Patent Publication Number: US-8995333-B2

Title: Synchronous interface for multi-radio coexistence manager

Description:
CROSS-REFERENCE 
     This application claims the benefit of U.S. Provisional Application Ser. No. 61/229,621, filed Jul. 29, 2009, and entitled “SYNCHRONOUS INTERFACE FOR MULTI-RADIO COEXISTENCE MANAGER,” the entirety of which is incorporated herein by reference. 
    
    
     BACKGROUND 
     I. Field 
     The present disclosure relates generally to wireless communications, and more specifically to managing coexistence between multiple radios utilized by respective devices in a wireless communication system. 
     II. Background 
     Wireless communication systems are widely deployed to provide various communication services; for instance, voice, video, packet data, broadcast, and messaging services can be provided via such wireless communication systems. These systems can be multiple-access systems that are capable of supporting communication for multiple terminals by sharing available system resources. Examples of such multiple-access systems 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 Single-Carrier FDMA (SC-FDMA) systems. 
     Generally, a wireless multiple-access communication system can include a number of radios to support communication with different wireless communication systems. Respective radios can operate on certain frequency channels or bands or can have respective predefined requirements. In order to manage communication via multiple radios and avoid collisions and/or interference between respective radios, it would be desirable to implement mechanisms to coordinate between respective radios that are in collision (e.g., radios configured such that their mutual operation would cause significant interference on at least one of the radios). Further, it would be desirable to implement bus structures and/or other means for facilitating communication between such mechanisms and respective radio endpoints that leverage such mechanisms. 
     SUMMARY 
     The following presents a simplified summary of various aspects of the claimed subject matter 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 nor delineate the scope of such aspects. Its sole purpose is to present some concepts of the disclosed aspects in a simplified form as a prelude to the more detailed description that is presented later. 
     According to an aspect, a method is described herein. The method can comprise identifying respective managed endpoints associated with respective potentially conflicting radio technologies and a multi-radio coexistence platform associated with the respective managed endpoints and maintaining a bus system that communicatively connects the respective managed endpoints to the multi-radio coexistence platform, wherein the bus system comprises one or more buses operating in a synchronous manner. 
     A second aspect relates to an apparatus operable in a wireless communication system. The apparatus can comprise respective managed endpoints associated with a set of potentially conflicting radio technologies; a coexistence manager (CxM) that facilitates coexistence between the respective managed endpoints; and a bus system that communicatively connects the respective managed endpoints to the CxM, wherein the bus system comprises one or more buses operating in a synchronous manner. 
     A third aspect relates to an apparatus, which can comprise means for identifying respective endpoints corresponding to a set of radio technologies and an application platform that manages coexistence between the set of radio technologies and their corresponding endpoints and means for maintaining a system of one or more buses operating in a synchronous manner that facilitate communication between the respective endpoints and the application platform. 
     A fourth aspect described herein relates to a computer program product, which can include a computer-readable medium that comprises code for causing a computer to identify respective endpoints corresponding to a set of radio technologies and an application platform that manages coexistence between the set of radio technologies and their corresponding endpoints and code for causing a computer to maintain a system of one or more buses operating in a synchronous manner that facilitate communication between the respective endpoints and the application platform. 
     To the accomplishment of the foregoing and related ends, one or more aspects of the claimed subject matter 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 aspects of the claimed subject matter. These aspects are indicative, however, of but a few of the various ways in which the principles of the claimed subject matter can be employed. Further, the disclosed aspects are intended to include all such aspects and their equivalents. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of an example wireless communication environment in which various aspects described herein can function. 
         FIG. 2  is a block diagram of an example wireless device that can be operable to manage coexistence between respective radios in an associated wireless communication system in accordance with various aspects. 
         FIG. 3  is a block diagram of an example multi-radio coexistence management system that can be operable to implement various aspects described herein. 
         FIG. 4  is a block diagram of a system that facilitates management of a synchronous bus interface between a multi-radio coexistence manager (CxM) and respective CxM-managed endpoints in accordance with various aspects. 
         FIG. 5  is a block diagram that illustrates a multi-radio coexistence solution that can be utilized for management of respective endpoints. 
         FIGS. 6-7  are block diagrams that illustrate respective improved multi-radio coexistence solutions that leverage respective synchronous buses and/or bus interfaces in accordance with various aspects. 
         FIG. 8  is a block diagram of a system that facilitates use of a synchronous bus for communication between a CxM and respective CxM-managed endpoints in accordance with various aspects. 
         FIG. 9  illustrates operation of one or more example synchronous CxM buses in time in accordance with various aspects. 
         FIGS. 10-11  illustrate respective example multi-radio coexistence implementations that can leverage various aspects described herein. 
         FIGS. 12-13  are flow diagrams of respective methodologies for leveraging a substantially synchronous bus system to facilitate multi-radio coexistence for a set of managed endpoints. 
         FIG. 14  is a block diagram of an apparatus that facilitates implementation and management of a synchronous bus architecture for multi-radio coexistence management within a communication system. 
     
    
    
     DETAILED DESCRIPTION 
     Various aspects of the claimed subject matter are now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. 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. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing one or more aspects. 
     Furthermore, various aspects are described herein in connection with a wireless terminal and/or a base station. A wireless terminal can refer to a device providing voice and/or data connectivity to a user. A wireless terminal can be connected to a computing device such as a laptop computer or desktop computer, or it can be a self contained device such as a personal digital assistant (PDA). A wireless terminal can also be called a system, a subscriber unit, a subscriber station, mobile station, mobile, remote station, access point, remote terminal, access terminal, user terminal, user agent, user device, or user equipment (UE). A wireless terminal can be a subscriber station, wireless device, cellular telephone, PCS telephone, 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, or other processing device connected to a wireless modem. A base station (e.g., access point or Node B) can refer to a device in an access network that communicates over the air-interface, through one or more sectors, with wireless terminals. The base station can act as a router between the wireless terminal and the rest of the access network, which can include an Internet Protocol (IP) network, by converting received air-interface frames to IP packets. The base station also coordinates management of attributes for the air interface. 
     Moreover, it can be appreciated that various illustrative logical blocks, modules, circuits, algorithm steps, etc., described in connection with the disclosure herein can be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps are described herein generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans can implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure. 
     The various illustrative logical blocks, modules, and circuits described in connection with the disclosure herein can additionally or alternatively 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 can be a microprocessor, or alternatively the processor can be any conventional processor, controller, microcontroller, state machine, or the like. A processor can 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. 
     Furthermore, various functions of one or more example embodiments described herein can be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions can be stored on or transmitted as one or more instructions or code on a computer-readable medium. Computer-readable media can include both computer storage media and communication media. Communication media can include any medium that facilitates transfer of a computer program from one place to another. Likewise, storage media can include any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM, digital versatile disc (DVD), blu-ray disc, or other optical disk storage, magnetic disk storage or other magnetic storage devices, and/or any other medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer or a general-purpose or special-purpose processor. Further, any connection is properly 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/or microwave, then such means are intended to be included in the definition of medium. “Disk” and “disc,” as used herein, includes compact disc (CD), laser disc, optical disc, DVD, floppy disk, and blu-ray disc, where “disks” generally reproduce data magnetically while “discs” reproduce data optically (e.g., with lasers). Combinations of the above can also be included within the scope of computer-readable media. 
     Referring now to the drawings,  FIG. 1  illustrates an example wireless communication environment  100  in which various aspects described herein can function. Wireless communication environment  100  can include a wireless device  110 , which can be capable of communicating with multiple communication systems. These systems can include, for example, one or more cellular systems  120  and/or  130 , one or more wireless local area network (WLAN) systems  140  and/or  150 , one or more wireless personal area network (WPAN) systems  160 , one or more broadcast systems  170 , one or more satellite positioning systems  180 , other systems not shown in  FIG. 1 , or any combination thereof. It should be appreciated that in the following description the terms “network” and “system” are often used interchangeably. 
     Cellular systems  120  and  130  can each be a CDMA, TDMA, FDMA, OFDMA, SC-FDMA, or other suitable system. A CDMA system can implement a radio technology such as Universal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. Moreover, cdma2000 covers IS-2000 (CDMA2000 1X), IS-95 and IS-856 (HRPD) standards. A TDMA system can implement a radio technology such as Global System for Mobile Communications (GSM), Digital Advanced Mobile Phone System (D-AMPS), etc. An OFDMA system can implement a radio technology such as Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), 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) and LTE-Advanced (LTE-A) are new releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described in documents from an organization named “3rd Generation Partnership Project” (3GPP). cdma2000 and UMB are described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2). In an aspect, cellular system  120  can include a number of base stations  122 , which can support bi-directional communication for wireless devices within their coverage. Similarly, cellular system  130  can include a number of base stations  132  that can support bi-directional communication for wireless devices within their coverage. 
     WLAN systems  140  and  150  can respectively implement radio technologies such as IEEE 802.11 (Wi-Fi), Hiperlan, etc. WLAN system  140  can include one or more access points  142  that can support bi-directional communication. Similarly, WLAN system  150  can include one or more access points  152  that can support bi-directional communication. WPAN system  160  can implement a radio technology such as IEEE 802.15.1 (Bluetooth), IEEE 802.15.4 (Zigbee), etc. Further, WPAN system  160  can support bi-directional communication for various devices such as wireless device  110 , a headset  162 , a computer  164 , a mouse  166 , or the like. 
     Broadcast system  170  can be a television (TV) broadcast system, a frequency modulation (FM) broadcast system, a digital broadcast system, etc. A digital broadcast system can implement a radio technology such as MediaFLO™, Digital Video Broadcasting for Handhelds (DVB-H), Integrated Services Digital Broadcasting for Terrestrial Television Broadcasting (ISDB-T), or the like. Further, broadcast system  170  can include one or more broadcast stations  172  that can support one-way communication. 
     Satellite positioning system  180  can be the United States Global Positioning System (GPS), the European Galileo system, the Russian GLONASS system, the Quasi-Zenith Satellite System (QZSS) over Japan, the Indian Regional Navigational Satellite System (IRNSS) over India, the Beidou system over China, and/or any other suitable system. Further, satellite positioning system  180  can include a number of satellites  182  that transmit signals used for position determination. 
     In an aspect, wireless device  110  can be stationary or mobile and can also be referred to as a user equipment (UE), a mobile station, a mobile equipment, a terminal, an access terminal, a subscriber unit, a station, etc. Wireless device  110  can be a cellular phone, a personal digital assistant (PDA), a wireless modem, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, etc. In addition, wireless device  110  can engage in two-way communication with cellular system  120  and/or  130 , WLAN system  140  and/or  150 , devices within WPAN system  160 , and/or any other suitable system(s) and/or device(s). Wireless device  110  can additionally or alternatively receive signals from broadcast system  170  and/or satellite positioning system  180 . In general, it can be appreciated that wireless device  110  can communicate with any number of systems at any given moment. 
     Turning next to  FIG. 2 , a block diagram is provided that illustrates an example design for a multi-radio wireless device  200 . As  FIG. 2  illustrates, wireless device  200  can include N radios  220   a  through  220   n , which can be coupled to N antennas  210   a  through  210   n , respectively, where N can be any integer value. It should be appreciated, however, that respective radios  220  can be coupled to any number of antennas  210  and that multiple radios  220  can also share a given antenna  210 . 
     In general, a radio  220  can be a unit that radiates or emits energy in an electromagnetic spectrum, receives energy in an electromagnetic spectrum, or generates energy that propagates via conductive means. By way of example, a radio  220  can be a unit that transmits a signal to a system or a device or a unit that receives signals from a system or device. Accordingly, it can be appreciated that a radio  220  can be utilized to support wireless communication. In another example, a radio  220  can also be a unit (e.g., a screen on a computer, a circuit board, etc.) that emits noise, which can impact the performance of other radios. Accordingly, it can be further appreciated that a radio  220  can also be a unit that emits noise and interference without supporting wireless communication. 
     In accordance with one aspect, respective radios  220  can support communication with one or more systems. Multiple radios  220  can additionally or alternatively be used for a given system, e.g., to transmit or receive on different frequency bands (e.g., cellular and PCS bands). 
     In accordance with another aspect, a digital processor  230  can be coupled to radios  220   a  through  220   n  and can perform various functions, such as processing for data being transmitted or received via radios  220 . The processing for each radio  220  can be dependent on the radio technology supported by that radio and can include encryption, encoding, modulation, etc., for a transmitter; demodulation, decoding, decryption, etc., for a receiver, or the like. In one example, digital processor  230  can include a coexistence manager (CxM)  240  that can control the operation of radios  220  in order to improve the performance of wireless device  200  as generally described herein. 
     For simplicity, digital processor  230  is shown in  FIG. 2  as a single processor. However, it should be appreciated that digital processor  230  can comprise any number of processors, controllers, memories, etc. In one example, a controller/processor  250  can direct the operation of various units within wireless device  200 . Additionally or alternatively, a memory  252  can be used to store program codes and data for wireless device  200 . Digital processor  230 , controller/processor  250 , and memory  252  can be implemented on one or more integrated circuits (ICs), application specific integrated circuits (ASICs), etc. By way of specific, non-limiting example, digital processor  230  can be implemented on a Mobile Station Modem (MSM) ASIC. 
     In accordance with one aspect, respective radios  220  can impact and/or be impacted by respective other radios  220  through various mechanisms (e.g., radiative, conductive, and/or other interference mechanisms). In some cases, such interference can render some event combinations impossible or otherwise impractical to occur across different radios simultaneously. Accordingly, it can be appreciated that a substantially optimal decision on a given radio  220  (e.g., a decision regarding whether to provide a negative acknowledgement (NACK) or reduced transmit power for a WLAN transmitter radio, etc.) can in some cases depend on the status of respective other associated radios  220 . Accordingly, CxM  240  can handle management of radios in the presence of potential conflicts without requiring piece-wise solutions for each pair of mechanisms. 
     Turning next to  FIG. 3 , a block diagram of an example system  300  for multi-radio coexistence management that can be operable to implement various aspects described herein is illustrated. As shown in  FIG. 3 , system  300  can include a CxM  240 , which can manage respective CxM endpoints  330  (e.g., radios  220 , antennas, power amplifiers (PAs), filters, mixers, modems, etc.) as generally described herein. In accordance with one aspect, CxM  240  can be coupled to and/or otherwise leverage the functionality of a connection manager (CnM)  310 , a CxM control entity  320 , and/or other suitable components. In accordance with one aspect, CxM  240 , together with CnM  310  and CxM control entity  320 , can operate collectively as a radio frequency (RF) coexistence platform for one or more CxM endpoints  330 . 
     In one example, CnM  310  can facilitate connectivity of respective CxM endpoints  330  based on information obtained from CxM  240 . For example, CnM  310  can be utilized to assign an optimal set of resources for optimal concurrent use by applications associated by respective CxM endpoints  330 . In another example, CxM control entity  320  can be any suitable integrated circuit, subsystem, or combination thereof (e.g., one or more processors, state machines, etc.) operable to configure operation of CxM  240  and/or respective buses managed and/or otherwise operated by CxM  240  as generally described herein. Additionally or alternatively, CxM control entity  320  can act as a peripheral subsystem, thereby improving peripheral throughput and system concurrency associated with system  300 , by decoupling peripheral operations from a main host processor or the like and/or by performing other suitable actions. 
     In accordance with another aspect, system  300  and the components illustrated therein can act independently and/or with the aid of any other suitable module(s) to implement various aspects of the functionality described herein, and/or any other suitable functionality, in the context of any appropriate application(s), operating mode(s), or the like. However, it should be appreciated that the implementations illustrated and described herein are intended merely as non-limiting example multi-radio coexistence implementations and that, unless explicitly stated otherwise, the claimed subject matter is not intended to be limited to any specific implementation(s). 
     Turning next to  FIG. 4 , a system  400  that facilitates management of a synchronous bus interface between a multi-radio CxM  240  and respective CxM-managed endpoints  430  is illustrated. As shown in  FIG. 4 , a CxM  240  can be provided for a set of CxM-managed endpoints  430  (e.g., radios, antennas, PAs, filters, mixers, modems, etc.). In one example, a bus system that includes one or more synchronous buses  410  and zero or more supplemental buses  420  can be utilized within system  400  to communicatively connect respective CxM endpoints  430  and/or other suitable managed endpoints to a multi-radio coexistence platform that includes CxM  240 . 
     In accordance with one aspect, respective synchronous buses  410  in system  400  can operate according to a synchronous protocol (e.g., as controlled by a synchronous bus manager  440  and/or other suitable means), thereby facilitating a synchronous interface design for multi-radio coexistence management. In one example, such a design can facilitate coordination and allocation system resources that encompass a solution space including, for example, RF/Antenna, Baseband, Protocol, and/or other suitable elements. 
     In accordance with another aspect, it can be appreciated that communication systems with multiple radios in a close environment can create substantial operational issues. Such issues can present, for example, under conditions of concurrency (e.g., wherein multiple radios operate simultaneously), as radio coexistence issues can arise in such conditions that can, in turn, result in poor user experience. Further, it can be appreciated that the problem of communication between multiple radios operating on a given common platform can be difficult due to the heterogeneity of respective radio technologies (e.g., based on factors such as physical interfaces, protocol stack, operating system, or the like). 
     Conventionally, individualized solutions such as packet traffic arbitration (PTA) for Bluetooth (BT) and Wireless Local Area Network (WLAN) technologies are employed to facilitate radio coexistence. However, it can be appreciated that such conventional solutions are piecewise in nature and, as such, do not cover multiple radios. Further, it can be appreciated that existing multi-radio management techniques utilize proprietary and diverse interfaces, which as a result require greater pin counts, higher power and area, higher overall complexity, and the like. Thus, in accordance with various aspects described herein, CxM  240  and system  400  can be utilized to provide a uniform, universal, and easily extendable multi-radio coexistence solution, in combination with a synchronous bus interface that can be utilized to mitigate at least the above shortcomings of conventional solutions. 
     As illustrated by system  400 , one or more buses operating according to a synchronous protocol (e.g., synchronous bus(es)  410 ) can be utilized to facilitate communication between CxM  240  and respective managed endpoints of CxM  240 , such as CxM endpoints  430 . In one example, CxM endpoints can correspond to various components of any suitable radio access technology (RAT). Examples of RATs that can correspond to CxM endpoints  430  include, but are not limited to, 3GPP LTE, Forward Link Only (FLO), BT, WLAN, UMTS, or the like. 
     As further shown in  FIG. 4 , one or more elements of system  400 , such as CxM  240 , CxM endpoint(s)  430 , synchronous bus(es)  410 , or the like, can be coupled to and further leverage one or more supplemental buses  420  for communication within system  400 . In one example, supplemental bus(es)  420  in system  400  can operate according to any suitable bus protocol, such as a synchronous protocol, an asynchronous protocol, and/or any other suitable protocol or combination of suitable protocols. In another example, one or more supplemental buses  420  can be reprogrammable for operation according to a plurality of operating modes, such as a synchronous mode, an asynchronous mode, and/or any other suitable mode(s). To these ends, one or more supplemental bus(es)  420  can be associated with a bus reprogramming module  450  and/or appropriate modules. While not shown in system  400 , one or more synchronous buses  410  can in some cases additionally or alternatively be capable of reprogramming for operation according to a non-synchronous protocol for a definite or indefinite period of time (e.g., for at least one decision unit in time and/or any other suitable time interval). 
     As noted above, it can be appreciated that an increasing number of radios in different configurations and technologies are being connected to portable devices, platforms, system-on-a-chip (SOC) implementations, and the like, in different configurations and technologies. Existing platforms can be utilized to provide coexistence between two interfering frequency bands by, for example, using specific proprietary bus structures and/or software. An example of this is illustrated in system  500  in  FIG. 5 , wherein respective proprietary buses are utilized to coordinate between respective pairs of radios  220  and/or other radio technology-related endpoints associated with an application platform  510 . As illustrated herein, application platform  510  can include one or more internal or external application processors and/or other suitable means for handling applications associated with radios  220  and/or other endpoints associated with application platform  510 . 
     However, as the number of technologies utilized by devices increases, more and different communication stacks have to coexist, each requiring special attention in the SOC to do no ultimate harm to the system and its related user experience. Accordingly, it can be appreciated that improved high-level operating system (HLOS), application platform, and modem developments are inhibited without dedicated solutions for an overall combination of radios and/or other endpoints connected to a given platform. Thus, system  400  and CxM  240  as described above can operate to provide manageability and coexistence of different radios and/or other endpoints in real time and without extra burden on existing interfaces, software, HLOS, and the like. Further, the various aspects provided herein facilitate a complete, flexible, and scalable solution for multi-radio coexistence without requiring significant re-invention of bus structures or protocol schemes. 
     Thus, in contrast to the piecewise coexistence solution shown in diagram  500 , a synchronous bus structure as illustrated by system  600  in  FIG. 6  can be utilized by a CxM and/or another suitable management entity to connect distinct communication devices (e.g., radios, filters, PAs, etc.) of different radio technologies in a simplified manner. For example, a synchronous multi drop bus  602  and/or another suitable bus structure can be utilized for substantially all radios  220  and/or other radio technology-based endpoints associated with a given application platform  510  without requiring proprietary piecewise coexistence implementations. Accordingly, as shown in system  600 , a synchronous bus and its corresponding protocol can be made independent and agnostic from existing modem-level, radio-level, or other lower level software and/or hardware implementations. Further, it can be appreciated that as synchronous multi drop bus  602  operates in a synchronous manner, system  600  can operate via synchronous multi drop bus  602  with awareness of system latency. 
     As illustrated by  FIG. 6 , a single bus, such as a synchronous multi drop bus  602  or the like, can be utilized to provide universal connectivity between a set of radios  220  and/or other endpoints and an application platform  510 . Alternatively, as shown in system  700  in  FIG. 7 , functionality of a synchronous multi drop bus  602  or the like can be realized by way of one or more external buses  712 - 714  in combination with one or more internal buses  724  located within application platform  510  and/or other integrated circuits and/or SOCs implemented within system  700 . For example, as shown in  FIG. 7 , application platform  510  and/or another suitable integrated circuit can have implemented thereon one or more internal buses  722 - 724  and at least one managed endpoint (e.g., a radio  220  and/or another suitable endpoint). Accordingly, a bus system can be maintained that communicatively connects application platform  510  and/or another suitable integrated circuit and respective additional portions of a multi-radio coexistence platform such that respective managed endpoints implemented on the integrated circuit are coupled to the bus system via the one or more internal buses implemented on the integrated circuit. 
     Thus, as shown by systems  600  and  700 , it can be appreciated that a synchronous bus system can be implemented and maintained in order to mitigate the shortcomings of traditional piecewise interfaces between respective radio technologies in a multi-radio device. The bus system can be implemented as a single bus that connects substantially all endpoints, as shown in system  600 , and/or as a plurality of discrete external and/or on-chip buses that collectively connect substantially all endpoints, as shown in system  700 . 
     In accordance with one aspect, respective external buses in system  600  and/or system  700  can be implemented as a multi drop bus, which can consist of one or more wires that are connected to the same pins and/or other connection points on a given set of associated integrated circuits (e.g., associated with radios  220 , other endpoints, and/or application platform  510 ). Additionally or alternatively, as shown in system  700 , respective external buses  712 - 714  can interface with one or more internal buses  722 - 724  associated with respective integrated circuits associated with system  700 . In one example, an internal bus  722  and/or  724  associated with an integrated circuit that interfaces with an external bus  712  and/or  714  can utilize a common bit width with the corresponding external bus  712  and/or  714  or a differing bit width. Further, it can be appreciated that bit widths associated with any endpoint(s) in system  600  and/or system  700  can be uniform and/or varying in any suitable manner. 
     With reference to systems  600  and  700 , it can be appreciated that synchronous multi drop bus  602  in system  600 , as well as the collective external buses  712 - 714  and internal buses  722 - 724  in system  700 , provide a unified bus structure, in contrast to previous implementations which have utilized proprietary and diverse interfaces. In one example, bus structures utilized by system  600  and/or system  700  can provide a shared multi-drop interface, thereby providing pin savings, lower power and/or lower area silicon implementations, and/or other suitable benefits. Further, it can be appreciated that systems  600  and  700  provide a synchronous interface, thereby providing controlled latency as required by various coexistence management schemes. In another example, bus structures utilized by system  600  and/or system  700  can be made OS/HLOS agnostic by virtue of operating at lower layers. In an additional example, an interface as illustrated by system  600  and/or system  700  can be made modem protocol stack agnostic within a multi-radio environment, thereby simplifying platform integration. In a further example, a multi-radio coexistence system as illustrated by  FIG. 6  and/or  FIG. 7  can be implemented in software or in hardware, thereby enabling its application to different types of platforms and/or products depending on the performance and complexity desired. 
     In one example, implementation of the interfaces shown in  FIGS. 6-7  can be achieved wholly or in part via standard bus structures and/or transport protocols, such as SLIMbus, RF front-end (RFFE) implementations, or the like, to minimize the adaptation barrier for platform implementation. Further, a common bus can be utilized to avoid scattered coexistence managers conventionally necessary for respective individual radio pairs. In addition, by providing centralized connectivity between substantially all associated radio technologies, a bus system as implemented by system  600  and/or system  700  can be operable to avoid platform incompatibility, connectivity partitioning, and/or other similar issues. 
     In accordance with one aspect, an isochronous and/or synchronous protocol as used herein can introduce real time capability (e.g., with a maximum latency on the order of 150 μs) and re-configurability on demand to conceive changes of connected devices and their policies after a period of data evaluation for respective participants. Further, an isochronous or synchronous bus and/or protocol as provided herein can be utilized to allow a broadcast mechanism to reach all connected devices on a bus simultaneously. In a further aspect as illustrated by  FIGS. 6-7 , a multi-drop topology can be utilized by a bus system as provided herein to provide a low pin count, a low power infrastructure, and/or other benefits. 
     It can be appreciated that a multi-radio coexistence interface as shown in  FIG. 6  and/or  FIG. 7  can be implemented in hardware, in software (e.g., as an emulation of hardware), or a combination of hardware and software. Thus, by way of non-limiting example, various structures as described herein can be implemented as a “direct hardware” implementation with zero or minimum required software involvement. 
     Referring next to  FIG. 8 , a block diagram of a system  800  that facilitates use of a synchronous bus for communication between a CxM  240  and respective CxM-managed endpoints in accordance with various aspects is illustrated. As shown in system  800 , devices and/or other entities associated with respective radio technologies  810  can be coupled to a CxM  240  via a CxM bus  830 . In accordance with one aspect, CxM bus  830  can be managed by a synchronous bus host  840  and/or other suitable means, thereby facilitating a synchronous connection between CxM  240  and connected radio technologies (e.g., via RF components  812 , baseband components  814 , antennas  816 , PAs  818 , filters  820 , or the like). In one example, system  800  can utilize an interface that is extendable to any suitable number of devices and/or associated radio technologies  810 . By way of specific, non-limiting example, CxM bus can support a predetermined number N of devices (e.g., 10 devices, etc.) and can be extendable to multiples xN of devices connectable to the platform by utilizing additional instances of CxM bus  830 . In another specific, non-limiting example, CxM bus  830  can utilize any suitable number of pins and any suitable corresponding bit width—for example, CxM bus  830  can leverage a two-pin solution, a (2xX) pin solution, or the like. 
     In accordance with one aspect, CxM bus  830  can be a radio-, modem-, and/or coexistence requirement-agnostic synchronous bus, which can be centralized in any suitable application processor or control unit associated with a mobile platform. Further, CxM bus  830  can be utilized as a hardware replacement for software coexistence management in some cases (e.g., if no real time capability is required). 
     In accordance with another aspect, CxM bus  830  can utilize a multi-drop structure and/or any other suitable structure for connecting substantially all existing radios, antennas, PAs, filters/mixers, or the like associated with radio technologies  810  with a synchronous protocol. Accordingly, CxM bus  830  can be utilized as a common, flexible, robust, and cost-effective design to interface substantially all possible combinations of radios, antennas, PAs, filters/mixers, etc., of any suitable radio technology  810  or combination thereof (e.g., point to point (P2P), Circuit Switch, internet protocol (IP), etc.). In one example, CxM bus  830  and respective connected devices or modules can be controlled by a central CxM host to enable seamless (e.g., no loss of data) coexistence management, re-configurability of coexistence policies, on-demand priority adaptation, or the like, as well as keeping full compliance to a synchronous bus architecture. 
     In accordance with a further aspect, system  800  can mitigate conventional problems experienced by portable devices in managing coexistence of different radios, networks, and protocol stack technologies via a configurable, power-aware bus architecture and its synchronous protocol. Additionally or alternatively, various mechanisms as described herein can mitigate conventional problems associated with radio synchronization. 
     In one example, a CxM mechanism as shown in system  800  can utilize a hardware bus structure and/or mimic the structure as a pure software solution by, for example, loosening hard real time requirements/requests. For example, as generally described above, the structure and/or implementation of CxM bus  830  can vary outside and/or within various integrated circuits, SOCs, and/or other components that comprise system  800 . In particular, an external bus utilized to connect respective integrated circuits in system  800  can be configured to interface with internal bus structures on respective integrated circuits such as an advanced extensible interface (AXI) bus, an advanced high-performance bus (AHB), or the like, thereby facilitating the use of buses having differing and potentially higher bit widths within respective integrated circuits. Additionally or alternatively, external buses utilized to interface with respective integrated circuits can be scalable to varying degrees within system  800 . In a further example, a bus structure as illustrated by system  800  and/or other bus structures as described herein can allow coexistence management with full QoS, minimum latency, low pin count (e.g., 2 pins), and/or other benefits. 
     By way of specific example, various solutions can be implemented for synchronous decision unit (DU) transport to respective devices connected to CxM bus  830 . These solutions can include, for example, interleaved transport, chronological transport, or the like. By way of further non-limiting example, CxM bus  830  can be implemented at least in part via an existing Mobile Industry Processor Interface (MIPI)-based standard SLIMbus structure and/or any other suitable structure. For example, a 2-pin SLIMbus structure can be utilized to implement at least a portion of CxM bus  830  according to one or more predefined and/or proprietary synchronous SLIMbus protocols. Alternatively, other existing bus structures, such as RF front end (RFFE) implementations, could be utilized. 
     Turning next to  FIG. 9 , a diagram  900  is provided that illustrates operation of one or more example synchronous CxM buses in time in accordance with various aspects. In one example, a CxM and/or related radios can operate according to a timeline divided into DUs in time, which can be any suitable uniform or non-uniform length (e.g., 80 μs). By way of specific example, a DU can be divided into respective phases, such as a notification phase (e.g., 40 μs) where various radios send notifications of imminent events, an evaluation phase (e.g., 20 μs) where notifications are processed, a response phase (e.g., 20 μs) where responses to notifications received in the notification phase are provided based on the results of the evaluation phase, or the like. It should be appreciated, however, that diagram  900  is provided for illustration and that various multi-radio coexistence implementations as described herein can utilize any suitable timing scheme. Further, while a set of ten notifications (e.g., from ten distinct endpoints) is illustrated on diagram  900 , the various aspects herein are not intended to be limited to any specific number of devices and/or associated notifications. 
     In accordance with one aspect, diagram  900  illustrates respective mechanisms for minimum connection capability of multiple (e.g., 10) endpoints. It should be appreciated, however, that the mechanisms illustrated by diagram  902  are not intended to be limited to a given number of endpoints. Initially, a programmable message can be utilized for data and/or control signaling, which can utilize a data structure such as that shown in diagram  900 . By way of specific, non-limiting example corresponding to diagram  900 , a maximum P2P (e.g., Notification Period) data bit width can be 72 bits, a maximum P2P (e.g., Notification Period for each connected device) for each device can be between 4 and 5 μs, a maximum broadcast (e.g., Response) data bit width can be 320 bits, a maximum broadcast (e.g., Response Period) data period associated with each DU can be 20 μs, a maximum CxM evaluation period for each DU can be 20 μs, and a maximum latency can be 150 μs. 
     In accordance with another aspect, synchronous buses for multi-radio coexistence implemented as described herein can be utilized to facilitate communication of notifications and responses as shown in diagram  900 . For example, at least one bus operating in a synchronous manner can be maintained to communicatively connect at least one managed endpoint to an associated multi-radio coexistence platform, collect notifications for the multi-radio coexistence platform from the at least one managed endpoint, and facilitate conveyance of coexistence commands from the multi-radio coexistence platform to the at least one managed endpoint. More particularly, the bus can facilitate collection of notifications for the multi-radio coexistence platform from the at least one managed endpoint at a first time interval (e.g., a notification period), await processing of the notifications by the multi-radio coexistence platform at a second time interval subsequent to the first time interval (e.g., an evaluation period), and facilitate conveyance of coexistence commands from the multi-radio coexistence platform to the at least one managed endpoint at a third time interval subsequent to the second time interval (e.g., a response period). 
     In accordance with a further aspect, operation of a multi-radio coexistence bus system in time as shown by diagram  900  can be implemented for a single bus operating in a synchronous manner or multiple such buses. For example, multiple buses operating according to the timeline shown in diagram  900  can be implemented in parallel by a coexistence platform to facilitate receipt of notifications and/or conveyance of responses for an expanded set of devices. Additionally or alternatively, multiple buses can be implemented in a multi-radio system to provide communication between respective subsets of radio technologies in a uniform manner. 
     With reference now to  FIGS. 10-11 , respective diagrams  1000 - 1100  that illustrate example multi-radio coexistence implementations that can leverage various aspects described herein are provided. It should be appreciated that diagrams  1000 - 1100  are provided merely as examples of bus implementations that can be utilized in accordance with various aspects described herein and respective radio technologies that can be managed using such bus implementations. Further, unless explicitly stated otherwise, it is to be appreciated that the claimed subject matter is not intended to be limited to any specific implementation(s) or specific endpoint(s). 
     As illustrated first in diagram  1000  in  FIG. 10 , a 2-wire bus can be utilized to couple antennas, RF components, baseband (BB) components, and/or other endpoints associated with respective radio technologies to an application platform that provides multi-radio coexistence functionality for the respective endpoints. As further shown in diagram  1000 , the application platform can provide host functionality to facilitate operation of the bus in a synchronous manner. Further, diagram  1000  illustrates that one or more optional power management ICs (PMICs) can be coupled to the application platform and/or its managed endpoints via the bus. 
     Next, diagram  1100  in  FIG. 11  illustrates an implementation wherein respective radio technologies can utilize a set of four broadcast ports (BC 1  through BC 4 ) as well as an additional port for data (Pn). Further, the application platform is implemented with four broadcast ports (BC 1  through BC 4 ) and ten data ports (P 1  through P 10 ). As diagram  1100  illustrates, a bus structure utilized by such a system can be substantially similar to that utilized for the alternate port implementation illustrated in diagram  1000 . 
     Referring now to  FIGS. 12-13 , methodologies that can be performed in accordance with various aspects set forth herein are illustrated. While, for purposes of simplicity of explanation, the 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 can, in accordance with one or more aspects, occur in different orders and/or concurrently with other acts from that shown and described herein. For example, those skilled in the art will understand and appreciate 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 aspects. 
     With reference to  FIG. 12 , illustrated is a methodology  1200  for leveraging a substantially synchronous bus system to facilitate multi-radio coexistence for a set of managed endpoints. It is to be appreciated that methodology  1200  can be performed by, for example, a wireless device (e.g., wireless device  110  or  200 , via a CxM  240 ) and/or any other appropriate network device. Methodology  1200  can begin at block  1202 , wherein respective managed endpoints (e.g., CxM endpoints  430 ) associated with respective potentially conflicting radio technologies and a multi-radio coexistence platform (e.g., CxM  240 ) associated with the respective managed endpoints are identified. Methodology  1200  can then conclude at block  1204 , wherein a bus system is maintained that includes one or more buses operating in a synchronous manner (e.g., synchronous bus(es)  410 ) that communicatively connect the respective managed endpoints to the multi-radio coexistence platform. 
       FIG. 13  illustrates a second methodology  1300  for leveraging a substantially synchronous bus system to facilitate multi-radio coexistence for a set of managed endpoints. Methodology  1300  can be performed by, for example, a multi-radio device (e.g., via a CxM  240 ) and/or any other suitable network entity. Methodology  1300  begins at block  1302 , wherein respective managed endpoints associated with respective potentially conflicting radio technologies and a multi-radio coexistence platform associated with the respective managed endpoints are identified. At block  1304 , at least one bus operating in a synchronous manner is maintained that is configured to collect notifications for the multi-radio coexistence platform from at least one managed endpoint at a first time interval, to await processing of the notifications by the multi-radio coexistence platform at a second time interval subsequent to the first time interval, and to facilitate conveyance of coexistence commands from the multi-radio coexistence platform to the at least one managed endpoint at a third time interval subsequent to the second time interval (e.g., as illustrated by diagram  900 ). 
     Referring now to  FIG. 14 , an apparatus  1400  that facilitates implementation and management of a synchronous bus architecture for multi-radio coexistence management within a communication system is illustrated. It is to be appreciated that apparatus  1400  is represented as including functional blocks, which can be functional blocks that represent functions implemented by a processor, software, or combination thereof (e.g., firmware). Apparatus  1400  can be implemented by a wireless device (e.g., wireless device  110  or  200 , via a CxM  240 ) and/or another suitable network device and can include a module  1402  for identifying respective endpoints corresponding to a set of radio technologies and an application platform that manages coexistence between the set of radio technologies and their corresponding endpoints and a module  1404  for maintaining a system of one or more buses operating in a synchronous manner that facilitate communication between the respective endpoints and the application platform. 
     With respect to the above description, one of ordinary skill in the art can appreciate that various aspects described above can be implemented by hardware, software, firmware, middleware, microcode, or any combination thereof. When the systems and/or methods are implemented in software, firmware, middleware or microcode, program code or code segments, they can be stored in a machine-readable medium, such as a memory or storage device. A code segment can represent a procedure, a function, a subprogram, a program, a routine, a subroutine, a module, a software package, a class, or any combination of instructions, data structures, or program statements. A code segment can be coupled to another code segment or a hardware circuit by passing and/or receiving information, data, arguments, parameters, or memory contents. Information, arguments, parameters, data, etc. can be passed, forwarded, or transmitted using any suitable means including memory sharing, message passing, token passing, network transmission, etc. 
     Moreover, those of skill in the art can appreciate that information and signals can be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and/or chips that may be referenced throughout the above description can be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof. 
     In addition, it is to be understood that the steps of the various methods and/or algorithms as described in connection with the disclosure above can be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An example storage medium can be coupled to a processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium can be integral to the processor. The processor and the storage medium can reside in an ASIC, which in turn can reside in a user terminal and/or in any other suitable location. Alternatively, processor and the storage medium can reside as discrete components in a user terminal. 
     The above description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein, but is instead to be accorded the widest scope consistent with the principles and novel features disclosed herein. Furthermore, to the extent that the term “includes” is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term “comprising” as “comprising” is interpreted when employed as a transitional word in a claim. Furthermore, the term “or” as used in either the detailed description or the claims is meant to be a “non-exclusive or.”