Patent Application
20150049793
1. Field
The present invention relates generally to interfacing a digital module and a radio-frequency module of a wireless communication device.
2. Background
Wireless communication systems are widely deployed to provide various types of communication content such as voice, video, data, and so on. These systems may be multiple-access systems capable of supporting simultaneous communication of multiple wireless communication devices with one or more base stations.
A wireless communication device commonly incorporates multiple components. For example, a wireless communication device may include a power module, a digital module including one or more processors, and a radio-frequency (RF) module including one or more transceivers. As will be understood by a person having ordinary skill in the art, a baseband processor within a digital module may interface with one or more components of an RF module. The baseband processor may generate and convey baseband signals in digital format. Further, a transmitter within the RF module may receive the baseband signals from the baseband processor and up-convert the baseband signal to RF using one or more mixers. The transmitter may then amplify the RF signal, via a driver amplifier and power amplifiers, for transmission via an antenna.
In current RF transceivers, 1-3 digital interface pins are assigned to Global System for Mobile Communications (GSM) phase data, which is transmitted from digital module to an RF transceiver during operation in a GSM mode. Further, in low-tier markets, the reduction of die area is extremely important. In devices with wafer level package (WLP), the number of I/Os (pins) is limited by the die area. Therefore, pin reduction is of utmost importance
A need exists for reducing a number of pins within a wireless communication device. More specifically, a need exists for embodiments related to a digital to RF interface that enables a reduction of pins on each of a digital module and an RF module of a wireless communication device.
The detailed description set forth below in connection with the appended drawings is intended as a description of exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention can be practiced. The term “exemplary” used throughout this description means “serving as an example, instance, or illustration,” and should not necessarily be construed as preferred or advantageous over other exemplary embodiments. The detailed description includes specific details for the purpose of providing a thorough understanding of the exemplary embodiments of the invention. It will be apparent to those skilled in the art that the exemplary embodiments of the invention may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the novelty of the exemplary embodiments presented herein.
As noted above, wireless communication networks are widely deployed to provide various communication services such as voice, video, packet data, messaging, broadcast, etc. These wireless networks may be multiple-access networks capable of supporting multiple users by sharing the available network resources. Examples of such multiple-access networks include Code Division Multiple Access (CDMA) networks, Time Division Multiple Access (TDMA) networks, Frequency Division Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA) networks, and Single-Carrier FDMA (SC-FDMA) networks. A CDMA network may implement a radio technology such as Universal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. A TDMA network may implement a radio technology such as Global System for Mobile Communications (GSM). An OFDMA network may implement a radio technology such as Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDMA, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are new releases of UMTS that use E-UTRA.
In the transmit path, data processor 110 processes data to be transmitted and provides an analog output signal to transmitter 130. Within transmitter 130, the analog output signal is amplified by an amplifier (Amp) 132, filtered by a lowpass filter 134 to remove images caused by digital-to-analog conversion, amplified by a VGA 136, and upconverted from baseband to RF by a mixer 138. The upconverted signal is filtered by a filter 140, further amplified by a driver amplifier 142 and a power amplifier 144, routed through switches/duplexers 146, and transmitted via an antenna 148.
In the receive path, antenna 148 receives signals from base stations and/or other transmitter stations and provides a received signal, which is routed through switches/duplexers 146 and provided to receiver 150. Within receiver 150, the received signal is amplified by an LNA 152, filtered by a bandpass filter 154, and downconverted from RF to baseband by a mixer 156. The downconverted signal is amplified by a VGA 158, filtered by a lowpass filter 160, and amplified by an amplifier 162 to obtain an analog input signal, which is provided to data processor 110.
Data processor 110 may perform various functions for wireless device 100, e.g., processing for transmitted and received data. Memory 112 may store program codes and data for data processor 110. Data processor 110 may be implemented on one or more application specific integrated circuits (ASICs) and/or other ICs.
RF module 220 may include various circuits in a transceiver, e.g., all circuits in transceiver 120 in
Exemplary embodiments, as described herein, are directed to devices and methods related to an interface between a digital module and an RF module of a device. According to one exemplary embodiment, a device may include a digital module configured to output at least one constant-envelope modulated (i.e., phase of frequency modulated) signal. As a more specific example, the digital module configured to output at least one analog signal comprising transmit signal phase information while operating in Global System for Mobile Communication (GSM) mode. The device may further include a RF module coupled to the digital module and configured to receive the at least one analog signal and generate one or more digital bits in response to receipt of the at least one analog signal.
According to another exemplary embodiment, the present invention includes methods for conveying transmit signal phase information from a digital module to an RF module. Various embodiments of such a method may include conveying at least one constant-envelope modulated (i.e., phase of frequency modulated) signal from the digital module to the RF module. As a more specific example, the method may include conveying at least one analog signal comprising phase information from a digital module while operating in Global System for Mobile Communication (GSM) mode. The method may also include receiving the at least one analog signal at the RF module. Further, the method may include generating one or more digital bits from the at least one analog signal at the RF module.
Other aspects, as well as features and advantages of various aspects, of the present invention will become apparent to those of skill in the art though consideration of the ensuing description, the accompanying drawings and the appended claims.
In addition, a constant-envelope modulated (e.g., phase or frequency modulated) signal may be conveyed from digital module 352 to RF module 354 via another DAC. As a more specific example, while operating in GSM mode, phase data of the transmit signal may be conveyed from digital module 352 to RF module 354 via the another DAC. It is noted that the DAC used to convey the phase data may comprise a DAC that was previously unused (i.e., idle) (e.g., during conventional GSM operation). Accordingly, exemplary embodiments of the present invention may relate to sharing a DAC pin of digital module 352 for various operating modes (i.e., GSM, CDMA, etc.). Stated another way, for example only, a DAC pin, which was configured for use in a CDMA mode and idle during GSM operation, may now be used in both modes.
In this exemplary embodiment, the two most significant bits of DAC 512 may receive the phase information and the remaining N−2 bits may be coupled to a ground voltage when phase information is being transmitted. Further, DAC 512 may receive the digital bits including the phase information and generate at least one analog signal including the phase information. More specifically, as one example, DAC 512 may output a differential analog output (i.e., signals Ip and In) having a value that changes based on the digital bits received at the input of DAC 512. It is noted that DAC 512 may comprise, for example only, a current DAC or a voltage DAC. In non-GSM mode, the same DAC 512 together with another DAC could be used for I/Q analog transmission.
With reference to
Also, for example, if the input of DAC 512 is “01”, signal Ip may comprise a value of
FS/3 and, signal In may comprise a value of (2/3)FS. Further, a DAC input of “10” provides an output of 2FS/3 (i.e., if the input of DAC 512 is “10”, the output of DAC 512 is FS*(2/3)). Furthermore, for example, if the input of DAC 512 is “10”, signal Ip may comprise a value of (2/3)FS, and signal In may comprise a value of FS/3. Moreover, a DAC input of “11” provides an output of FS (i.e., if the input of DAC 512 is “11”, the output of DAC 512 is FS). Additionally, for example, if the input of DAC 512 is “11”, signal Ip may comprise a value of FS, and signal In may comprise a value of zero.
Moreover, RF module 504, as illustrated in
Upon receipt of output signals T0, T1, and T2, thermometer-to-binary converter 524 may generate a binary representation of output signals T0, T1, and T2. For example, thermometer-to-binary converter 524 may generate a 2-bit binary representation of output signals T0, T1, and T2. More specifically, if a thermometer code for output signals T0, T1, and T2 is “000”, thermometer-to-binary converter 524 may generate a “00”. If a thermometer code for output signals T0, T1, and T2 is “001”, thermometer-to-binary converter 524 may generate a “01”. If a thermometer code for output signals T0, T1, and T2 is “011”, thermometer-to-binary converter 524 may generate a “10”. Further, if a thermometer code for output signals T0, T1, and T2 is “111”, thermometer-to-binary converter 524 may generate a “11”. RF module 504 may also include a clock data recovery circuit (CDR) 526 and a flip-flop 528. It is noted that CDR 526 may be configured to extract clock information from the received stream of bits. This clock information may then be used to re-synchronize the decoded binary bits.
As illustrated in the exemplary embodiment of
A source of transistor M4 and a source of transistor M5 are coupled together, and a drain of transistor M5 is coupled to a drain of transistor M6. A first output signal TO may be conveyed at a node A coupled between the drain of transistor M5 and the drain of transistor M6. A source of transistor M6 is coupled to ground voltage GRND, and a gate of transistor M6 is coupled to a gate of transistor M2.
Further, ADC 520 includes a transistor M7 having a source coupled to a source of transistor M5, a gate coupled to a gate of transistor M5, and a drain coupled to a drain of a transistor M8. A second output signal T1 may be conveyed at a node B coupled between the drain of transistor M7 and the drain of transistor M8. A source of transistor M8 is coupled to ground voltage GRND, and a gate of transistor M8 is coupled to a gate of transistor M6. Additionally, ADC 520 includes a transistor M9 having a source coupled to a source of transistor M7, a gate coupled to a gate of transistor M7, and a drain coupled to a drain of a transistor M10. A third output signal T2 may be conveyed at a node C coupled between the drain of transistor M9 and the drain of transistor M10. A source of transistor M10 is coupled to ground voltage GRND, and a gate of transistor M10 is coupled to a gate of transistor M8. It is noted that
It is noted that digital module 502 may include at least one additional DAC 513. More specifically, during, for example only, GSM operation, additional transmit signal data (i.e., amplitude data) may be conveyed from digital module 502 to RF module 504 via DAC 513 of digital module 502.
Those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.
Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the exemplary embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the exemplary embodiments of the invention.
The various illustrative logical blocks, modules, and circuits described in connection with the exemplary embodiments disclosed herein may be implemented or performed with a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.
In one or more exemplary embodiments, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another.
A storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.
The previous description of the disclosed exemplary embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these exemplary embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the exemplary embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
