in order to provide services and support data transmissions to endpoints 104. For example, mBS 102 may be coupled to one or more local area networks (LANs), wide area networks (WANs), metropolitan area networks (MANs), enabling the connection to global distributed networks such as the internet, or any other form of wireless or wired networking. As an example, mBS 102 may be coupled to a core infrastructure network 1 12, which may include server 108, via a LAN 1 14,

[0020] Network 100 may also include one or more and one or more small cell base stations (scBS) 1 18a-d (collectively referred to as scBS 1 18). scBSs 1 18 may be small cell evolved Node Bs (seNBs), Ffome evolved Node-B (HeNB), and/or any other suitable devices, in some embodiments of the present disclosure, scBS 1 18 may be any electronic device configured to switch and/or aggregate mobile wireless data for communication among other devices. In some embodiments of the present disclosure, scBS 1 18 may include memory and one or more processors configured to execute instructions stored on that memory.

|ΌΘ21] scBS 1 18 may provide wireless coverage and services for any suitable number of endpoints 104 over a geographic, area such as overlaid small cell (OSC) 116a-d (collectively referred to as OSCs 1 16), OSC 1 16 may be a small cell associated with scBS 1 18 that may be located wholly or partially within the coverage area of mBS 102, e.g., cell 1 10. In some embodiments of the present disclosure, OSC 1 16 may also overlap with multiple neighboring cells 1 10. OSC 1 16 may have any suitable coverage shape, such as a circular shape as depicted in FIGURE 1 . OSC S 16 may have any suitable size. For example, OSC 1 16 may have coverage radius 124 of approximately half of a kilometer. Although OSCs 1 16a-d may be shown in FIGURE 1 as having approximately the same size, each OSC 1 16 may be of any suitable size. In some embodiments of the present disclosure, it may be necessary or desirable for a home or business to have one or more OSC 1 16 deployed throughout the home or business. In such a manner, a mobile wireless provider may optimize the coverage of the mobile wireless network indoors or to poor coverage areas, which might be more difficult and/or expensive to reach via conventional mobile wireless coverage techniques.

[0022] in some embodiments of the present disclosure, scBS 1 18 may communicate with the mobile wireless provider's core network and/or mBS 102 over a link 132 that may be a wireline link such as digital subscriber line (DSL), optica! liber, or other appropriate wireline link, or an appropriate wireless link. In some embodiments of the present disclosure, this may be beneficial to both the user and the wireless service provider, in some embodiments of the present disclosure, OSC 1 16 may be a co-channel OSC that operates within mBS 102 broadband spectrum by- reusing the same frequency as mBS 102,

[0023] Although reference is made above and below with reference to FIGURES 2-8 to LTE as the mobile wireless technology, other technologies, standards, and/or protocols may be implemented without departing from the scope of the present disclosure. For example, the systems and methods described herein may also be applied to worldwide interoperability for microwave access (WiMAX) as another orthogonal frequency-division multiplexing (OFDM) mobile wireless technology communication or other suitable wireless technology.

[0024] When OSC 1 16 is active, the user, the user equipment, the radio access network, or some combination thereof may be able to offload some portion of the mobile wireless data traffic onto the local area network for communication back to the core network. This may have the benefit of lowering the traffic level on mBS 102 as well as improving performance for the user. In some configurations of scBS 1 18, this "data offload" process may be performed by a number of different approaches.

0Θ25] Endpoints 104 may be any electronic device configured to receive and/or transmit wireless data, messages, and/or signals to and from other endpoints 104, mBS 102, and/or scBS 1 18. For example, endpoint 104 may be a mobile wireless telephone, tablet computer, laptop computer, desktop computer, PDA, mobile wireless modem, VoIP phone, wireless measurement device, wireless sensor, wireless sensor embedded in a machine, and/or other device configured to communicate with mBS 102 and/or scBS 1 18. Endpoints 104 may provide data or network services to a human and/or machine user through any suitable combination of hardware, software embedded in a computer readable medium, real-time processing system, and/or encoded logic incorporated in hardware or otherwise stored (e.g., firmware), Endpoints 104 may also include unattended or automated systems, gateways, other intennediate components or other devices that may send or receive data, messages, and/or signals. Various types of information may be sent to or from endpoints 104. As an example, endpoint 104 may send identification data and status data to mBS 102 and/or scBS 1 18.

[0026] In some embodiments, machine to machine (M2M) communications, also known as Machine Type Communications (MTC), may utilize endpoints 104 in the form of machine user equipment (M-UE). M2M networks may have traffic patterns significantly different from human mobile traffic. For example, sensor networks in industrial applications, smart grid/meters in residential utility applications, and/or smart home networks may include large numbers of machine UEs. As another example, in some large industrial applications, network 100 may be required to accommodate large numbers of machine UEs, e.g., up to more than approximately 30,000 devices per cell 1 10. Network 100 may include only machine UEs in the case of a M2M network, or network 100 may be a mix of human mobile devices, such as mobile wireless handsets, and machine U Es in a human/machine network, . Further, machine UEs may exhibit infrequent and/or bursty communication and traffic patterns,

[0027J As described in more detail below with reference to FIGURES 2-8, mBS 102 and/or scBS 1 18 may be configured to execute instructions performing the optimization routines discussed below, in other configurations, responsibilities for various portions may be distributed among the components of network 100.

[0028] in some embodiments of the present disclosure, a concentrator 130 may be utilized that may be in communication with mBS 102, server 108, scBS 1 18, and/or an other suitable equipment. Concentrator 130 may include a processor system, memory, ports, and/or any other suitable components. Concentrator 130 may be configured to gather messages from all endpoints 104 within cell 1 10 or OSC 116. Concentrator 130 may be configured to address the messages received from endpoints 104, e.g., add headers, to forward the messages onto mBS 102, server 108, scBS 1 18, and/or any other suitable destination. Further, concentrator 130 may be embedded in or co-located with mBS 102. [0029] Although FIGURE 1 illustrates example network 100 as having one mBS 102, multiple endpoints 104, and four scBSs 1 18, it should he understood that these examples are provided to aid in understanding and any number of any given devices and/or sub-systems may be present in a given configuration without departing from the scope of the present disclosure, it should also be understood that the number of any given component may change over time. For example, the number and identity of endpoints 104 present within range of a given scBS 1 18 may change over time as users move in and out of scBS 1 18 coverage,

[0030] Further, although FIGU RE 1 illustrates only one topology of the system comprising mBS 102, endpoints 104, and scBSs 1 18, a number of such iterations may be present within network 100 without departing from the scope of the present disclosure. For example, there may be a plurality of OSCs 1 16 present within range of a given cell 1 10. in other embodiments, network 100 may not include mBS 102, Further, mBS 102 and scBS 1 18 may be configured to communicate with neighboring rnBS 102 and scBS 1 18.

[0031] FIGURE 2 illustrates example apparatuses that may facilitate th operations of various components of FIGURE 1 , in accordance with one embodiment of the present disclosure. FIGURE 2 includes an example communications system 200 with two example endpoints 104 and example mBS 102. Although i llustrated utilizing mBS 102, alternatively system 200 may include scBS 1 18 having the same illustrated components as mBS 102, Communications system 200 may correspond to at least a portion of network 100 of FIGURE 1 , Endpoints 104 and mBS 102 may each include one or more portions of one or more computer systems,

|0I)32] System 200 may allow for multiple-input/ ^' rnuliiple output (MIMO) transmission where multiple antennas are used for transmitting and receiving wireless messages and/or signals. Additionally, system 200 may be configured to perform Coordinated Multi-point Processing (CoMP) to coordinate and combine the transmission of messages and/or signals used in MIMO transmission. The CoMP processing may perform DL CoMP transmission in which multiple mBS 102 jointly communicate with endpoints 104 and/or multiple endpoints 104 communicate with mBS 102.

[0033] Endpoints 104 may communicate with mBS 102 using wireless communication via air interface using one or more antenna ports 216. For example, endpoint 104a may communicate with mBS 102 via air interface using antenna ports 216a and 216b. Endpoint 104b may communicate with mBS 102 via air interface vising antenna ports 216e and 216d. Endpoints 104 may communicate with mBS 102 using any of a variety of different wireless technologies, including, but not limited to, 1..ΪΚ. and LTE-A protocol as defined in the 3 GPP Release 1 1 or beyond. In some embodiments of the present disclosure, endpoints 104 may coordinate with one more other endpoints 104 to communicate jointly with mBS 102, in such embodiments, endpoints 104 may coordinate with each other to communicate with mBS 102 using a MIMO transmission/reception scheme where multiple transmitting antenna ports 216 may equip different endpoints 104, while one or more transmitting/receiving antenna ports 218 are located at the mBS 102, For example, endpoints 104 may communicate with mBS 102 using a DL and UL CoMP schemes backed by MIMO transmission/reception as defined in 3GPP standards. During such a MIMO transmission, endpoint 104 may wirelessly communicate using multiple layered data streams to mBS 102 via one or more wireless connections between antenna ports 216 and one or more antenna port 218 of mBS 102,

[0034 j The components of endpoints 104 and mBS 102 may comprise any suitable physical form, configuration, number, type and/or layout, As an example, and not by way of limitation, endpoint 104 and/or mBS 102 may comprise an embedded realtime processing system, computer system, a system-on-chip (SOC), a single-board computer system (SBC) (for example, a eomputer-on~moduie (COM ) or system-ort- modu!e (SOM)), a desktop computer system, a laptop or notebook computer system, an interactive kiosk, a mainframe, a mesh of computer systems, a mobile telephone, a personal digital assistant (PDA), a server, or a combination of two or more of these. Where appropriate, endpoint 104 and/or mBS 102 ma include one or more computer systems or be embedded in a multiple processor system; be unitary or distributed; span multiple locations; span multiple machines; or reside in a cloud, which may include one or more cloud components in one or more networks.

[0035] In the depicted embodiment, endpoints 104a and 104b and mBS 102 each include their own respective processor system 21 3 , 221 , and 231 ; memory system 213, 223, and 233; storage 215, 225, and 235; interface 217, 227, and 237; and bus 212, 222, and 232. Although a particular wireless communications system is depicted having a particular number of particular components in a particular arrangement, this disclosure contemplates any suitable wireless communications system 200 having any suitable number of any suitable components in any suitable arrangement. For simplicity, similar components of endpoints 104a, 104b and mBS 102 will be discussed together, However, it is not necessary for these devices to have the same components, or the same type of components, or be configured in the same manner, For example, processor system 21 1 may be implemented as an application specific integrated circuit (ASK ) or System-on-Chip (SoC),

[0036] Processor systems 21 1 , 221 and 231 may include one or more microprocessors, controllers, or any other suitable computing device, resource, or combination of hardware, software and/or encoded logic based on a real time operating system (RTOS) operable to provide, either alone or in conjunction with other components (e.g., memory systems 213, 223, and 233, respectively), wireless networking functionality. Such functionality may include supporting various wireless features discussed herein. For example, processor system 231 may be configured to analyze and/or process data, messages, and/or signals communicated between mBS 102 and endpoints 104 via channels 224. Further, processor systems 21 1 and 221 of endpoints 104a and 104b may be configured to analyze messages, signals, and/or data communicated from mBS 102 via channels 224.

[0037] ^" In some embodiments, processor systems 23 1 , 221 , and 231 may include hardware for executing instructions, such as those making up a computer program and/or real time instructions supported by a RTOS, As an example, and not by way of limitation, to execute instructions, processor systems 21 1 , 221 , and 231 may retrieve (or fetch) instructions from an internal register, an internal cache, memory systems 213, 223, or 233, respectively, or storage 215, 225 or 235, respectively; decode and execute them; and then write one or more results to an internal register, an internal cache, memory systems 233, 223, or 233, respectively, or storage 215, 225, or 235. respectively.

[0038] In some embodiments, processor systems 23 1 , 221 , and 231 may include one or more internal caches for data, instructions, or addresses, This disclosure contemplates processor systems 21 1 , 221 , and 231 including any suitable number of any suitable internal caches, where appropriate. As an example, and not by way of limitation, processor systems 21 1 , 221 , and 231 may include one or more instruction caches, one or more data caches, and one or more translation lookaside buffers (TLBs) and/or multiple layered buffers, Instructions in the instruction caches may be copies of instructions in memory systems 213, 223, or 233, respectively, or storage 215. 225, or 235, respectively, and the instruction caches may speed up retrieval of those instructions by processor systems 21 1 , 221, or 231, respectively. Data in the data caches may be copies of data in memory systems 213, 223, or 233, respectively, or storage 215, 225, or 235, respectively, for instructions executing at processor systems 21 1 , 221 , or 231, respectively, to operate on; the results of previous instructions executed at processor systems 21 3 , 221 , or 231 for access by subsequent instructions executing at processor systems 21 1 , 221, or 231. or for writing to memory systems 213, 223, or 233, respectively, or storage 21 5, 225, or 235, respectively; or other suitable data. The data caches may speed up read or write operations by processor systems 21 1 , 221 , or 231 , The multiple layered buffers may speed up virtual-address translations for processor systems 21 1 , 221 , or 231 , In some embodiments, processor systems 21 1 , 221 , and 231 may include one or more internal registers for data, instructions, or addresses. Depending on the embodiment, processor systems 21 1, 221 , and 231 may include any suitable number of any suitable internal registers, where appropriate. Where appropriate, processor systems 21 1 , 22 L and 231 may include one or more arithmetic logic units (ALUs); be a multi-core processor: include one or more processor systems 21 1 ; or any other suitable processor.

[0039] Memory systems 213, 223, or 233 may be any form of volatile or nonvolatile memory including, without limitation, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), flash memory, removable media, or any other suitable local or remote nieinory component or components. In some embodiments, memory systems 213, 223, or 233 may include random access memory (RAM). This RAM may be volatile memory, where appropriate. Where appropriate, this RAM may be dynamic RAM (DRAM) or static RAM (SRAM). Moreover, where appropriate, this RAM may be single-ported or multi-ported RAM, or any other suitable type of RAM or memory. Memory systems 213, 223, or 233 may include one or more memories 213, 223, or 233, respectively, where appropriate. Memory systems 213, 223, or 233 may store any suitable data or information utilized by endpoints 104a, 104b, or mBS 102, respectively, including software embedded in a computer readable medium, and/or encoded logic incorporated in hardware or otherwise stored (e.g., firmware). In some embodiments, memory systems 213, 223, or 233 may include main memory for storing instructions for processor systems 21 1 , 221 , or 231, respectively, to execute or data for processor systems 21 1 , 221 , or 2 1 to operate on. In some embodiments, one or more memory management units (MMUs) may reside between processor systems 21 1, 22.1 , or 231 and memory systems 213, 223, or 233, respectively, and facilitate accesses to memory systems 21 , 223, or 233 requested by processor systems 21 1 , 221 , or 231, respectively.

[0040] As an example, and not by way of limitation, endpoints 104a, 104b, or mBS 102 may load instructions and/or addresses from storage 21 5, 225, or 235, respectively, or another source (such as, for example, another computer system, another base station, or a remote transmission site) to memory systems 213, 223, or 233, respectively. Processor systems 21 1, 221, or 231 may then load the instructions from memory systems 213, 223, or 233, respectively, to an internal register or internal cache. To execute the instructions, processor systems 21 1 , 221 , or 231 may retrieve the instructions from the internal register or internal cache and decode them. During or after execution of the instructions, processor systems 21 1 , 221 , or 231 may write one or more results (which may be intermediate or final results) to the internal register or internal cache. Processor systems 21 1 , 221 , or 231 may then write one or more of those results to memory systems 213, 223, or 233, respectively. In some embodiments, processor systems 21 1 , 221. or 231 may execute only instructions in one or more internal registers and/or internal caches or in memory systems 213, 223, or 233, respectively (as opposed to storage 215, 225, or 235, respectively, or elsewhere), and may operate only on data in one or more internal registers or internal caches or in memory systems 213, 223, or 233, respectively (as opposed to storage 215, 225, or 235, respectively, or elsewhere),

[0041 ] in some embodiments, storage 215, 225, or 235 may include mass storage for data, instructions, and/or addresses. As an example, and not by way of limitation, storage 215, 225, or 235 may include a hard disk drive (HDD), a floppy disk drive, flash memory, an optical disc, a magneto-optical disc, magnetic tape, or a Universal Serial Bus (USB) drive or a combination of two or more of these. Storage 215, 225, or 235 may include removable or non-removable (or fixed) media, where appropriate. In some embodiments, storage 215, 225, or 235 may be non-volatile, solid-state memory. In some embodiments, storage 215, 225, or 235 may include read-only memory (ROM). Where appropriate, this ROM may be mask-programmed ROM, programmable ROM (PROM), erasable PROM (EPROM). electrically erasable PRO (EEPROM), electrically alterable ROM (EAROM), or flash memory or a combination of two or more of these. Storage 215, 225, or 235 may take any suitable physical form and may comprise any suitable number or type of storage. Storage 215, 225, or 235 may include one or more storage control units facilitating communication between, processor systems 21 1 , 221 , or 231, respectively, and storage 215, 225, or 235, respectively, where appropriate.

[0042] In some embodiments, interfaces 217, 227, or 237 may include hardware, encoded software, or both providing one or more interfaces for communication (such as, for example, packet-based communication) between endpoints 104, mBS 102, any networks, any network devices, and/or any other computer systems, As an example, and not by way of limitation, communication interface 217, 227, or 237 may include a network interface controller (NIC) or network adapter for communicating wiih an Ethernet or other wire-based network and/or a wireless NIC (WNIC) or wireless adapter for communicating with a wireless network.

[0043] in some embodiments, interfaces 217 or 227 comprise one or more radios (or radio transceivers) coupled to one or more antenna ports 216. in such an embodiment, interface 217 or 227 receives digital data that is to be sent out to wireless devices, such as mBS 102, via a wireless connection, The radio transceivers may convert the digital data into a radio signal having the appropriate center frequency, bandwidth, transmission power, and/or other suitable interface parameters. Similarly, the radio transceivers may convert radio signals received via one or more receiving antennas into digital data to be processed by, for example, processor systems 21 1 or 221, respectively. Interface 237 of rnBS 102 may be configured to perform similar operations via processor system 231 and antenna port 218.

[Θ044] Depending on the embodiment, interface 217, 227, or 237 may be any type of interface suitable for any type of network for which communications system 200 is used. As an example, and not by way of limitation, communications system 200 may be coupled to a supporting core network, an ad-hoc network, a personal area network (PAN), a local area network (LAN), a wide area network (WAN), a metropolitan area network (MAN), or one or more portions of the Internet or a combination of two or more of these. One or more portions of one or more of these networks may be wired or wireless. As an example, communications system 200 may communicate with a wireless PAN (WPA ) (such as, for example, a BLUETOOTH WPA.N), a WI-FI network, a WI-MAX network, an LTE network, an LTE-A network, a mobile wireless telephone and/or data network (for example, a Global System for Mobile Communications (GSM) network), or any other suitable wireless network or a combination of two or more of these. Endpoints 1 4a, 104b, and mBS 102 may include any suitable interface 217, 227, or 237, respectively, for any one or more of these networks, where appropriate.

[0045] in some embodiments, interface 217, 227, or 237 may include one or more interfaces for one or more I/O devices. One or more of these I/O devices may enable communication between a person and endpoints 104 and/or mBS 102. As an example, and not by way of limitation, an I/O device may include a keyboard, keypad, microphone, monitor, mouse, printer, scanner, speaker, still camera, stylus, tablet, touch screen, trackball, video camera, another suitable I/O device or a combination of two or more of these. An I/O device may include one or more sensors. Some embodiments may include any suitable type and/or number of I/O devices and any suitable type and/or number of interface 217, 227, or 237 for them. Where appropriate, interface 217, 227, or 237 may include one or more drivers enabling processor systems 211 , 221 , o 231 , respectively, to drive one or more of these I/O devices, interface 21 7, 227, or 237 may be coupled to radio transceivers where appropriate.

[0046J Bus 212, 222, or 232 may be single or multiple threaded and may include any suitable combination of hardware, software embedded in a computer readable medium, and/or encoded logic incorporated in hardware or otherwise stored (e.g., firmware) to couple components of endpoint 104 and mBS 102 to each other. As an example, and not by way of limitation, bus 212, 222, or 232 may include an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced industry Standard Architecture (EISA) bus, a front-side bus (FSB), a HYPER TRANSPORT (HT) interconnect, an Industry Standard Architecture (ISA) bus, an INFINIBAND interconnect, a low-pin-count (LPC) bus, a memory bus, a Micro Channel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCE Express (PCi-X) bus, a serial advanced technology attachment (SATA) bus, a Video Electronics Standards Association local (VLB) bus, or any other suitable bus or a combination of two or more of these, Bus 212, 222. or 232 may include any number, type, and/or configuration of bus 212, 222, or 232, where appropriate, In some embodiments, one or more buses 212, 222, or 232 (which may each include an address bus and a data bus) may couple processor systems 21 1, 221 , or 231 , respectively, to memory systems 213. 223, or 233. respectively. Bus 212, 222, or 232 may include one or more memory buses, and may be specialized and dedicated multithreaded busses.

[0047] Herein, reference to a computer-readable storage medium encompasses one or more tangible computer-readable storage media possessing structures. As an example, and not by way of limitation, a computer-readable storage medium may include a semiconductor-based or other integrated circuit (IC) (such, as for example, a field-programmable gate array (FPGA) or an application-specific IC (ASIC)), a hard disk, an HDD, a hybrid hard drive (HHD), an optical disc, an optical disc drive (ODD), a magneto-optical disc, a magneto-optical drive, a floppy disk, a floppy disk drive (FDD), magnetic tape, a holographic storage medium, a solid-state drive (SSD) a RAM-drive, a SECURE DIGITAL card, a SECURE DIGITAL drive, a flash memory card, a flash memory drive, or any other suitable tangible computer-readable storage medium or a combination of two or more of these, where appropriate.

|0048] Some embodiments may include one or more computer-readable storage media implementing any suitable storage. In some embodiments, a computer- readable storage medium implements one or more portions of processor systems 21 1 , 221, or 231 (such as, for example, one or more internal registers or caches), one or more portions of memory systems 213, 223, or 233, one or more portions of storage 215, 225, or 235. or a combination of these, where appropriate. In some embodiments, a computer-readable storage medium implements RAM or ROM. In some embodiments, a computer-readable storage medium implements volatile or persistent memory. In some embodiments, one or more computer-readable storage media embody encoded software.

[0049] Herein, reference to encoded software may encompass one or more applications, bytecode, one or more computer programs, one or more executables, one or more instructions, logic, machine code, one or more scripts, one or more RT03 routines, or source code, and vice versa, where appropriate, that have been stored or encoded in a computer-readable storage medium. In some embodiments, encoded software includes one or more applicaiion programming interfaces (APIs) stored or encoded in a computer-readable storage medium. Some embodiments may use any suitable encoded software written or otherwise expressed in any suitable programming language or combination of programming languages stored or encoded in any suitable type or number of computer-readable storage media. In some embodiments, encoded software may be expressed as source code or object code. In some embodiments, encoded software is expressed in a RTOS programming higher- level programming language, such as, for example, C, Perl, or a suitable extension thereof. In some embodiments, encoded software is expressed in a lower-level programming language, such as assembly language (or machine code), in some embodiments, encoded software is expressed in JAVA, in some embodiments, encoded software is expressed in Hyper Text Markup Language (HTML), Extensible Markup Language {XML), real time OS (RTOS), or other suitable markup language.

[005(1] Accordingly, the above-mentioned components of endpoints 104 and mBS 102 may enable endpoints 104 and mBS 102 to perform operations such as joint data link transmission according to the present disclosure. Modifications, additions, or omissions may be made to FIGURE 2 without departing from the scope of the present disclosure. For example, any of the options or features described herein may be utilized in combination with the illustrated embodiments of FIGURES 1 and 2 and/or any number of the other options or features also described herein as would be understood by one of ordinary skill in the art. As another example, mBS 102 may include one or more real time physical (PHY) layer processors, which may be further connected to one or more PHY/media access control (MAC) co-processors coupled to a fast access RAM and a permanent ROM memory, T he real time PHY processor may be configured to process a plurality of messages stored into one or more subframes received from one or more endpoints i 04.

[0051] A network access request, (e.g., message and/or user packet request) transmitted by endpoints 104 may be sent using a Random Access Channel (RACH) backed by a Physical Random Access Channel (PRACH). A PRACH may be a shared channel used for initial network access between endpoini 104 and mBS 102 and/or scBS 1 18. A PRACH may also be utilized for communication of unscheduled access related messages such as when endpoint 104 exits sleep mode, loses power, attempts to connect to the network, or executes a handover. Thus, for example, the PRACH may be used to transmit a last gasp message (LGM), mass scale event iriggered (MSET) device identification, and/or other message from endpoints 104 to mBS 102 and/or scBS 1 18 across and/or utilizing an LTE, LTE- A network, or other wireless network. During M2M mass event scenarios, (e.g., after a large scale power outage scenario) impacting most or all endpoints 104 connected to mBS 102 and/or scBS 1 18, the related network 100, and particularly PRACH, may be overloaded when the mass event resolves, e.g., power is returned. Additionally, network 100 may be unable to identify particular endpoints 104 that are involved in the mass event. When large numbers of endpoints 104 attempt to access the network simultaneously, the access channel including a RACH/PRACH, may be overloaded, if the PRACH becomes overloaded when, then messages sent from endpoints 104 attempting to reconnect to mBS 102 and/or scBS 1 18 may collide and some or most endpoints 104 may be unable to connect to network 100.

[01)52] T he PRACH may be a specific access channel used for PHY layer messages. Further, the PRACH may be based on a Zadoff-Chu (ZC) function. A ZC function may exhibit auto-correlation, cross-correlation and constant amplitude zero autocorrelation (CAZAC) properties. A ZC function may have a set number of total roots, Ν _& -,·, For example, in an LTE implementation, the ZC function may have eight hundred and thirty-nine roots or Nzc=839. The particular root for a message may be designated as "n." In operation, for example, if a particular endpoint 104 transmits over a PRACH with a root of five hundred and eleven, e.g., n ^::: 53 1 , then a correlation decoder on mBS 102 and/or scBS 1 18 may detect only noise during scanning unti l it reaches root five hundred and eleven where mBS 102 and/or scBS 1 1 8 may detect a voltage spike, or "needle" like waveform, that may indicate a message from that particular endpoint 104. Thus, PRACH protocol may identify the respective endpoint 104. Additionally, a cyclically time-shifted ZC root may exhibit the same autocorrelation properties as the main ZC root (Nz ). A time shift may be designated as Ncs.

[01)53] Additionally, in digital communications, such as communication over a air interface (e.g., a wireless network and/or network 100 of FIGURE 1) random access signature (also referred to as "'signatures") may be a sequence of randomly selected bit sequences out of a pool of known bit sequences included in random access subframes to synchronize endpoints 1.04 in time and frequency with mBS 102 and/or scBS 118, niBS 102 and/or scBS 1 18 may utilize or process random access signatures when receiving access transmission requests from endpoini 104, The pool of access sequences may be known to the endpoini, which may select randomly one of the random access signatures to transmit to the base station. Further, in one embodiment, one random access subframe (discussed with reference to FIGURE 3 below) may include up to sixty-four signatures, in some embodiments of the present disclosure, as endpoints 104 communicate with mBS 102, up to sixty-four random access signatures may be processed by mBS 102 and/or scBS 3 18 within one random access subframe. A set of random access signatures may be termed a "random access set" or a "signature set," and may correspond to one ZC root and/or one or more Nzc Ncs signatures in the case of scBS 1 18.

[0054] FIGURE 3 illustrates an example allocation 300 in a plurality of non-time- aiigned random access subframes as part of time-aligned resource blocks 302 utilized, by base stations located in the same vicinity, in accordance with one embodiment of the present disclosure, Resource blocks 302 of bandwidth operating on the same frequency may be re-used by one or multiple mBS 102 and/or scBS 1 18, Example allocation 300 may be understood to represent multiple resource blocks allocated in time and frequency domains for a group of three base stations located in the same vicinity. For example, a LTE channel bandwidth of twenty MHz may include one hundred resource blocks 302, In the example allocation 300, the middle resource blocks may be partially designated for PRACH access. For example, in a set of one hundred resource blocks, the central resource blocks (forty-seven through fifty-two) may be designated with priority for PRACH access until fully occupied by PRACH subframes. Each frame of the central resource blocks may be further divided into subframes that may correspond to a, certain time duration. For example, resource block 304 may have ten subframes numbered zero through nine, each subframe corresponding to one millisecond of time duration. Each subframe may be assigned a particular purpose, such as a random access subframe. A random access subframe may correspond to a data communication request (e.g., a request or transmission of a packet of data or other information) between endpoints 104 and mBS 102 and/or scBS 1 18.

[0055] In some embodiments of the present disclosure, certain subframes on die resource blocks designated for PRACH access may be designated for particular types of access. As an example, in allocation 300, scBS 1 19a may designate resource block 304 subframe three for PRACH access, and the remaining subfrarnes for standard data traffic. As another example, mBS 102 may designated resource block 306 subfrarnes zero, two, four, six, and eight for PRACH access and the remaining subfrarnes for standard data traffic. Further, scBS 1 18b may designate resource block 308 subframe one for PRACH access and the remaining subfrarnes for standard data traffic. In a co- channel OSC configuration (as discussed in detai l below with reference to FIGURE 6), in which all resource blocks modulate the same frequency carrier, PRACH subfrarnes may not be time aligned for all mBS 102 and scBSs 1 18. In this case, endpoints 104 attempting to access scBS 1 18a (resource block 304) on subframe three may interfere with a data transmission being received on subframe three of neighboring mBS 102 (subject to an interference path as discussed below with reference to FIGURE 5), shown as resource block 306. As another example, subframe three of resource block 306 may be allocated for user data traffic. In this case, a random access signal may be transmitted over subframe three of resource block 306 by an endpomt 104 intended for a neighboring base station (e.g., scBS 1 18a or 1 1 b), The random access signal may interfere with data signals received on the same subframe of resource block 304 by scBS 1 18b (e.g., subframe three) and may possibly render the data unusable. Accordingly, time alignment of PRACH subfrarnes may support, autocorrelation and cross correlation of a PRACH ZC function. Time alignment may enable simultaneous operation across the same random access subfrarnes as long as different sets of ZC roots or signatures are enabled.

(0056] FIGURE 4 illustrates an example allocation 400 in a plurality of time- aligned random access subfrarnes and resource blocks 402 utilized by base stations located in the same vicinity, in accordance with one embodiment of the present disclosure. Resource blocks 402 of bandwidth operating on the same frequency carrier may be shared by one or multiple mBS 102 and/or scBS 1 1 8. Example allocation 400 may be understood to represent multiple resource blocks, which may be time-aligned and may utilize the same intra-band frequency resources, and may be used simultaneously by base stations, such as, mBS 102 and/or scBS 1 18, located in the same vicinity, in some embodiments of the presen disclosure, resource block 404 for scBS 1 18a, resource block 406 for mBS 102, and resource block 408 for scBS 1 1 8b may all be time-aligned and may re-use the same infra-band frequency resources such that subframe two may be designated for PRACH access for each resource block 404, 406, and 408, Random access subframe alignment may avoid or mitigate the interference between random access and data subframes when received by a particular base station. Subframes for a particular type of access may be assigned statically or dynamically, Dynamic assignment may allow the subframes al located to PRACH access to change over time as configured by the network and may be based in part on the number of endpoints 104 per cell. The number of RACH messages may be monitored via a PRACH collision rate. As the PRACH collision rate increases, more subframes may be designated for PRACH access. Thus, in a network utilizing base stations on the same frequency carrier, PRACH subframes may be time-aligned for all mBS 102 and scBS 1 18 that may also re-use the same intra-band frequency resources.

[0057J FIGURE 5 illustrates an example configuration 500 of multiple mBSs 102 and PRACH immunity radius 502, in accordance with one embodiment of the present disclosure. Configuration 500 may include mBS 102a and mBS 102b. Each mBS 102a and 102b may have an associated cell 1 10a and 1 10b. respectively, in some embodiments of the present disclosure, multiple endpoints 104 may be located in each cell 1 10. In operation of the present example, when endpoint 104a accesses over the PRACH mBS 102a, the PRACH transmission may also reach mBS 102b via interference path 504. interference path 504 between endpoint 104a and mBS 102b may be termed the "PRACH interference path." in order to reduce or eliminate this interference, the path loss of interference path 504 should be greater than the related Ime-of-sight path loss able to trigger a signal on mBS 102b. if the loss of interference path 504 is not sufficient, a collision may occur when endpoint 104b accesses mBS 102b employing the same signature as endpoints 104a. In order for a collision to occur, endpoints 104a and 104b may need to utilize the same ZC root and Nzc/ Ncs signature within the same time aligned random access subframe. A collision may delay the access of endpoints 104a and 1 4b. immunity radius 502 may be the distance between a particular target mBS 102 and the closest edge of another ceil 1 10 that both employ the same random access signature set, e.g., Nzc/ cs signature, such that no PRACH interference may be created. For example, immunity radius 502 may be the distance needed between mBS 102b and the closest edge of cell 1 10a if mBS 102a and mBS 102b receive on the same random access subframe the same random access signature sets from endpoints 104a and 104b, respectively, without, causing any mutual access collisions.

[0058] FIGURE 6 illustrates an example of cluster 600 of cells 1 10 with multiple immuniiy radii, in accordance with one embodiment of the present disclosure. Cluster 600 may include a honeycomb cluster of hexagonal shaped cells 1 10. Each cell i 10 located in cluster 400 may be numbered one through ninety-three proceeding counterclockwise beginning with the center cell. Although not individually referenced, each numbered hexagonal shaped ceil 1 10 may include mBS 102 and one or more OSC 1 16, as illustrated with reference to FIGURE 1.

[0059] in some embodiments of the present disclosure, each cell 1 10 may be configured in a co-channel OSC topology such that each OSC 1 16 may utilize its own random access signature set. For simplicity, it may be assumed that each OSC 1 16 may have a radius of approximately one half of a kilometer. Each OSC 1 16 may employ one PRACH signature set, Depending on the number of OSCs 1 16 in each cell 1 10, the entire amount of random access signature sets may be used. Use of the entire pool of signature sets across a cluster of cells with an external radius smaller than the equivalent PRACH immunity radius may lead to PR ACM signature pool depletion and increased RACH message collisions, For example, the number of ZC roots may be calculated by first assuming that a single mBS 102 may require three ZC roots based on radius 402 of approximately three kilometers. Each scBS 1 18 may require one ZC root based on a radius of approximately one half of a kilometer. Thus, ten OSCs 1 16 located in ceil 1 10 may require ten ZC roots. Accordingly, the total amount of ZC roots for an approximately three kilometer cell 1 10 based on one mBS 102 and ten OSCs 1 16 may be thirteen. Additionally, cell 1 10 may be configured to employ a set of three co-located mBSs 102 in which each mBS 102 covers approximately one hundred and twenty degrees of the overall cell 1 10 coverage area. Therefore, the total required ZC roots per cell 1 10 may be thirty-nine. As noted previously, there may be a total of eight hundred and thirty-nine ZC roots. Thus, reuse of ZC roots may occur in a cluster grouping of approximately twenty-one cells 1 10, e.g., 21 X 39 = 819 ZC roots, which is less than eight-hundred and thirty-nine. |0060] In some embodiments of the present disclosure, cluster 600 may be divided into clusters, also called "tiers," as illustrated in FIGURE 6 that may be based in part on the immunity radius and/or the average number of OSC 1 16 per cell 1 10. One ^■• γ-t cluster 610 of cells 1 10 may correspond to a center cell 1 10, having a radius 602 of R, and directly adjacent similarly sized cells 1 10. Cluster 610 may have a total radius 604 of approximately 2R. In the current example, if radius 602 is approximately three kilometers, then the radius of cluster 610 may be approximately six kilometers, A second cluster 612 may have a radius 606 of approximately 3.7R, and a third cluster 614 may have a corresponding radius 608 of 8R,

[0061] In some embodiments of the present disclosure, for example, each cell 1 10 may include approximately sixteen OSCs 1 16 operating in a co-channel topology. The overall poo) of PRACH signatures, e.g. ZC roots, may be exhausted across cluster 612 of cells 1 10 with radius 606 or approximately 3.7R. In this example, the equivalent cluster of cells comprise approximately fourteen cells 3 10, e.g.. 19 signatures X 3 co-located mBS = 57 ZC roots and 839 max ZC roots / 57 ZC roots is approximately fourteen. Based on the following mathematical relationship:

MaxI T (839/57) = 14.

Thus, for sixteen OSCs 1 16 per cell 1 10 operating in a co-channel topology, the cell cluster size may be approximately fourteen. This ceil cluster size may equate to a PRACH immunity radius of approximately 3.7R, or radius 606.

[0062] As another example, each ceil 1 10 may include approximately thirty-two OSCs 1 16 operating in a co-channel topology. The overall pool of PRACH signatures, e.g. ZC roots, may be exhausted across cluster 610 of cells 1 10 with radius 604 or approximately 2R. in this example, the equivalent cluster of cells comprised approximately nine ceils \ 10, e.g., 35 signatures X 3 co-located mBS = 105 ZC roots and 839 max ZC roots / 105 ZC roots is approximately eight, based on the following relationship:

Max! T (839/105) = 8.

Thus, for thirty-two OSCs 1 16 per cell 1 30 operating in a co-channel topology, the ceil cluster size may be approximately eight. This ceil cluster size may equate to a PRACH immunity radius of approximately 2R, or radius 604,

[0063] in some embodiments of the present disclosure, reuse of the same ZC roots or signatures inside a PRACH Immunity Radius may degrade the ZC auto-correlation performance and may cause access delays for endpoints 104. Thus, the available amount of ZC roots may be depleted when co-channel OSC topology is employed due to the assignment of one ZC root per OSC in dense OSC topologies. The comparative 1 random access signature pool depletion rate in a co-channel configuration may he summarized as shown in the following table:

Table 1

As noted with reference to FIGURE 5, the PRACH immunity radius may represent the distance before a random access signature set may have to be reused within the same frequency channel for the same wireless protocol, For example, in a configuration, such as described in example B. above, the PRACH random access signature sets may require reuse after approximately twenty-five cells 1 10, Thus, the PRACH immunity radius may correspond to cluster 612 and radius 606 or approximately 3.7R. As another example, a configuration, such as described in example D, above, the PRACH signature sets may require reuse after only approximately eight cells 1 10. Thus, the PRACH immunity radius may correspond to cluster 610 and radius 604 or approximately 2R. Accordingly, in certain embodiments of the present disclosure, the random access signature set depletion rate may be influenced by the number of OSCs 116 installed per cell 1 10.

As discussed with reference to FIGURE 3, some embodiments of the present disclosure may include up to sixty-four PRACH signatures per random access subframe, As endpoints 104 communicate with mBS 102 and/or scBS 1 1 8, sixty-four signatures may be processed by mBS 102 and/or scBS 1 18 within one random access subframe. Further, a signature of a ZC function may be a specific time shift (Ncs) for a given ZC root. In some embodiments, a LTE PRACH sequence may be built by cyclically shifting a ZC sequence of prime length Nzc. defined as:

where:

u = the ZC index;

n = a particular root for a message; and

Nzc -839,

[0065] For a small ceil (e.g., OSC 1 16 having a radius of less than approximately 0.79 kilometers), one ZC root, may have up to sixty-four signatures. Under this assumption, signature logical indexes may be assigned to a PHY time cyclical shift ( cs) value. The signature logical index value may be further used to transport logical messages, The PHY time cyclical shift values (Ncs) associated with the signature logical indexes may be represented in the table below:

[0066] FIGURE 7A illustrates an example cell 1 10 cluster 700 with OSC 1 16 topology configured to optimize PRACH random access signature set allocation, in accordance with one embodiment of the present disclosure. In the current example, cluster 700 may include eight OSCs 1 16, e.g., OSCs 1 16a- h, OSCs 1 16a-h may share one PRACH ZC root. Each ZC root's cyclic shift may be associated with a logical index for a particular Ncs- The pool of time shifts of the same ZC root may be shared among all OSCs 1 16a-h covered by cell 1 10 without being re-used. Thus, instead of utilizing one ZC root for each OSC 1 16, all OSCs 1 16 within cell 1 10 may share one ZC root, if sixteen or less OSCs 1 16 within ceil 1 10, or two ZC roots if there are more than sixteen OSCs 1 16 within cell 1 10.

|0067j In some embodiments of the present disclosure, mBS 102 of cluster 700 may be given the designation Evolved Node~B 01 (eNBOl) and may have a radius of approximately 3.5 kilometers or approximately three kilometers. Each of scBS 1 18a— h within each OSCs 1 1 a--h, respectively, all located within the coverage of cell 1 10 may be given the designation eNB01.00-eNB01.07. respectively, and may have a radius of less than approximately 0.79 kilometers or approximately 0.5 kilometers. Additionally, in some embodiments, the sixty-four random access signatures employed by mBS 102 may be iogicaliy appended to the sixty-four signatures shared by scBSs 1 18a-h associated with OSCs 1 16a~h, respectively. Such an allocation may result in a total of one hundred and twenty eight logical indexes. Utilizing one ZC root (designated as "u +3") for scBS 1 18a--h and three ZC roots for mBS 102 (designated as "u," "u+1 ," and "u+2"), the following time shift, assignation may be employed:

[ΘΘ68] Further, in some embodiments of the present disclosure, when the amount of OSCs 1 1 6 per ceil 1 10 is greater than sixteen, the amount of random access signatures allocated for all OSCs 1 16 m be increased from sixty-four random access signatures to one hundred and twenty- eight ^' random access signatures. In this ease, the additional signatures may be incorporated by logically adding two ZC roots pool to the ZC root pool required by mBS 102 for cell 1 10. For example, sixty-four signatures may be employed by mBS 102 and an additional one hundred and twenty- eight signatures may be employed by OSCs 1 16 generating a total of one hundred and ninety-six random access signatures. In some embodiments of the present, disclosure, if the number of OSCs 1 16 per cell 1 10 is greater than thirty-two, then the number of ZC roots may be increased in the same manner as described above, e.g., by adding one ZC root per sixteen OSCs 1 16 and corresponding multiples of sixty-four signatures. The following table illustrates the possible immunity cluster size and corresponding PRACH immunity radius in a time aligned co-channel OSC 1.16 configuration by sharing of time shifted signatures of one or more ZC roots:

[Θ069] For example, in a cluster with sixteen OSCs 1 16 per cell 1 10, the cluster size of cells 1 10 that may be accommodated without having to reuse a PRACH signature set may be approximately sixty-nine cells 1 10. The corresponding PRACH immunity radius may be approximately 8R.

[007Θ] Thus, in some embodiments of the present disclosure, improvements may be realized in terms of the required PRACH immunity radius in a time aligned co- channel OSC 1 16 configuration by sharing of time shifted signatures of one or more ZC roots for two or more OSCs 1 16 (shown with reference to Table 4) in contrast to allocating one ZC root per mBS 102 and scBS 1 18 (shown with reference to Table 1 ). Accordingly, the following improvements may be realized with respect to an optimized allocation (shown with reference to Table 4) and a non-optimized allocation (shown with reference to Table 1): OSCs 116 N( [fii-o iimiaie

^!d C

per eel! PRJ iCM Imm i fitl . _| Improvement mmunit Radius

110 Radius

8 3.7 R 8.0 R X 2.16

16 3,7 R 8.0 R X 2.16

32 2.0 R 5.0 R X 2.5

Table 5

[0071] FIGURE 7B illustrates an example network 720 having a semi-static PRACH random access signature set scheduling configuration, in accordance with one embodiment of the present disclosure, In such a configuration, correlation may be made between complementary residential and business traffic patterns of two OSCs 1 16. As a result, part or all random access signature sets may be loaned from one OSC to another OSC during different time periods provided complementary traffic patterns are employed. For example, scBS 1 18b associated with OSC 1 16b may be configured within or proximate an enterprise and may be utilized primarily or exclusively by endpoints 104 associated with a business. Additionally. scBSs 1 18a and 1 18c associated with OSC 1 16a and 1 16c, respectively, may be configured within or proximate homes and may be utilized primarily or exclusively by endpoints 104 associated with a home and residential traffic. Many businesses may experience the majority of their network activity during the workday while many residential networks may experience the majority of their network activity in the evenings and on weekends. Allocation of signature sets may be scheduled such that the signature sets maybe allocated between residential and business networks on a semi-static basis to accommodate traffic peaks within each OSC 1 16. For example, during the workday, residential OSCs, such as OSCs 1 16a and 1 16c, each employing eight PRACH signatures, may loan four PRACH signatures each to a business OSC, such as OSC 1 16b as shown by directional arrows 724a and 724b, respectively. Therefore, OSC 1 16b may utilize a PRACH signature pool of twenty-four signatures during the workday (assuming an initial allocation of sixteen signatures), in the evenings and/or on weekends, signature sets may be allocated from OSC 1 16b to OSC 1 16a and 1 16c as shown by directional arrows 722a and 722b, respectively. For instance, OSC 1 16b may loan six signatures to each one of OSC 1 16a and 1 16c. Therefore, OSC 1 16a and OSC Ϊ 16c may employ fourteen signatures during evenings and weekends, while OSC 1 16b may operate with a reduced PRACH capacity of two signatures during the same time periods.

[0§72] FIGURE 8 illustrates a flow chart of an example method 800 for random access signature set optimization in a wireless network, such as network 600 of FIGURE 6, in accordance with one embodiment of the present disclosure. The steps of method 800 may be performed by various computer programs, models or any combination thereof, configured to simulate and design systems for random access signature set optimization employing OSC topology. The programs and models may include instructions stored on computer- readable medium, and operable to perform, when executed, one or more of the steps descr bed below. The computer-readable media may include any system, apparatus or device configured to store and retrieve programs or instructions such as a hard disk drive, a compact disc, flash memory or any other suitable device. The programs and models may be configured to direct a processor or other suitable unit to retrieve and execute the instructions from the computer-readable media. For illustrative purposes, method 800 is described with respect to network 600 of FIGURE 6: however, method 800 may be used for random access signature set optimization on any suitable network. Further, although discussed with reference to a network, portions or ail of method 800 may be executed by a component of network 100 including mBS 102, server 108, scBS 1 18, concentrator 130 and /or any other suitable component.

f$073] Method 800 may start and at step 805, a network, may designate resource blocks as PRACH resource blocks. F ^' or example, with reference to FIGURE 4, mBS 102 may designate resource blocks forty-seven through fifty-two for PRACH access. Method 800 may proceed to step 810,

[0074] At step 810, the network may designate random access subframes in the PRACH resource blocks as PRACH access subframes. For example, with reference to FIGURE 4. subframe two may be designated as PRACH access by mBS 102, scBS 1 18a, and scBS 1 18b. Subframe two may be time aligned across all base stations. Additionally, for a semi-static allocation, discussed with reference to FIGURE 7B, OSC 1 16 with an increased number of users that may demand a higher access capability, there may be PRACH subframes that may be assigned for particular times of the day or may be assigned dynamically as the number of endpoints 10 attempting access increases or decreases. Method 800 may proceed to step 820, [0075J At step 820, one or more ZC roots may be designated for mBS access. For example, a first set of three ZC roots, e.g., three sets of sixty-four random access signatures, may be designated for co-located mBS 102 within cell 1 10 with a radius of approximately three kilometers, as discussed with reference to FIGURE 7A. Method 800 may proceed to step 825.

[0076] At step 825, it may be determined if there are less than sixteen scBSs in a cell, If there are less than sixteen scBSs, then method 800 may proceed to step 830, At step 820, an additional ZC root, or random access signature set, may be defined for scBS transmissions. For example, a second set of sixty-four signatures may be designated for sharing among scBSs 1 1 8 within cell 1 10, as discussed with, reference to FIGURE 7A. Further, if at step 825 it is determined there are sixteen or more scBSs in a ceil, then method 800 may proceed to step 835 and two or more ZC roots, or random access signature sets, may be designated for sharing among scBSs 1 18 within the coverage area of cell 1 10. If there are more than thirty-one OSCs 1 16 per cell 1 10, three ZC roots may be shared among these OSCs 1 16. Method 800 may proceed to step 840.

|0077J At step 840, a set of ZC root cyclic shift (signatures) may be defined for each scBS, The definition may depend in part on the expected cell radius of the respective scBS. For example, with reference to FIGURE 7A and Tables 3 and 4, a ZC root cyclic shift may be associated with each OSC ί 16a— h. Method 800 may proceed to step 845.

j 0078| At step 845, the network may detect a transmission on the PRACH from an endpomt, such as endpoint 104. At step 850, the base station receiving the transmission may determine if the transmission is a RACH message, If the message is a RACH message, the base station may process the transmission on a subframe at step 855. For example, mBS 102 may process the RACH message on a designated PRACH access subframe, such as subframe two of resource block 406 shown in FIGURE 4. Method 800 may then proceed back to step 805. If the detected message is not a RACH message, then method 800 may proceed to step 860,

[0079} At step 860, the base station may determine if the message is a result of a PRACH collision. If the message is the result of a PRACH col lision, method 800 may return to step 805 and recalculate and re-designate the amount of PRACH resources required due to the increased network access demand, if the message is not the result of a PRACH collision, then the base station may receive the message on a data subframe, e.g., a subframe not designated for PRACH access at step 855. Method 800 may then proceed back to step 805,

[0080] All examples and conditional language recited herein are intended for pedagogical objects to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the ait, and are construed as being without limitation to such specifically recited examples and conditions. Although embodiments of the present inventions have been described in detail, it should be understood that various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the in vention.