Patent Publication Number: US-11664965-B2

Title: Method and system for distributed communication

Description:
CLAIM OF BENEFIT TO PRIOR APPLICATIONS 
     This Patent Application is a Continuation Application of U.S. Pat. No. 11,283,585, filed on Aug. 28, 2020, which is a continuation application of U.S. Pat. No. 10,771,228, which issued on Sep. 8, 2020, which is a Continuation Application of U.S. patent application Ser. No. 15/943,563, filed on Apr. 2, 2018, which is a Continuation Application of U.S. Pat. No. 9,979,532, issued on May 22, 2018, which is a Continuation Application of U.S. Pat. No. 9,264,125, issued on Feb. 16, 2016, which is a Continuation Application of U.S. Pat. No. 8,660,057, issued on Feb. 25, 2014, which claims the benefit of U.S. Provisional Patent Application 61/377,407, entitled, “Method and System for Distributed Communication System,” filed Aug. 26, 2010. The above-referenced applications are hereby incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     Centralized communication devices typically include baseband, radio modem, and radio front-end. The modem modulates and demodulates the carrier signals to encode and decode the transmitted and received information. The front-end includes a power amplifier to amplify the signal being transmitted, a low noise amplifier to amplify the received signals, a time or frequency duplexer, and an antenna to send and receive signals to/from external devices. In a centralized system, the radio modem and the radio front-end are physically close together. Often as a single integrated circuit chip or several chips fixed on circuit boards that cannot move against each other. 
     Many applications require flexibility in changing the position or orientation of antennas. However, in a centralized communication device, the positions are fixed on an integrated chip or a circuit board and there is no flexibility in changing the position. This limits the optimal positioning and orientation of the antenna, which in turn results in lower sensitivity and lower performance of the system. 
     BRIEF SUMMARY 
     This focus of this invention is an improved architecture where a centralized wireless communication system is divided into smaller components. These components are then distributed and placed at different locations for improved performance. The sub-components can support multiple communication mechanisms and standards and more than one sub-component can be used to improve performance. 
     A decentralized communication device is provided that facilitates optimal positioning and orientation of one or more antennas for communicating with external devices. The decentralized communication device includes one or more master components and one or more slave components. The master and the slave components are physically separate and communicate wirelessly. 
     The slave includes the antennas for communicating with external devices as well as a front-end for sending signals to and receiving signals from the antennas. In some embodiments, the front-end includes a time or frequency duplexer, one or more power amplifiers to amplify signals that are sent to the antennas, and one or more low noise amplifiers for amplifying signals received from the antennas. The slave also includes one or more smaller antennas to wirelessly communicate with the master. The slave acts as a frequency translator between the master and an external wireless device. The slave transmits only the information that the slave receives from the master to the external devices. In some embodiments, the slave communicates with the external device using a first frequency and communicates with the master using a second frequency which is higher than the first frequency. 
     The master includes a digital baseband module and a radio modem. The digital baseband receives bits of digital data and performs digital modulation on the data and sends the digital signal to the radio modem. The radio modem in some embodiments converts the digital signal to analog signal, performs filtering and gain control, and up-converts a carrier frequency. The radio modem sends the encoded signal to a front-end dedicated to one or more small antennas that are used to wirelessly communicate with the small antennas of the slave. 
     The radio modem also down converts received signals from the carrier frequency, performs analog to digital conversion and sends the information to the baseband module for processing. Placing the large antennas required to communicate with the external devices in the slave which is physically separate from the master, allows the slave antennas to be placed in more optimal locations and more optimal orientations to achieve improved sensitivity, performance, and diversity. 
     In some embodiments, one or more masters and one or more slaves are included in an electronic device such as a television (TV), a computer, a laptop, a gaming device, etc. to use the master to communicate wirelessly with external devices by using the slaves as intermediaries. In some of these embodiments, the master performs beam-forming by changing the radio frequency (RF) delays, phases and amplitudes for different slaves in order to maximize the signal received at the external device. 
     Some embodiments implement Multiple Input Multiple Output (MIMO) wireless communication between the master and slave and/or between the slave and the external devices to improve system performance. One advantage of this method is that by separating the front-end from the master, the multiple antennas of the slaves can be placed further apart and hence provide better antenna diversity since the antennas will experience different multipath and fading characteristics. The greater distance between the antennas of the slaves means less interference between the antennas. MIMO wireless systems use diversity coding to improve system performance. With diversity coding the signal is coded using space-time coding methods. These coding methods exploit the independent fading characteristics of the multiple antenna signal paths. MIMO systems also offer spatial multiplexing where a signal is divided into several lower rate streams and each stream is transmitted from a different transmit antenna in the same frequency channel. Spatial multiplexing increases channel capacity at higher signal to noise ratios (SNR). 
     The preceding Summary is intended to serve as a brief introduction to some embodiments of the invention. It is not meant to be an introduction or overview of all inventive subject matter disclosed in this document. The Detailed Description that follows and the Drawings that are referred to in the Detailed Description will further describe the embodiments described in the Summary as well as other embodiments. Accordingly, to understand all the embodiments described by this document, a full review of the Summary, Detailed Description and the Drawings is needed. Moreover, the claimed subject matters are not to be limited by the illustrative details in the Summary, Detailed Description and the Drawing, but rather are to be defined by the appended claims, because the claimed subject matters can be embodied in other specific forms without departing from the spirit of the subject matters. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The novel features of the invention are set forth in the appended claims. However, for purpose of explanation, several embodiments of the invention are set forth in the following figures. 
         FIG.  1    illustrates a centralized communication device that communicates with two external devices according to prior art. 
         FIG.  2    conceptually illustrates an overview of a decentralized communication device in some embodiments of the invention. 
         FIG.  3    illustrates a device with a conventional centralized Radio Frequency (RF) communication device according to prior art. 
         FIG.  4    conceptually illustrates a distributed communication device in some embodiments of the invention. 
         FIG.  5    conceptually illustrates a more detailed diagram of  FIG.  4   . 
         FIG.  6    conceptually illustrates the architecture of a distributed communication device of some embodiments of the invention where the slave has additional functionality compared to  FIG.  5   . 
         FIG.  7    conceptually illustrates the architecture of a distributed wireless communication device of some embodiments of the invention where only the master has beam steering capability with multiple small HF antennas. 
         FIG.  8    conceptually illustrates the architecture of a distributed wireless communication device in some embodiments of the invention where only the slave has multiple small HF antennas for internal communication between the slave and the master. 
         FIG.  9    conceptually illustrates the architecture of the distributed wireless communication device of some embodiments of the invention with multiple master and slave small HF antennas for internal communication between the master and the slave. 
         FIG.  10    conceptually illustrates the architecture of a distributed wireless communication device of some embodiments of the invention with the slaves having multiple external communication antennas for communication and beam forming between the slave and the external device. 
         FIG.  11    conceptually illustrates the architecture of the distributed wireless communication device of some embodiments of the invention with the slave having multiple external communication antennas together with a MIMO implementation. 
         FIGS.  12 ( a )- 12 ( d )  conceptually illustrate four different methods in some embodiments of the invention for placing an electronic device&#39;s radio antenna at a distant location from the device such that the device can communicate with external devices. 
         FIG.  13    conceptually illustrates an electronic device of some embodiments of the invention that uses the system shown in  FIG.  12 ( d )  for wireless communication with external devices. 
         FIG.  14    conceptually illustrates a distributed communication device using beam-forming in some embodiments of the invention, where there is one effective communication channel with the external device. 
         FIG.  15    conceptually illustrates a MIMO implementation of some embodiments of the invention. 
         FIG.  16    conceptually illustrates a process for the master dynamically changing the system configuration to optimize system performance in some embodiments of the invention. 
         FIG.  17    conceptually illustrates an implementation for a gaming application in some embodiments of the invention. 
         FIG.  18    conceptually illustrates an electronic system with which some embodiments of the invention are implemented. 
         FIG.  19    conceptually illustrates a distributed communication device of some embodiments of the invention where a master uses more than one slave to communicate with an external device. 
         FIG.  20    conceptually illustrates two masters directly communicating with each other without using a slave as an intermediary in some embodiments of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description of the invention, numerous details, examples, and embodiments of the invention are set forth and described. However, it will be clear and apparent to one skilled in the art that the invention is not limited to the embodiments set forth and that the invention may be practiced without some of the specific details and examples discussed. 
     A decentralized communication device is provided that facilitates optimal positioning and orientation of one or more antennas for communicating with external devices. The decentralized communication device includes one or more master components and one or more slave components. The master and the slave components are physically separate and communicate wirelessly. 
     The slave includes the antennas for communicating with external devices as well as a front-end for sending signals to and receiving signals from the antennas. In some embodiments, the front-end includes a time or frequency duplexer, one or more power amplifiers to amplify signals that are sent to the antennas, and one or more low noise amplifiers for amplifying signals received from the antennas. The slave also includes one or more smaller antennas to wirelessly communicate with the master. The slave acts as a frequency translator between the master and an external wireless device. The slave transmits only the information that the slave receives from the master to the external devices. In some embodiments, the slave communicates with the external device using a first frequency and communicates with the master using a second frequency which is higher than the first frequency. 
     The master includes a digital baseband module and a radio modem. The digital baseband receives bits of digital data and performs digital modulation on the data and sends the digital signal to the radio modem. The radio modem in some embodiments converts the digital signal to analog signal, performs filtering and gain control, and up-converts a carrier frequency. The radio modem sends the encoded signal to a front-end dedicated to one or more small antennas that are used to wirelessly communicate with the small antennas of the slave. 
     The radio modem also down converts received signals from the carrier frequency, performs analog to digital conversion and sends the information to the baseband module for processing. Placing the large antennas required to communicate with the external devices in the slave which is physically separate from the master, allows the slave antennas to be placed in more optimal locations and more optimal orientations to achieve improved sensitivity, performance, and diversity. 
     The master and the slave have independent power sources in some embodiments. The slave in some embodiments operates with wireless power (RF or induction), or has small batteries that are rechargeable. 
     In some embodiments, one or more masters and one or more slaves are included in an electronic device such as a television (TV), a computer, a laptop, a gaming device, etc. to use the master to communicate wirelessly with external devices by using the slaves as intermediaries. In some of these embodiments, the master performs beam-forming by changing the radio frequency (RF) delays, phases and amplitudes for different slaves in order to maximize the signal received at the external device. 
     In some embodiments, an electronic device (e.g. TV, laptop) uses distributed slaves, where the slaves use different frequencies and standards for communicating with external wireless devices, thereby becoming a wireless router and supporting different wireless standards such as Wireless Local Area Network (WLAN) 802.11*, 802.11ac, 802.11ad, cellular (second generation (2G), third generation (3G), fourth generation (4G), etc.), Bluetooth®, Worldwide Interoperability for Microwave Access (WiMAX), 60 GHz, HD Radio™ and Ultra-wideband standards. 
     The external device in some embodiments is a gaming remote and a group of slaves are used to track the remote and give tracking information to the master which gives it to the gaming controller. The remote in some embodiments is small enough that it is wearable on human fingers. The remote in some of these embodiments also operates with wireless power or has small batteries that are rechargeable. 
     Some embodiments implement Multiple Input Multiple Output (MIMO) wireless communication between the master and slave and/or between the slave and the external devices to improve system performance. One advantage of this method is that by separating the front-end from the master, the multiple antennas of the slaves can be placed further apart and hence provide better antenna diversity since the antennas will experience different multipath and fading characteristics. The greater distance between the antennas of the slaves means less interference between the antennas. MIMO wireless systems use diversity coding to improve system performance. With diversity coding the signal is coded using space-time coding methods. These coding methods exploit the independent fading characteristics of the multiple antenna signal paths. MIMO systems also offer spatial multiplexing where a signal is divided into several lower rate streams and each stream is transmitted from a different transmit antenna in the same frequency channel. Spatial multiplexing increases channel capacity at higher signal to noise ratios (SNR). 
     Some embodiments support multiple wireless communication standards (e.g. WLAN, 802.11*, 802.11ac, 802.11ad, cellular second generation (2G), cellular third generation (3G), cellular fourth generation (4G), Bluetooth®, Worldwide Interoperability for Microwave Access (WiMAX), 60 GHz, HD Radio™ and Ultra-wideband standards). The master and slave and/or the slave and the external devices in some embodiments communicate with more than one radio type (e.g. Bluetooth® and WLAN) at the same time, or they communicate with more than one radio type at different times. In some embodiments, the slave includes a signal processing component for demodulating, re-modulating and reformatting for other standards. 
     Some embodiments include more than one master and/or more than one slave for improved performance. In some of these embodiments the processing of the information is distributed between the slaves, the master (or masters if there are more than one) and other devices such as a gaming controller or a network server or cloud computing server. A master in some embodiments chooses a number of slaves from a group of slaves and uses them to communicate with an external device. The master in some embodiments uses beam-forming when communicating internally with each slave. In some embodiments the master uses beam-forming between a group of slaves that communicate with an external device. In some embodiments, the master uses space-time coding and individual multi-antenna slaves do beam-forming for communicating with an external device. The master uses space-time-frequency coding in some embodiments where the slaves use different frequencies to communicate with the external device. 
     The master in some embodiments chooses which group of slaves out of a matrix of slaves to communicate with based on a selection criteria such as optimal Bit Error Rate (BER), SNR, power consumption, or Electronic Vector Magnitude (EVM). This can be done dynamically, where if an obstacle is introduced between one of the slaves and the external device, then the master dynamically switches to another slave, or if the battery level is low the master chooses a fewer slaves (e.g., two slaves instead of four) for diversity coding. 
     Some embodiments provide a decentralized communication device is provided that facilitates optimal positioning and orientation of one or more antennas for wireless communication with external devices. The decentralized communication device includes one or more master components and one or more slave components. The master and the slave components are physically separate and communicate wirelessly. In some embodiments the slave acts as a carrier frequency translator between the master and an external wireless device, where it communicates with the external device using a first frequency and communicates with the master using a second frequency which is different from the first frequency. 
     In other embodiments the slave has most or all the physical layer to do the digital coding, digital modulation, data framing, data formatting and data packetization for communicating with an external device, in which case digital coding and digital modulation is distributed between the master and the slave. In yet other embodiments the master uses slave-to-slave communication to exchange information with an external device. In some embodiments, one or more masters and one or more slaves are included in an electronic device to use a master to communicate wirelessly with external devices by using a subset of the slaves as intermediaries. Some embodiments implement MIMO wireless communication and/or beam-forming to improve system performance. In some embodiments the slaves and/or the masters operate with wireless power. In other embodiments two masters may communicate directly with each other without using any slaves. Several more detailed embodiments of the invention are described in sections below. 
     I. Decentralizing Components of a Communication System 
     A. Overview 
       FIG.  1    illustrates a centralized communication device that communicates with two external devices according to prior art. The communication between the centralized communication device  100  and the external devices  105  and  110  could be done by wireless or wired methods such as radio-frequency, microwave, laser, optical, ultrasound, induction, or other electromagnetic methods. 
       FIG.  2    conceptually illustrates an overview of a decentralized communication device  200  in some embodiments of the invention. In contrast with the centralized communication device of  FIG.  1   , the decentralized centralized communication device  200  is divided into distributed sub-components. The sub-components include at least one master component  205  (also referred to as master sub-component, master unit, or master device) and one slave component  210  (also referred to as slave sub-component, slave unit, or slave device). Some embodiments include more than one master and/or more than one slave. Also, the master and the slave each includes several components, modules, blocks, or units which are described further below. 
     In some embodiments, a master component uses one or more slave components to communicate with external devices. For instance, in  FIG.  2    the master  205  uses slave components  1 ,  2  and  3  to communicate with external device A  215 . The figure also shows the master  205  using slave component  4  to communicate with external device B  220 . The master  205  and each slave sub-component  210  can communicate with different mechanisms such as a wire, or wireless methods such as radio-frequency, microwave, laser, optical, induction, or other electromagnetic methods. For example, one slave can use a wire while another slave uses optics and another slave uses RF, etc. The slave and external devices can also use one or more of these methods to communicate with each other. 
       FIG.  3    illustrates a device  300  with a conventional centralized Radio Frequency (RF) communication system according to prior art. One conceptual partitioning of the system is the digital baseband  305  and the complete radio  310 , as shown in  FIG.  3   . The complete radio  310  can be further conceptually partitioned into the modem  315  and the front-end  320 , as shown in  FIG.  3   . The modem  315  performs digital to analog conversion and up-converts to a carrier frequency for transmission by antenna. In some systems the up-conversion is a two-step process where Tx  365  up-convert from 0 to an intermediate frequency and mixer  370  up-convert to carrier frequency f 1 . The modem also down-converts from carrier frequency the signals received from the antenna and performs analog to digital conversion. The front-end includes the Power Amplifier (PA)  325 , Low Noise Amplifier (LNA)  330 , duplexer  335 , and antenna  340 . In a centralized system the radio modem and the radio front-end are physically close together, often as a single integrated circuit chip or on circuit boards physically connected together. The positions are fixed on an integrated chip or circuit board so there is no flexibility in changing the position. This limits the optimal positioning and orientation of the antenna, which in turn results in lower sensitivity and performance of the system. 
     In  FIG.  3   , the radio system  300  has a power source  345  for all its components. During transmission the system&#39;s digital baseband  305  receives bits of data from memory  350 , a Digital Signal Processor (DSP)  355 , and/or a processor  360 . The digital baseband then performs digital coding to reduce redundancy and generate symbols. It also performs digital modulation. Additional functions performed by the baseband are data formatting and framing for a particular standard (e.g. 802.11) and data packetization. The baseband modulated signals are then fed to a transmitter (Tx)  365 . Transmitter  365  may also perform some coding and digital modulation prior to using its Digital to Analog Converter (DAC) for analog conversion of the signal. Thus, coding and digital modulation is performed by baseband  305  and transmitter  365 . Partitioning of these digital operations can vary from one system to another. Some examples of coding are convolutional coding and Vitterbi coding. Some examples of digital modulation techniques are Quadrature Phase-Shift Keying (QPSK), Frequency-Shift Keying (FSK), Amplitude-Shift Keying (ASK), and Quadrature Amplitude Modulation (QAM). 
     The transmitter  365  also performs filtering and gain control, before feeding the signal into an up-converter mixer  370 . A clock  375  and a Phase Lock Loop (PLL) synthesizer  380  are used to generate an RF transmit carrier frequency, which is mixed with the transmitter&#39;s signal to generate a modulated RF carrier signal of frequency f 1 . This signal is then amplified by a Power Amplifier (PA)  325  and fed to a frequency or time duplexer  335 . The duplexer  335  connects the PA&#39;s output signal to an antenna  340  during transmission so that the antenna  340  radiates the modulated RF signal over the airwaves to a receiver (e.g. the an external device  385 ) or set of receivers. In transmission path, the baseband frequency (e.g., frequency of 0) is either up-converted by the mixers to a carrier frequency (e.g., 60 GHz) or the baseband frequency is converted by the transmitter to an intermediate frequency and then the intermediate frequency is up-converted by the mixers to the carrier frequency. In receiver path, the reserve conversions are performed. 
     During reception the radio system&#39;s antenna  340  receives an RF modulated carrier signal of frequency f 1  and the duplexer  335  connects the antenna  340  to a Low Noise Amplifier (LNA)  330 . The LNA  330  amplifies this signal and feeds it to a down-converter mixer  390 . A clock  395  and a Phase Lock Loop (PLL) synthesizer  397  are used to generate an RF signal of the same f 1  frequency as the transmit carrier frequency. The down-converter mixer  390  down-converts the signal by mixing it with this RF generated signal. In some systems the down-conversion is a two-step process where mixer  390  down-convert to an intermediate frequency and Rx  399  down-converts to 0. 
     The down-converted signal is then fed to a receiver (Rx)  399  which includes an Analog to Digital Convertor (ADC). The receiver  399  performs analog gain control and filtering before feeding the signal to its ADC for digital conversion. Receiver  399  may then also perform some digital demodulation and decoding after the digital conversion of the signal. The digital baseband  305  then processes the digital signal with decoding and demodulation operations to extract the data bits. Thus, digital demodulation is performed by receiver  399  and baseband  305 . The baseband then provides the extracted data to the processor  355 , DSP  360 , and/or memory  350 . The size of the antenna  340  depends on the frequency f 1 ; the lower the frequency the larger the antenna. 
     B. Master and Slave Components with Single Internal Antenna 
     The examples illustrated throughout this specification use a Radio Frequency (RF) wireless communication system to demonstrate the invention. However, the architecture is general and applies to other wireless communication systems.  FIG.  4    conceptually illustrates a distributed communication device in some embodiments of the invention. The radio modem  405  and the front-end (labeled “Slave”)  410  are distributed at separate locations and transfer data wirelessly to each other. In this embodiment, the modem  405  is part of another component of the device (labeled Master)  415  and transfers data to/from this component&#39;s memory  420 , DSP  425 , and/or a processing unit (such as a processor)  430 . 
     The slave is not an independent system and acts as a slave to the master. For instance, the slave does not transmit information generated by the slave to an external device  450 . The master doesn&#39;t always generate information that it transmits to the slave (e.g., it may receive it from an outside memory or DSP). In one application a person talks into a device. The device digitizes the voice and sends the digitized voice data to the master. The master then performs digital coding, modulation, and packetization before transmitting the data to the slave, and the slave re-transmits the data to an external device. In another application the master receives information wirelessly from a slave or set of slaves that originated from an external device, and retransmit the information (through wire) to an electronic device (e.g., to a TV&#39;s processor or a game controller). The slave re-transmits information it receives from the master. In some embodiments the master instructs a first slave to communicate with a second slave, and the second slave communicates with an external device. This could be extended where the second slave communicates with a third slave and the third slave communicates with an external device. In another embodiment a master communicates directly with another master without using any slaves in between. 
     The slave  410  is comprised primarily of a PA, LNA, duplexer and antenna, but in some embodiments also includes other components (or modules). In some embodiments the slave  410  also has its own radio modem. For example, the slave  410  in some embodiments includes most or all the physical layer to do coding and digital modulation. The wireless communication between the master  405  and the front-end  410  is RF, microwave, laser, induction, optical or other electromagnetic frequencies and methods in different embodiments. In some embodiments, however, the communication is a wire-line mechanism such as a Universal Serial Bus (USB), PCI express, cable or transmission line. The two parts  405  and  410  also use a control channel  435  for synchronization of clocks, gain control, programming, calibration and changing of parameters. 
     In some embodiments the master, the slave, and the external device are physically separated and are not on the same chip, circuit board, or physical device. In some embodiments some or all of the master, the slave, and the external device are on the same device but the external device&#39;s wireless communication components are on a separate circuit board from the master and the slave. In other embodiments the master, the slave and the external device are integrated circuits that are on a single board or on multiple boards of the same physical device and are used for chip-to-chip communication. 
     In some embodiments, master, slave, or both include one or more processing units and a machine readable or computer readable medium that includes a program to implement the methods (such as selecting different frequencies, selecting which external device(s), which slave(s), or which master(s) to communicate with, selecting different antennas to communicate, selecting a communication path that reduces interference and multipath, using a control channel to program or calibrate the slave, etc.) required for implementing the techniques discussed by reference to  FIGS.  2  and  4 - 16    for implementing a distributed communication device. 
       FIG.  5    conceptually illustrates a more detailed diagram of  FIG.  4   . In contrast to the device  300  of the centralized communication system of  FIG.  3   , the decentralized device of  FIG.  5    is split into two components  505  and  510  that are physically separate, located at different positions, and communicate wirelessly. Component  505  can be viewed as a back-end master module that includes the modem  515 . The second Component  510  can be viewed as a slave or external communication front-end module. The master  505  uses the slave  510  to communicate wirelessly with other devices such as the external device  520 . The baseband  525  and modem  515  of a conventional centralized radio are in the master  505 . In some embodiments, baseband  525  has its own memory, DSP, and processing unit (e.g., processor). In other embodiments, the baseband uses the master&#39;s memory, DSP, and processing unit ( 420 ,  425 ,  430 ). The baseband  525  and modem  515  perform digital coding and modulation. However, instead of using a large external antenna operating at a relatively lower carrier frequency, f 1 , the device  505  uses a small antenna  530  that operates at a higher carrier frequency, f 2 , to communicate internally with the slave. For example, consider the case where f 2  is 60 GHz and f 1  is 2.4 GHz. The size of the antenna is proportional to the wavelength or inversely proportional to the frequency. The size of a 60 GHz antenna (typically a few millimeters) is therefore about 25 times smaller than a 2.4 GHz antenna (typically a few centimeters). A 60 GHz antenna can therefore fit on a chip or package. It should be stated that small antenna  530 ,  535  and larger antenna  540  operate in a frequency band so f 2  and f 1  can vary slightly in the band range for each antenna and device. The slave performs an interconnection function, as opposed to a relaying or range extending function. With a relay device the frequencies f 1  and f 2  are close to each other and are in the same frequency band such as the 2.4 GHz band. In this specification the slave&#39;s f 1  and f 2  frequencies can be orders of magnitude different (e.g. 2.4 GHz and 60 GHz). Different components or modules of the master and the slave are described in the following paragraphs. 
     Master  505  includes the front-end for driving the internal antenna  530 . The slave uses its small high frequency antenna  535  to communicate internally with the master  505  using carrier frequency f 2 . However, the slave  510  also has a larger external antenna  540  that operates at the lower f 1  carrier frequency for communicating over larger distances with outside devices. The mixers  545  and  550  of the slave essentially convert between these two carrier frequencies, f 1  and f 2 , thereby allowing the master  505  to use the slave  510  to communicate with distant devices (such as the external device  520 ) with carrier frequency f 1 . Thus, master  505  performs all the digital coding/decoding and modulation/demodulation and slave  510  acts like a frequency converter by translating the carrier frequency at its two ends. Thus, master  505  and the slave  510  communicate internally with the smaller antennas and higher carrier frequency f 2  over short distances, while the slave  510  and external device(s)  520  communicate with the larger external antenna and lower carrier frequency f 1  over larger distances. 
     Every module in slave  510  and master  505  is programmable and can be calibrated. Examples are the tuning frequency of the PA and LNA, gain control, clock timing and synchronization, PLL parameters, capacitors, inductors, transistors, digital bits, programming, etc. The master  505  and the slave  510  each have control units  545  and  550 , respectively that communicate over a control channel  555 . The master in some embodiments uses control channel  555  to program and calibrate the above parameters for the slave. The slave in  FIG.  5    is a simple slave that changes the carrier frequency of the master&#39;s transmission. However, other slaves are more powerful and perform additional functions such as digital coding/decoding, modulation/demodulation, and data framing and reformatting (e.g., as shown below in  FIG.  6   , block  615  of slave  610 ) that set the communication mode with the external device (e.g. 802.11/Bluetooth®/CDMA) or change it from one standard to another (e.g. from 60 GHz standard to 802.11/Bluetooth®/CDMA standards). Thus, for a more powerful slave such as  610  the control channel is also used in some embodiments to change its mode of behavior for different standards. For example, the master can use control channel  555  to configure the slave&#39;s mode of communication with external device  520  to be Wi-Fi (802.11) or CDMA. The control channel  555  is a wire, power supply modulation, induction/magnetic coupling, or another wireless channel in different embodiments that can be a lower or higher frequency compared to the internal communication frequency which is shown as f 2  in  FIG.  5   . 
     The master  505  and the slave  510  both have their power sources  560  and  565 , respectively, for their components. These power sources  560  and  565  are AC power, inductive power, or RF power in different embodiments. The slave in some embodiments operates with wireless power (RF or induction), and/or has small batteries that are rechargeable. The master  505  and the slave  510  get their clocks from the power signal in the embodiments that either the master or the slave does not have clocks. For example, the power supply of the master or the slave in some embodiments has a modulation such as an AC superimposed on a DC and the radio selectively filters or blocks the DC and chooses the frequency for the clock. 
     In some embodiments, the high carrier frequency f 2  corresponds to a standard&#39;s carrier frequency such as 60 GHz or 100 GHz, but in other embodiments the high frequency f 2  is any high frequency and the slave is just a frequency translator. For example, on transmission the master performs digital coding and digital modulation for WLAN 802.11 (where that standard uses 2.4 GHz as the carrier frequency) but the master up-converts to carrier frequency f 2  where f 2  is different from 2.4 GHz. The slave then changes the carrier frequency to f 1  where f 1  is 2.4 GHz and re-transmits to the external device. This changing of the carrier frequency does not affect the digital coding and modulation that was performed by the master; it just changes the airwave carrier frequency. When the external device is transmitting to the slave, the external device performs 802.11 digital coding and modulation and transmits with f 1 =2.4 GHz carrier frequency to the slave. The slave changes the carrier frequency to f 2  and re-transmits to the master. The master then down-converts the carrier frequency, performs digital demodulation and decoding, and forwards the extracted data to its processor. This method also applies to high frequency transmission standards such as 60 GHz or 100 GHz (e.g. f 1 =60 GHz and f 2 =65 GHz, so both internal and external communication carrier frequencies are high). 
     In other embodiments (as shown in  FIG.  6   , below) the slave has a radio modem with signal processing components and memory for digital coding/decoding, modulating/demodulating, and formatting/reformatting for other standards. For example, in  FIG.  6    on transmission the master performs some digital modulation and up-converts to carrier frequency f 2 . The slave receives the master&#39;s transmission, down-converts, performs demodulation, performs digital coding, performs digital modulation for the WLAN 802.11 standard, up-converts to carrier frequency 2.4 GHz, and transmits to external device). 
     In yet other embodiments the masters and the slaves have combined radios to support multiple wireless standards such as WLAN 802.11*, 802.11ac (&lt;6 GHz), 802.11ad (60 GHz), cellular second generation (2G), cellular third generation (3G), cellular fourth generation (4G), Bluetooth®, Worldwide Interoperability for Microwave Access (WiMAX), 60 GHz, HD Radio™ and Ultra-wideband standards. 
     The master  505  illustrated in  FIG.  5    uses a Radio Frequency (RF) system. The master has a power source  560  for all its components. During transmission the master  505  digital baseband  525  receives bits of data from memory, a Digital Signal Processor, DSP, and/or a processing unit (as shown in  FIG.  4   ). In some embodiments, memory, Digital Signal Processor (DSP), and processor are part of the master. In other embodiments, the master receives the data from another device. The digital baseband generates symbols and performs digital modulation. 
     The baseband modulated signals are fed to a transmitter (Tx)  570  which in some embodiments performs additional digital modulation. Transmitter  570  includes a Digital to Analog Converter (DAC) for analog conversion of the signal. The transmitter  570  also performs filtering and gain control, before feeding the signal into an up-converter mixer  575 . A clock  577  and a Phase Lock Loop (PLL) synthesizer  579  are used to generate an RF transmit carrier, which is mixed with the transmitter&#39;s signal to generate a modulated RF carrier signal of frequency f 1 . A second clock  580  and Phase Lock Loop (PLL) synthesizer  582  are used to generate an RF transmit carrier, which is mixed with the transmitter&#39;s signal by a second up-converter mixer  584  to generate a modulated RF carrier signal of frequency f 2 . In other embodiments, the two sets of up-converter mixers  575  and  584  and their associated clock and PLL are combined into one set where one mixer generates a modulated RF carrier signal of frequency f 2  without going through the intermediate step of generating f 1 . 
     The f 2  modulated signal is then amplified by a Power Amplifier (PA)  585  and fed to a frequency or time duplexer  587 . This amplifier  585  (and the corresponding amplifier  527  in the slave  510  that drives the small high frequency (HF) antenna  535  for internal communication) does not have to be high power compared to amplifier  595  because amplifier  585  has to cover the smaller distance between the master and the slave (compared to the longer distance between the slave and the external device  520 ). For example, the power of amplifier  585  (and  527 ) is typically of the order of milli-Watts while the power of amplifier  595  is 100-1000 times more and is of the order of Watts. Both amplifiers, however, have power control and change their gains accordingly. The duplexer  587  connects the PA&#39;s output signal to the small high frequency antenna  530  during transmission so that the antenna  530  radiates the modulated RF signal over the airwaves to a receiver (e.g. the slave  510  in the figure) or a set of receivers. 
     The small high frequency antenna  535  of the slave  510  receives the RF modulated carrier signal of frequency f 2  and the duplexer  589  connects the antenna  535  to a Low Noise Amplifier (LNA)  590 . The LNA  590  amplifies this signal and feeds it to a down-converter mixer  550 . A clock  592  and a Phase Lock Loop (PLL) synthesizer  594  are used to generate an RF signal of frequency f 1  which is the transmit carrier of the target external device  520  or devices. The down-converter mixer  550  down-converts the signal to frequency f 1  by mixing it with this RF generated signal, and the resulting signal is then amplified by a Power Amplifier (PA)  595  and fed to a frequency or time duplexer  596 . The duplexer  596  connects the PA&#39;s output signal to the larger antenna  540  during transmission so that the antenna  540  radiates the f 1  modulated RF signal over the airwaves to a receiver (e.g. the external device  520 ) or a set of receivers. In the embodiments that the duplexers in  FIG.  5    are time duplexers they need the control channel  555  to set the switch to receive or transmit.  FIG.  5    shows the same f 2  frequency for transmission from the master to the slave and transmission from the slave to the master. However, some embodiments use different frequencies for the two directions. If the transmit and receive frequencies are different then the duplexer does not have to be time-multiplexed and can instead use filters to filter out the frequencies. 
     The external device  520  uses the slave  510  to transmit to the master  505 . The large antenna  540  of the slave  510  receives the RF modulated carrier signal of frequency f 1  that originates from the antenna  598  of the external device  520 . The slave&#39;s duplexer  596  connects the large antenna  540  to a Low Noise Amplifier (LNA)  542 . The LNA  542  amplifies this signal and feeds it to an f 2  up-converter mixer  545 . A clock  547  and a Phase Lock Loop (PLL) synthesizer  549  are used to generate an RF signal of the same f 2  frequency as the transmit carrier. 
     The up-converter mixer  545  up-converts the signal by mixing it with this RF generated signal. The up-converted signal is amplified by a Power Amplifier (PA)  527  and fed to a frequency or time duplexer  589 . The duplexer  589  connects the PA&#39;s output signal to the small high frequency antenna  535  during transmission so that the antenna radiates the modulated RF signal over the airwaves to a receiver (e.g. the master  505 ) or a set of receivers. The small high frequency antenna  530  of the master device  505  receives the RF modulated carrier signal of frequency f 2  and its duplexer  587  connects the antenna  530  to a Low Noise Amplifier (LNA)  517 . The LNA amplifies this signal and feeds it to a down-converter mixer  522 . A clock  524  and a Phase Lock Loop (PLL)  526  synthesizer are used to generate an RF signal of frequency f 2 . The down-converter mixer  522  down-converts the signal to frequency f 1  by mixing it with this RF generated signal. Another clock  528  and another Phase Lock Loop (PLL) synthesizer  529  are used to generate an RF signal of frequency f 1 , which is mixed by the down-converter mixer  534  with the down-converted signal to down-convert the signal further for the receiver (Rx)  551 . 
     In other embodiments the two sets of down-converter mixers  522  and  534  and their associated clock and PLL can be combined into one set without going through the intermediate step of generating an f 1  down-converted signal. Also,  FIG.  5    shows two clocks in the slave and four clocks in the master for frequency conversion. However, the same clock can be used for the opposite directions of transmit and receive if the frequencies are the same, so the slave in some embodiments has just one clock and the master has two clocks (in some embodiments that frequency conversion in the master bypasses the intermediate f 1  and goes directly to f 2 , the master has just one clock). The receiver  551  performs analog gain control, filtering and feeds the signal to its Analog to Digital Convertor (ADC) for digital conversion. Receiver  551  in some embodiments also performs some digital demodulation before sending the signal to the digital baseband. The digital baseband  525  then processes the digital signal to extract the data bits and provide them to other components that are not shown such as a processing unit, DSP, and/or memory. 
       FIG.  6    conceptually illustrates the architecture of a distributed communication device of some embodiments of the invention where the slave  610  has additional functionality compared to  FIG.  5   . In particular, the slave has most or all the physical layers to do digital modulation, demodulation and coding. This is performed in the slave radio modem  615 . In  FIG.  6    the slave&#39;s radio modem includes a simpler DSP and/or processor and memory. The slave&#39;s radio modem  615  is between two sets of mixers  620  and  625  which change the carrier frequency before and after the slave&#39;s modem  615 . However, changing the carrier frequency has no effect on the digital modulation and coding; it merely changes the carrier frequency over the airwaves. 
     Unlike,  FIG.  5    where all the digital modulation and coding was performed in the master, in  FIG.  6    digital modulation and coding is distributed between the master and the slave. For example, when the master is transmitting, the master&#39;s digital baseband  630  and transmitter Tx  635  may perform some digital modulation and coding, but the slave&#39;s radio modem performs the bulk of digital modulation and coding. Consider the case where the master is using the slave to transmit to an external device that has an 802.11 transceiver. The master may perform a limited amount of digital coding and modulation, but the slave&#39;s modem performs most of the digital coding, digital modulation, data framing, data formatting and data packetization for the 802.11 standard. The slave&#39;s modem in some embodiments also performs digital demodulation, coding, and modulation between two standards (e.g. 60 HGz standard and WLAN 802.11 standard operating with carrier frequency 2.4 GHz, 3.6 GHz or 5 GHz). Thus, if the master has performed digital coding and modulation for a different standard than the one that the external device supports or requests then the slave can demodulate and decode the data it receives from the master, and perform the correct digital coding and digital modulation for the slave&#39;s standard. 
     Slave  610  is also capable of communicating with another slave if instructed with the master&#39;s control channel to do so because slave  610  has memory and processing power in  615 . In this embodiment the slaves&#39; antennas and modems are bi-directional and can use time duplexing to transmit and receive over the same HF antenna if necessary.  FIG.  19    conceptually illustrates a distributed communication device of some embodiments where a master uses more than one slave to communicate with an external device. The figure shows a master  1905  that has performed digital modulation, coding and data formatting for a Wi-Fi (802.11) transmission to an external device  1975  and wants to use a first slave as an intermediary in between the two. However, first slave  1910  is not addressable by master  1905  because it is too distant or because there is an obstacle in between the two. Master  1905  then uses its control channel  1950  to address and activate a second slave  1912  which is near the first slave  1910  and can communicate with it. 
     The master uses the higher carrier frequency f 2  and its HF antenna  1955  and transmits the data to the second slave&#39;s HF antenna  1960 . The second slave&#39;s HF antenna  1960  receives the control signals and the data from the master  1905  and sends them to the second slave&#39;s radio modem (e.g., radio modem  615  shown in  FIG.  6   ). The second slave&#39;s radio modem  615  then uses time duplexing and its HF antenna  1960  to re-transmit the data to the first slave&#39;s HF antenna  1980 . The first slave  1910  then receives the information from the second slave  1912  and uses frequency shifting to the lower f 1  frequency and its larger antenna  1970  to make a Wi-Fi (802.11) transmission to the external device  1975 . Although  FIG.  19    shows two slave used as intermediary between the master  1905  and the external device  1975 , master  1905  in some embodiments uses more than two slaves as intermediary where the extra intermediary slaves communicates with each other in a chain. Such a chain can in some embodiments resemble an ad-hoc or mesh network. 
     In other embodiments, the first and or the second slave perform in a distributed fashion some or all of the digital coding, modulation and data framing and formatting for the external device transmission standard (e.g. CDMA, or in this example 802.11). Thus, the slave functionality in  FIG.  6    is more than the carrier frequency converter of  FIG.  5   . 
     C. Distributed Communication Device with Components that Include Multiple Antennas 
     In the embodiments described by reference to  FIGS.  4 - 6   , a single antenna in the master internally communicates with a single antenna on the slave and a single external antenna on the slave communicates with a single antenna on an external device. Multiple antenna systems however improve communication performance with beam-forming, spatial multiplexing, and diversity coding. 
     With single layer beam-forming, the same signal is transmitted from the transmitter&#39;s antennas with different phase and gain settings so that the signals sum constructively at the receiver. This maximizes the received power at the receiver and improves the gain. Beam-forming works well for small delays. If the receiver has multiple antennas, and there is knowledge of the channel state information at the transmitter, then pre-coding with multiple streams is used. 
     With spatial multiplexing, a signal is divided into several lower rate streams and each stream is transmitted from a different transmit antenna in the same frequency channel. This increases channel capacity at higher signal to noise ratios (SNR). The maximum number of stream is limited by the number of antennas at the transmitter and the receiver. 
     Diversity coding is a technique that is used in Multiple Input Multiple Output (MIMO) wireless systems when there is no knowledge of the channel at the transmitter. With diversity coding a single stream is transmitted but the signal is coded using methods such as space-time coding and is transmitted from each antenna with full or near orthogonal coding. Diversity coding takes advantage of the independent fading characteristics of the multiple antenna signal paths and provides better diversity for larger separation distances between the antennas. Spatial multiplexing can also be combined with pre-coding when the transmitter&#39;s channel is known or combined with diversity coding. These techniques are applicable to different embodiments of the invention for communication between the master and the slave and communication between the slave and external devices. 
     i. Components with Multiple Internal Antennas 
       FIGS.  7 - 9    show different multi-antenna configurations for the internal communication between the master and the slave. Different components or modules of the master and the slave in these figures are described in the following paragraphs.  FIG.  7    conceptually illustrates the architecture of a distributed wireless communication device of some embodiments of the invention where only the master has beam steering (or beam-forming) capability with multiple small HF antennas. Three small HF antennas are shown in this example but the number in different embodiments is 2 or more. In  FIG.  7    each antenna  735  is shown as having its own PA  720  and LNA  725 . The master  705  has a beam-forming unit  715  that is placed before the PA  720  and duplexer  730  on the transmit side or after the duplexer  730  and LNA  725  on the receive side. In other implementations, however, the beam-forming unit  715  is placed on the other side of the duplexer. 
     The beam-former  715  generates different phase and amplitudes for each of the antennas  735  in order to steer the beam. Likewise, on the receive side the beam-former  715  takes multiple receive signals from each antenna  735  and combines them with multiple phases/amplitudes. The output of the beam-former  715  results in one communication channel, and hence the antennas share one radio modem  740  (the components of which are shown in  FIG.  5   ). 
     In yet other embodiments, there is no explicit beam-forming component in the master, and the beam-forming function is integrated into the radio modem&#39;s transmitter (Tx) and radio modem&#39;s receiver (Rx) where they generate the phase, and amplitudes for beam-forming (TX and RX components are shown in  FIGS.  5  and  6   ). The transmitter&#39;s beam-former, if it has one, steers and focuses the energy of the transmitted beam on the antenna(s) of the receiver (e.g. in  FIG.  7    beam-former  715  focuses the energy of beam from antennas  735  on the small HF antenna of the slave) for optimum power transfer, while the receiver&#39;s beam-former, if it has one, uses phase shifting information to sum the power from each antenna coherently (e.g. in  FIG.  8    beam-former  815  uses phase shifting to sum the power from small HF antennas  820  coherently). Since noise is uncorrelated this increases the gain and Signal to Noise Ratio (SNR). 
       FIG.  8    conceptually illustrates the architecture of a distributed wireless communication device in some embodiments of the invention where only the slave has multiple small HF antennas for internal communication between the slave and the master. As shown, the slave  810  has beam steering capability with a beam-forming unit  815  and multiple small HF antennas  820  that have their own PAs  825  and LNAs  830 .  FIG.  9    conceptually illustrates the architecture of the distributed wireless communication device of some embodiments of the invention with multiple master and slave small HF antennas for internal communication between the master and the slave. As shown, both the master  905  and the slave  910  have multiple antennas with beam steering capabilities. The discussions about other embodiments for  FIG.  7    also apply to  FIGS.  8  and  9   . As with  FIG.  7   , in  FIGS.  8  and  9    the beam-former results in one communication channel. 
     ii. Slave Components with Multiple External Antennas 
     Multiple antennas may also be used for external communication between the slave and external devices such as the external device labeled in  FIGS.  4 - 9   .  FIG.  10    conceptually illustrates the architecture of a distributed wireless communication device of some embodiments of the invention with the slaves having multiple external communication antennas for communication and beam forming between the slave and the external device. As shown, the slave  1010  has multiple large external antennas  1015  (two are shown but the number can be larger) and a beam former  1020  that is used to communicate with the external device  1025 . Each of the large antennas  1015  has its own PA  1030  and LNA  1035 . The use of beam-forming just makes the effective antenna size bigger but there is one communication channel between the slave and the external device. Although the external device  1025  is shown as having one antenna  1040 , in other embodiments the external device  1025  also has multiple antennas for communicating with the slave  1010 . Alternative embodiments of  FIG.  10    use multiple antennas for internal communication between the slave and the master, as shown in  FIGS.  7 - 9   . In yet other alternative embodiments, a master can communicate with multiple slaves where delays are used for each slave so that multiple slaves beam-form when communicating with the external device. An example of these embodiments is described by reference to  FIG.  14   , below. 
     iii. Slaves with MIMO Implementation 
       FIG.  11    conceptually illustrates the architecture of the distributed wireless communication device of some embodiments of the invention with the slave having multiple external communication antennas together with a MIMO implementation. As shown, the slave  1110  has multiple external communication antennas  1120  together with a MIMO implementation, where each external antenna  1120  has its own communication channel. Only two external antennas  1120  for the slave  1110  are shown but it can also be any number greater than two. In this figure the master  1105  is exploiting the diversity of the slave&#39;s two external antennas  1120  by implementing space-time coding or some other MIMO method in its baseband  1130 . 
     The master  1105  and the slave  1110  of  FIG.  11    have only one internal antenna  1135  and  1140 , respectively. There are different methods to implement the two channels with this one internal antenna configuration. These include having different frequencies for each channel, using spread spectrum where each channel is spread differentially, or time multiplexing between the two channels.  FIG.  11    shows the master  1105  using two different frequencies, f 21  and f 22 . Thus on transmission from the master  1105 , the master uses a separate modem  1150  and  1155  for each antenna channel (two in this example), and their output is combined and transmitted to the slave  1110  using the single internal antenna  1135 . The slave  1110  then uses two mixers (mixer 1 and mixer 2, each with a different clock)  1170  and  1175  to separate the two signals and feed them to the two antennas  1120  for transmission to the external device  1160 . When the external antennas  1120  of the slave  1110  receive from the external device  1160 , the slave  1110  uses two mixers (mixer 3 and mixer 4)  1180  and  1185  to convert their f 1  frequency signals to two different frequencies, f 21  and f 22 , before combining them and transmitting them to the master  1105 . The master  1105  then uses a splitter  1190  (which could be just wires) to separate the two signals for the modems  1150  and  1155  prior to baseband processing. In some alternative embodiments, the slave also has a signal processor for demodulating, decoding, coding, modulating, and reformatting between two different wireless standards. 
     D. Different Placements for Antennas 
       FIGS.  12 ( a )- 12 ( d )  conceptually illustrate four different methods in some embodiments of the invention for placing an electronic device&#39;s radio antenna at a distant location from the device such that the device can communicate with external devices. Examples of this device are a PC, laptop, television set or set-top box. It is desirable to have the antennas near the edges of the display screen or behind the display screen to improve sensitivity and performance. For example, for a Digital TV it is better to have the antennas near the edges of the display or behind the display screen than on circuit boards near the processor of the TV. This is because there is more interference with other circuit components if the antennas are near them. There is also less space on circuit boards for the antennas in terms of optimally laying them out and orienting them. These same arguments are also true for other electronic devices such as a laptop, where it is better to have the antennas near the edges of the display screen or behind the display screen rather than the circuitry under the keyboard. If the antenna is near the edges of the device or its display screen then there is a need for a high-speed connection between the antenna and the rest of the circuitry. 
     As shown in  FIG.  12 ( a ) , the electronic device  1205  has a radio  1210 , baseband  1215  and large antenna  1220  for wireless communication, but the antenna  1220  and radio  1210  are not physically close to the baseband  1215  and the processor  1225  of the device and a cable  1230  is used to connect them. In  FIG.  12 ( b ) , the antenna  1235 , radio and baseband (shown together  1250 ) are distant to the electronic device&#39;s processor  1240  and a USB cable  1245  is used to connect them. 
     In  FIG.  12 ( c ) , the antenna  1255  is distant to the radio, baseband (shown together  1265 ) and electronic device&#39;s processor  1270  and a transmission line  1260  is used to connect to the antenna to the radio. One disadvantage of  FIG.  12 ( c )  is that because the antenna  1260  and the radio&#39;s front-end are far apart there can be a large loss between the two. The cable solution of  FIG.  12 ( a )  is the cheapest solution and the transmission line configuration of  FIG.  12 ( c )  is the most expensive. 
       FIGS.  12 ( a )- 12 ( c )  are wired connectivity solutions. In some situations it is desirable to replace these wired connectivity solutions with a high-speed wireless connectivity solution.  FIG.  12 ( d )  shows the embodiments that replace these wires with a high frequency wireless connection  1275  between a master  1280  and a slave  1285 . Thus, the master and its small antenna  1290  are close to the processor  1295  of the electronic device  1297 , whereas the slave  1285  is further away. The master  1280  communicates wirelessly with distant devices that use frequency f 1  (e.g. 802.11* Wireless LAN 2.4 GHz, 3.6 GHz, 5 GHz, Bluetooth®&#39;s 2.4 GHz ISM band, etc.) by using the slave  1285  as an intermediary. The small antenna  1290  of the master  1280  uses high frequency f 2  (e.g. 60 GHz, 100 GHz, or any other high frequency) to communicate internally with the small antenna  1287  of the slave  1285 . In different embodiments, the master  1280  includes some or all components of the masters described by reference to  FIGS.  4 - 11   , above. Similarly, in different embodiments, the slave  1285  includes some or all components of the slaves described by reference to  FIGS.  4 - 11   , above. 
     The slave  1285  then uses its larger antenna  1289  to communicate externally with the external device (not shown) using the lower f 1  frequency. The slave  1285  places the large antenna  1289  next to the front-end part of the radio (which is included in the slave) that drives the antenna and hence minimizes the loss that can occur between the two. 
     The master  1297 , the slave  1285 , or both can optionally have multiple internal antennas with beam steering as was shown in  FIGS.  7 - 9   . The slave  1285  in some embodiments also has multiple large external antennas for beam-forming (as described above by reference to  FIG.  10   ) or MIMO (as described above by reference to  FIG.  11   ). The master in some embodiments also communicates with multiple slaves at the same time to do beam-forming for communication between the slaves and external devices (as described below by reference to  FIG.  14   ) and MIMO (as described below by reference to  FIG.  15   ). 
     II. Examples of Different Applications of a Distributed Communication System 
     A. Facilitating Communication of an Electronic Device with External Devices 
       FIG.  13    conceptually illustrates an electronic device of some embodiments of the invention that uses the system shown in  FIG.  12 ( d )  for wireless communication with external devices. In  FIG.  13   , an electronic device (such as a TV) has slaves with external antennas placed at optimal locations for wireless connectivity with external devices. As shown, one master  1305  is controlling one or more slaves  1310  out of a matrix of slaves that are placed at optimal locations around the electronic device  1315 . 
     The electronic device  1315  shown could for example be a TV. For simplicity, not all the components of this device are shown. For example suppose that this device includes a set-top box that supports cable, satellite, terrestrial or IP broadcasting. Then the device has a processor for digital media processing, memory (SDRAM, flash/EPROM), display, tuner and video decoder, audio codec and amplifier, video DAC and amplifier, IR decoder, etc. It also has connections for USB, RS232, Ethernet, IRDA, HDMI, 1394, 802.11*, Bluetooth® and other wireless standards. The TV electronics includes a standard processor board. The TV receives content from cable, satellite, or other networks (e.g. home network or Internet either though a wire or from a wireless router/gateway). 
     The electronic device  1315  can then use the master  1305  to communicate wirelessly with external devices  1320  and  1325  by using the slaves  1310  as intermediaries. Thus, the electronic device  1315  acts as a wireless router for external electronic devices  1320  and  1325  around it. Suppose that external device 1  1320  only has a wireless radio that supports standards A (e.g. Bluetooth®). The environment where external device 1  1320  and the electronic device  1315  are located may have a wireless connectivity router that supports wireless radio standard B (e.g. 802.11). But external device 1 can&#39;t use this router because it does not support standard B. The electronic device  1315  in some embodiments, however, uses slaves with different radio standards or some slaves with combo radios. Thus, the electronic device  1315  acts as a multi-standard wireless router or gateway and provides network connectivity for external devices that would otherwise not be able to connect to the network. Variations on  FIG.  13    include the master communicating with several slaves and using beam-forming (as described below by reference to  FIG.  14   ) or MIMO (as described below by reference to  FIG.  15   ), as well as the presence of multiple masters (as described below by reference to  FIGS.  14  and  15   ). 
     In some embodiments the slave&#39;s modem supports encoding for multiple standards. In other embodiments the master addresses and activates multiple slaves (as shown in  FIGS.  13 - 15   ) and each slave supports only one encoding standard or a limited number of encoding standards. Consider  FIG.  13    for the latter case, where the master addresses different slaves for different standards. Each slave (and master) has an address and the master uses control signals on the control channel to activate a particular slave. The packets that are transmitted over the air also have the address of the receiver device. For instance in  FIG.  13   , master  1305  may activate slave S 6  for Wi-Fi (802.11) transmission to external device 1  1320 , and it may activate slave S 4  for Bluetooth® transmission to external device 2  1325 . Here the slaves do most or all the encoding and processing for the standards. This processing is carried out in the slave&#39;s modem  615  (shown in  FIG.  6   ). 
     In yet other embodiments, the slaves also communicate with each other. For instance, in  FIG.  13    master  1305  requires to use slave S 6  for Wi-Fi (802.11) transmission to external device 1  1320 . However, if slave S 6  is not addressable by master  1305  (e.g., because the slave is too distant or because there is an obstacle in between the two), the master uses its control channel to address and activate slave S 5  which is near slave S 6  and can communicate with it. The master uses its HF antenna  1330  and transmits the data to slave S 5 &#39;s HF antenna  1335 . 
     The master also instructs slave S 5  to transmit the data to slave S 6 . In these embodiments the slaves&#39; antennas and modems are bi-directional and can use time duplexing to transmit and receive over the same antenna. Here slave S 5 &#39;s HF antenna  1335  receives the control signals and the data from the master and sends them to the slave&#39;s radio modem  615  (shown in  FIG.  6   ). The slave&#39;s radio modem  615  then uses time duplexing and its HF antenna  1335  to re-transmit the data to slave S 6 &#39;s HF antenna  1340 . Slave S 6  then receives the information from slave S 5  and uses its larger antenna  1345  to make a Wi-Fi (802.11) transmission to external device 1  1320 . 
     B. Beam-Forming 
       FIG.  14    conceptually illustrates a distributed communication device using beam-forming in some embodiments of the invention, where there is one effective communication channel with the external device. Although the electronic equipment shown is a laptop computer, the invention equally applies for other devices such as a tablet, gaming device, TV display, etc. 
     As shown, a number of slaves  1410  are placed far apart from each other around the periphery of the device  1415 , such as in the periphery of the device display for example. As shown, a number of masters  1405  are also placed on the device circuit boards. The slaves  1410  around the periphery also have more room for optimal orientation of antennas, whereas in a conventional centralized wireless system (where the modem and front-end are near each other) the processor and circuit boards of the electronic equipment would limit the possible locations and orientations for the antenna. In the example of  FIG.  14   , master M 2  with modem component uses four slaves S 4 , S 5 , S 6  and S 7  with external antennas  1430  to communicate with an external device. 
     The master is using the same frequency f 2  to communicate with the slaves. There is therefore one communication channel. The master, however, performs beam-forming by changing the RF delays, phases and amplitudes for the slaves in order to maximize the signal received at the external device  1420 . In other embodiments, spatial multiplexing is used where the master splits a high rate signal into multiple lower rate streams and each stream is transmitted to a different slave (e.g. S 4 , S 5 , S 6 , and S 7 ) in the same f 2  frequency channel, and the slaves forward the streams to the external device  1420  using the same frequency f 1 . 
     C. MIMO Implementation 
     Multiple Input Multiple Output (MIMO) wireless systems use multiple antennas and diversity coding to improve system performance. The improvements offered by MIMO are a result of antenna diversity. With diversity coding the signal is coded using space-time coding methods. These coding methods exploit the independent fading characteristics of the multiple antenna signal paths. MIMO systems also offer spatial multiplexing. 
     In a conventional wireless communication system as in  FIG.  3   , however, the front-end and the modem are close together in a single chip, and if there are multiple antennas present they are physically close together. In some embodiments of the invention, the slaves are placed further apart and hence their more distant antennas provide better diversity because of their more independent fading characteristics. 
     One advantage of this method is that by separating the front-end from the master, the multiple antennas of the slaves can be placed further apart and hence provide better antenna diversity since they will experience different multipath and fading characteristics. The greater distance between the antennas of the slaves means less interference between the antennas. Multipath signal interference occurs when the signals are reflected by objects around the receiver. Similar problems include shadowing and fading. Shadowing can be caused by a large obstruction that is along the main signal path between the transmitter and the receiver. Shadowing can produce amplitude and phase changes on a carrier modulated transmitted signal. Fading also describes the distortion that a carrier-modulated signal undergoes as it travels from the transmitter to the receiver. Multipath propagation is one of the main causes of fading since it results in the receiver receiving and superimposing multiple copies of the transmitted signal, each traveling along different paths and experiencing different phase shifts, attenuations and delays. 
       FIG.  15    conceptually illustrates a MIMO implementation of some embodiments of the invention. In these embodiments, the master&#39;s baseband uses MIMO techniques such as space-time coding and there are multiple communication channels. As shown, master M 2   1505  with modem component uses four slaves  1510  (slaves labeled as S 4 , S 5 , S 6 , and S 7 ) to communicate with an external device  1520 . The communication between the master and the slaves, however, use different frequencies (f 24 , f 25 , f 26 , and f 27 ) corresponding to different channels. 
     The master  1505  in some embodiments chooses which slaves and how many slaves out of the set of available slaves to use. For instance, in this example the master chooses the four slaves that provide the best antennas and performance. The master does an initial setup of relationship of antennas. The master then does space-time coding and transmits the codes to the slaves. The slaves use the same frequency f 1  to transmit to the external device, but each slave has a different coding. The external device  1520  then receives the information and performs space-time decoding. 
     In other MIMO embodiments, the slaves use different frequencies to communicate with the external device (e.g. S 4 , S 5 , S 6 , and S 7  use f 14 , f 15 , f 16 , and f 17 , respectively). This reduces interference between the external antennas of the slaves. In these embodiments, the coding becomes space-time-frequency coding where the coding takes into account the frequency as well. In this MIMO configuration it is optional to have beam-forming between the master and each slave if multiple internal antennas are present, but there is no need for beam-forming the four slaves (S 4 , S 5 , S 6 , and S 7 ) as a group to communicate with the external device. It is possible, however, to do beam-forming between individual slaves and the external device provided the individual slaves have multiple external antennas. In  FIGS.  14  and  15    there are several possible modes of operation for the masters to use the slaves to communicate with one or more external device as described, below. 
     1. Single Master Communicates with Single Slave 
     In some embodiments, there are more slaves than are needed but the master can pick the slave that offers the best Bit Error Rate (BER), SNR, power consumption, or Electronic Vector Magnitude (EVM) for communicating with the external device. For example, master M 2   1505  communicates with slave S 6 . This is just a special case of having only one antenna, but here the best antenna from a set of antennas is chosen. The communication between the slave (S 6  in this example) and the external device can also use multiple antennas with beam-forming (as described by reference to  FIG.  10   , above) if they have multiple antennas for communicating with each other. The master can also do MIMO coding (as described by reference to  FIG.  11   , above). 
     2. Single Master Communicates with a Set of Slaves 
     In some embodiments, a master uses a subgroup of slaves to communicate with the external device. For example, master M 2   1505  communicates with slaves S 4 , S 5 , S 6  and S 7  and uses beam-forming between the slaves and the external device, where their signals are combined using phase and there is one effective channel as shown in  FIG.  14   .  FIG.  15    shows a MIMO implementation where master M 2 &#39;s baseband uses space-time coding to communicate with the external device to exploit the spatial diversity of the antennas of the slaves. In this example, if master M 2  drives all 4 slaves at the same time then it can use a different frequency for each slave, where instead of f 2  being the same for all four slaves it could vary for each. For example, master M 2  uses space-time coding in its baseband and f 2  is a different channel for each slave through the use of a different frequency, frequency hopping, PN code spread spectrum, or different data rate with multiplexing. 
       FIG.  15    shows the internal communication frequency between the master and the four slaves as f 24 , f 25 , f 26 , and f 27 . Master M 2   1505  can switch to another group of antennas by talking to e.g., slaves S 1 , S 2 , and S 3 . Master M 2  can also switch to slaves S 8 , S 9  and S 10 . When the sub-set of slaves (e.g. S 4 , S 5 , S 6 , and S 7 ) are close to each other, the master M 2  in some embodiments does beam-forming for communicating over a single channel with the external device (as described by reference to  FIG.  14   , above). When the slaves are far apart and beam-forming is not optimal, the master in some embodiments uses space-time coding to exploit the independent fading characteristics of the distant antennas of the slaves (as described by reference to  FIG.  15   , above). When a slave has multiple antennas, it is possible to use beam-forming for the antennas of that slave in addition to beam-forming for the group of slaves or in addition to space-time coding. 
     The master in some embodiments chooses which group of slaves out of a matrix of slaves to communicate with based on a selection criteria such as optimal Bit Error Rate (BER), SNR, power consumption, or Electronic Vector Magnitude (EVM). In some embodiments, this is done dynamically, where if an obstacle is introduced between one of the slaves, then the master detects the lower performance of that slave and dynamically changes the configuration by switching to another slave. The selection criteria not only determine which slaves are selected but also determine the number of slaves that are selected in a MIMO setting. For example, if the battery level is low the master may select to use 2 slaves instead of the 4 that were used initially when battery levels were higher. 
       FIGS.  14  and  15    show a single HF antenna on the master and on the slave; the beam-forming that was mentioned is between the slaves and the external device. In other embodiments the master, the slave, or both can have multiple HF antennas so that it is also possible to do beam-forming between the master and the slaves, in a manner that was described in  FIGS.  7 ,  8  and  9   . 
     3. Multiple Masters Communicate with Different Sets of Slaves 
     One example of multiple masters communicating with different slaves is when master M 1   1503  communicates with S 1 , S 2  and S 3 ; master M 2   1505  communicates with S 4 , S 5 , S 6 , and S 7 ; and master M 3   1507  communicates with S 8 , S 9  and S 10 . In another embodiment masters M 1 , M 2  and M 3  each use a different frequency to communicate with their group of slaves (i.e. the frequency f 2  is different for M 1 , M 2  and M 3 ). The same discussions in the previous section titled “Single Master Communicates with a Set of Slaves” also apply here. 
     In some embodiments, the slaves in  FIGS.  14  and  15    use different f 1  frequencies and standards for communicating with external devices. For example, S 4 , S 5 , S 6 , and S 7  can have f 1 =2.4 GHz or 3.6 GHz or 5 GHZ for 802.11 Wireless Local Area Network (WLAN) communication with the external device, while S 1 , S 2 , and S 3  can have f 1 =60 GHz for higher frequency directional 60 GHz standards communication, and S 8 , S 9 , and S 10  can have f 1  equal to frequencies for other standards such as cellular (second generation (2G), third generation (3G), fourth generation (4G), etc.), Bluetooth®, 802.11ac, 802.11ad, Worldwide Interoperability for Microwave Access (WiMAX), HD Radio™ and Ultra-wideband standards. In another embodiment some of the masters and slaves are combo-radios and support multiple frequencies and standards. 
     In some embodiments, two master devices also communicate directly with each other without using slaves. For instance, in  FIG.  15    Master M 2  and master M 1  may communicate with each other by using their small HF antennas #0530. This is possible as long as there are no obstacles between the two masters and if the two masters use enough transmission power and are within the transmission range of their HF antennas. The two masters in some embodiments are on the same board (e.g. two ICs on a board communicating wirelessly with each other) while in other embodiments each master is in different physical devices (e.g. laptop master M 2  wirelessly communicating with cell phone master M 1 ) as shown in  FIG.  20   .  FIG.  20    conceptually illustrates two masters directly communicating with each other without using a slave as an intermediary in some embodiments of the invention. Specifically, masters  2005  and  2020  use their HF antennas  2030  and  2035  respectively to communicate with each other. 
     As described above, in some embodiments the master (and the slaves) operate with wireless power (RF or induction), and/or have small batteries that are rechargeable. For instance, in some embodiments a first master  2005  wirelessly powers up (as shown by double arrows  2040 ) a second master  2020  before communicating with the second master wirelessly directly using the HF antennas. For example, a tablet computer (e.g. iPad™) can have a first master  2005  and a cell phone (e.g. iPhone™) can have a second master  2020 . When the cell phone is placed on the tablet computer the first master  2005  in the tablet computer charges the second master  2020  in the cell phone (or the tablet computer has separate a wireless charger that charges the second master) and the two masters communicate wirelessly. 
     The two masters  2005  and  2020  each have their own memory  2080  and  2082 , DSP  2086  and  2088 , and processor (or processing unit)  2092  and  2094  respectively. The two masters therefore do parallel processing in some embodiments for computational tasks and share their memory. The processor  2092  of the first master  2005  in some embodiments is separate from the processor of the tablet while in other embodiments it is the main processor of the tablet. 
     Likewise, the processor  2094  of the second master  2020  in some embodiments is different from the processor of the cell phone while in other embodiments it is the main processor of the cell phone. Some embodiments include a security mechanism where both masters have to be powered up and wirelessly communicating with each other in order for certain data in memory to be accessed and decoded. For example, the tablet device in some embodiments has a document, image, video, audio file, or data stored in its memory. That file can then only be accessed when the cell phone is placed near the tablet and the first master and the second master communicate wirelessly with each other. Likewise, the file may be on the cell phone&#39;s memory and it could only be accessed when the tablet is placed near the cell phone and the first master and the second master communicate wirelessly with each other. Thus, an unauthorized user would have to be in possession of both devices and have knowledge of the security mechanism to be able to view the mentioned data. 
     In addition to security measures this method can also be used to provide board modules that simply attach to a device, such as a laptop computer or a tablet computer, and wirelessly provide additional functionality to the device. Consider the example where the board module has a master that is attached to a sensor  2098  such as an ultrasound sensor or a Near Field Communication (NFC) transceiver. Both the master and the sensor are powered up wirelessly. This board module is then attached or placed near a computer (e.g. laptop or a tablet). The board&#39;s master and sensor receive their power wirelessly from the computer or from the computer&#39;s master (e.g. RF or induction). The board&#39;s sensor can then use the board&#39;s master to wirelessly communicate with the computer&#39;s master and provide additional functionality to the computer (e.g. ultrasound sensing or NFC reader). 
       FIG.  16    conceptually illustrates a process  1600  for the master to dynamically change the system configuration to optimize system performance in some embodiments of the invention. As shown, the process chooses (at  1605 ) an initial system configuration. System configuration parameters include the number and set of active slaves, mode of the channel between the master and the slave(s) (single frequency channel, MIMO, etc.), coding for each slave if MIMO is used, beam-forming between the master and the slaves (on or off), etc. 
     The process then determines (at  1610 ) whether the communication session is finished or whether there is more data to transmit/receive. When the process determines that the session has ended, the process exits. Otherwise, the process monitors (at  1615 ) the system performance (e.g., by using the master&#39;s processor and baseband to monitor the performance). System performance parameters include capacity of channel between the master and the slave(s), packet error rate, Bit Error Rate (BER), feedback from the slaves as to how much signal strength they receive, power consumption and battery levels of the slaves and the master, etc. 
     Next, the process changes (at  1620 ) (e.g., by using the master&#39;s processor and baseband) system configuration in response to the monitored system performance. The process in some embodiments addresses slaves independently and turns some slaves on while turning other slaves off in order to improve performance. The process in some embodiments changes the mode of the channel between the master and the slaves (e.g. changes single frequency channel to MIMO, or vice versa, changes the MIMO coding of slaves, change the state of the beam-forming between the master and the slaves (on to off, or vice versa), etc.). The process then proceeds to  1610  and the process of monitoring system performance and changing system configuration continues until the communication session ends. In some embodiments, system configuration also includes parameters between the slaves and the external device such as beam-forming between the slaves and the external device to be turned on or off. 
     D. Gaming Application 
     Some embodiments are applicable to specific applications that require sensing data measurements. One such application is gaming. Video game consoles from various companies (Sony®, Microsoft™, Nintendo®) have a game console and one or more remotes. The remotes for these products typically use infrared technology and/or short-range wireless technologies such as Bluetooth® to communicate with the game console. Some remotes (e.g. Nintendo® V) also use gyroscopes to sense motion and acceleration. However, these remotes do not provide accurate position information. One application for some embodiments of the invention is to provide accurate sensing information of a gaming remote to the game console in order to provide a richer gaming experience. The sensing information can include parameters such as position tracking, relative movement, and acceleration. 
       FIG.  17    conceptually illustrates an implementation for a gaming application in some embodiments of the invention. In this gaming application, the external device  1720  is a video gaming remote, and the masters  1705  (only one is shown for simplicity) and the slaves  1710  are mounted on a consumer electronics device  1715  with a display such as a TV or a PC monitor. The game controller  1725  is connected to the electronics device  1715 . In some embodiments, the game controller  1725  is integrated into the electronics device with the display. In yet other embodiments, the game controller  1725  is connected to or its functionality resides on a server or cloud computing set-up on the Internet. 
     If the frequency f 1  is also a high frequency (i.e., in the same range as f 2  but possibly a different frequency, e.g. f 2  is 60 GHz and f 1  is 50 Ghz or 100 GHz), then the external communication antennas  1730  of the slave  1710  that communicate with the gaming remote  1720  are small, and hence a large matrix of slaves  1710  can be mounted on the display. The slaves can be mounted behind the display in a matrix or some irregular pattern and their external antennas can point in a uniform direction or different directions. The slaves in some embodiments have dedicated radios for wireless standards such as cellular (second generation (2G), third generation (3G), fourth generation (4G), etc.), Bluetooth®, Worldwide Interoperability for Microwave Access (WiMAX), HD Radio™ and Ultra-wideband standards. Some of the slaves can also be combo radios, where the radios support different frequencies and standards. 
     When the gaming remote  1720  points to the screen, the antennas of the slaves with the strongest signal track the location that the gaming remote is pointing to and give tracking information to the master which gives it to the gaming controller. In some embodiments the remote  1720  is small enough that it is wearable on human fingers. The remote in some embodiments also operates with wireless power or has small batteries that are rechargeable (e.g., with wireless power). In multi-player gaming applications there can be more than one remote  1720 . In some embodiments, there are more than one master (as shown in  FIGS.  14  and  15   ). 
     The processing of the information is also distributed between the slaves, the master (or masters if there are more than one) and the gaming controller. Some of the processing is done at the slave. For example, consider the case where two game users are using two remotes which employ different f 1  frequencies to communicate with the slaves. When the users point their remotes to the same slave, the slave can adapt its filtering to communicate with one remote, or the other, or both. The master also does its own processing such as relative range calculations, location of each remote, and passes that information to the game controller. The game controller then does high-level game decisions. 
     E. Other Applicable Standards 
     The 60 GHz wireless standard is one example of using higher frequencies for implementing this invention. There are several standards bodies that are using high frequencies such as 60 GHz. These include WirelessHD, WiGig, and WiFi IEEE 802.11ad. In the U.S. the 60 GHz spectrum band can be used for unlicensed short range data links (1.7 km) with data throughputs up to 2.5 Gbits/s. Higher frequencies such as the 60 GHz spectrum experience strong free space attenuation. The smaller wavelength of such high frequencies also enables the use of small high gain antennas with small beam widths. The combination of high attenuation and high directive antenna beams provides better frequency reuse so that the spectrum can be used more efficiently for point-to-multipoint communications. For example, a larger number of directive antennas and users can be present in a given area without interfering with one another, compared to less directive antennas at lower frequencies. Small beam width directive antennas also confine the electromagnetic waves to a smaller space and therefore limit human exposure. The higher frequencies also provide more bandwidth and allow more information to be wirelessly transmitted. Thus, the same antenna can be used for power generation and communication. 
     III. Electronic System 
       FIG.  18    conceptually illustrates an electronic system  1800  with which some embodiments of the invention are implemented. The electronic system  1800  may be a computer (e.g., a desktop computer, personal computer, tablet computer, etc.), phone, PDA, or any other sort of electronic or computing device. Such an electronic system includes various types of computer readable media and interfaces for various other types of computer readable media. Electronic system  1800  in some embodiments includes a bus  1805 , processing unit(s)  1810 , a graphics processing unit (GPU)  1815 , a system memory  1820 , a network  1825 , a read-only memory  1830 , a permanent storage device  1835 , input devices  1840 , and output devices  1845 . 
     The bus  1805  collectively represents all system, peripheral, and chipset buses that communicatively connect the numerous internal devices of the electronic system  1800 . For instance, the bus  1805  communicatively connects the processing unit(s)  1810  with the read-only memory  1830 , the GPU  1815 , the system memory  1820 , and the permanent storage device  1835 . 
     From these various memory units, the processing unit(s)  1810  retrieves instructions to execute and data to process in order to execute the processes of the invention. The processing unit(s) may be a single processor or a multi-core processor in different embodiments. Some instructions are passed to and executed by the GPU  1815 . The GPU  1815  can offload various computations or complement the image processing provided by the processing unit(s)  1810 . In some embodiments, such functionality can be provided using CoreImage&#39;s kernel shading language. 
     The read-only-memory (ROM)  1830  stores static data and instructions that are needed by the processing unit(s)  1810  and other modules of the electronic system. The permanent storage device  1835 , on the other hand, is a read-and-write memory device. This device is a non-volatile memory unit that stores instructions and data even when the electronic system  1800  is off. Some embodiments of the invention use a mass-storage device (such as a magnetic or optical disk and its corresponding disk drive) as the permanent storage device  1835 . 
     Other embodiments use a removable storage device (such as a floppy disk, flash memory device, etc., and its corresponding disk drive) as the permanent storage device. Like the permanent storage device  1835 , the system memory  1820  is a read-and-write memory device. However, unlike storage device  1835 , the system memory  1820  is a volatile read-and-write memory, such a random access memory. The system memory  1820  stores some of the instructions and data that the processor needs at runtime. In some embodiments, the invention&#39;s processes are stored in the system memory  1820 , the permanent storage device  1835 , and/or the read-only memory  1830 . For example, the various memory units include instructions for processing multimedia clips in accordance with some embodiments. From these various memory units, the processing unit(s)  1810  retrieves instructions to execute and data to process in order to execute the processes of some embodiments. 
     The bus  1805  also connects to the input and output devices  1840  and  1845 . The input devices  1840  enable the user to communicate information and select commands to the electronic system. The input devices  1840  include alphanumeric keyboards and pointing devices (also called “cursor control devices”), cameras (e.g., webcams), microphones or similar devices for receiving voice commands, etc. The output devices  1845  display images generated by the electronic system or otherwise output data. The output devices  1845  include printers and display devices, such as cathode ray tubes (CRT) or liquid crystal displays (LCD), as well as speakers or similar audio output devices. Some embodiments include devices such as a touchscreen that function as both input and output devices. 
     Finally, as shown in  FIG.  18   , bus  1805  also couples electronic system  1800  to a network  1825  through a network adapter (not shown). In this manner, the computer can be a part of a network of computers (such as a local area network (“LAN”), a wide area network (“WAN”), or an Intranet, or a network of networks, such as the Internet. Any or all components of electronic system  1800  may be used in conjunction with the invention. 
     Many of the above-described features and applications are implemented as software processes that are specified as a set of instructions recorded on a computer readable storage medium (also referred to as computer readable medium, machine readable medium, machine readable storage). When these instructions are executed by one or more computational or processing unit(s) (e.g., one or more processors, cores of processors, or other processing units), they cause the processing unit(s) to perform the actions indicated in the instructions. Examples of computer readable media include, but are not limited to, CD-ROMs, flash drives, random access memory (RAM) chips, hard drives, erasable programmable read only memories (EPROMs), electrically erasable programmable read-only memories (EEPROMs), etc. The computer readable media does not include carrier waves and electronic signals passing wirelessly or over wired connections. 
     In this specification, the term “software” is meant to include firmware residing in read-only memory or applications stored in magnetic storage which can be read into memory for processing by a processor. Also, in some embodiments, multiple software inventions can be implemented as sub-parts of a larger program while remaining distinct software inventions. In some embodiments, multiple software inventions can also be implemented as separate programs. Finally, any combination of separate programs that together implement a software invention described here is within the scope of the invention. In some embodiments, the software programs, when installed to operate on one or more electronic systems, define one or more specific machine implementations that execute and perform the operations of the software programs. 
     Some embodiments include electronic components, such as microprocessors, storage and memory that store computer program instructions in a machine-readable or computer-readable medium (alternatively referred to as computer-readable storage media, machine-readable media, or machine-readable storage media). Some examples of such computer-readable media include RAM, ROM, read-only compact discs (CD-ROM), recordable compact discs (CD-R), rewritable compact discs (CD-RW), read-only digital versatile discs (e.g., DVD-ROM, dual-layer DVD-ROM), a variety of recordable/rewritable DVDs (e.g., DVD-RAM, DVD-RW, DVD+RW, etc.), flash memory (e.g., SD cards, mini-SD cards, micro-SD cards, etc.), magnetic and/or solid state hard drives, read-only and recordable Blu-Ray® discs, ultra density optical discs, any other optical or magnetic media, and floppy disks. The computer-readable media may store a computer program that is executable by at least one processing unit and includes sets of instructions for performing various operations. Examples of computer programs or computer code include machine code, such as is produced by a compiler, and files including higher-level code that are executed by a computer, an electronic component, or a microprocessor using an interpreter. 
     While the above discussion primarily refers to microprocessor or multi-core processors that execute software, some embodiments are performed by one or more integrated circuits, such as application specific integrated circuits (ASICs) or field programmable gate arrays (FPGAs). In some embodiments, such integrated circuits execute instructions that are stored on the circuit itself. In addition, some embodiments execute software stored in programmable logic devices (PLDs), ROM, or RAM devices. 
     As used in this specification and any claims of this application, the terms “computer”, “server”, “processor”, and “memory” all refer to electronic or other technological devices. These terms exclude people or groups of people. For the purposes of the specification, the terms display or displaying means displaying on an electronic device. As used in this specification and any claims of this application, the terms “computer readable medium,” “computer readable media,” and “machine readable medium” are entirely restricted to tangible, physical objects that store information in a form that is readable by a computer. These terms exclude any wireless signals, wired download signals, and any other ephemeral signals. 
     While the invention has been described with reference to numerous specific details, one of ordinary skill in the art will recognize that the invention can be embodied in other specific forms without departing from the spirit of the invention. In addition, a number of the figures (e.g.,  FIG.  16   ) conceptually illustrate processes. The specific operations of these processes may not be performed in the exact order shown and described. The specific operations may not be performed in one continuous series of operations, and different specific operations may be performed in different embodiments. Furthermore, the process could be implemented using several sub-processes, or as part of a larger macro process. Thus, one of ordinary skill in the art would understand that the invention is not to be limited by the foregoing illustrative details, but rather is to be defined by the appended claims. 
     While the invention has been described with reference to numerous specific details, one of ordinary skill in the art will recognize that the invention can be embodied in other specific forms without departing from the spirit of the invention. Thus, one of ordinary skill in the art would understand that the invention is not to be limited by the foregoing illustrative details, but rather is to be defined by the appended claims.