Patent Application
20220393929
The disclosed teachings relate to digital interfaces between baseband and radiofrequency modules in radio communications.
Modern wireless communication systems typically separate baseband (BB) and radiofrequency (RF) functions into distinct integrated circuit (IC) chips. The amount of information exchanged between the BB and RF chips has increased in recent years due to improvements in radio system transmission capabilities. With increased uplink/downlink throughput, the interface to exchange data between BB and RF chips is more efficient in a digital format.
A trend to standardize the digital interface has emerged. For example, SerDes is standardized technology for data transmission over a single line or a differential pair where data is converted between serial data and parallel interfaces in each direction in order to minimize the number of I/O pins and interconnects. DigRF specifications describe the logical, electrical, and timing characteristics of a digital interface to allow physical implementation of the interface for mobile devices. M-PHY is a high-speed data communications physical layer protocol standard that is targeted at the needs of mobile multimedia devices.
With the introduction of 4G/5G telecommunications, the throughput on the digital interface is pushed even higher. To accommodate the ever-increasing demand for throughput, the digital interface implements multiple lanes for data transfers. Nevertheless, the required high throughput has brought challenges to both physical design of the interface and power consumption by power sensitive devices such as mobile phones.
Embodiments of the present technology will be described and explained through the use of the accompanying drawings.
Various features of the technologies described herein will become more apparent to those skilled in the art from a study of the Detailed Description in conjunction with the drawings. Embodiments are illustrated by way of example and not limitation in the drawings, in which like references may indicate similar elements. While the drawings depict various embodiments for the purpose of illustration, those skilled in the art will recognize that alternative embodiments may be employed without departing from the principles of the technologies. Accordingly, while specific embodiments are shown in the drawings, the technology is amenable to various modifications.
The disclosed solution includes a digital interface between baseband (BB) and radiofrequency (RF) modules. The term “module” refers to a component part that can be embodied as hardware, software, or a combination of both. An example of a module in the context of a BB-RF interface includes an integrated circuit (IC) semiconductor device (e.g., chip) or component of the IC chip. The disclosed digital interface minimizes or reduces throughput needed to transfer digital data efficiently between BB and RF modules. The reduced throughput improves over existing digital interfaces by, among other things, reducing power consumption. The reduction in throughput results by transferring data through the digital interface in the frequency domain rather than in the time domain. The transfer of frequency domain data is enabled with a circuit architecture that has certain components in the RF module, which are typically found on the BB module.
The architecture reflects advances in process technology (also referred to as “process node”), which refers to specific semiconductor manufacturing processes and associated design rules. Generally, a smaller process technology corresponds to smaller feature size, producing smaller transistors which are both faster and more power-efficient. Recent process technology such as 22 nm, 16 nm, 14 nm, 10 nm, 6 nm, and 2 nm refer to specific generations of chips. In typical BB-RF circuit design, the RF module is more physically compact compared to the BB module. Given the reduction in process technology, relatively larger components such as a fast Fourier transfer (FFT) module (e.g., engine) and an inverse fast Fourier transfer (IFFT) engine can be placed on an RF IC chip rather than a BB IC chip while keeping the RF module physically compact.
In contrast, conventional systems pass time domain data through the digital interface. The time domain data carries excessive amounts of overhead because the total amount of bits transferred through the digital interface remains constant despite only a lesser amount carrying meaningful data (e.g., the total amount includes empty tones and a cyclic prefix). As such, there is proportionally more overhead as the meaningful amount of data decreases in the time domain. On the other hand, the total bits scale in the frequency domain because the overhead of time domain is absent.
More specifically, in the time domain, the throughput is consistently high regardless of the number of resource blocks (RB) that are allocated for uplink/downlink data. The RB is the smallest unit of resources that can be allocated for uplink/downlink data, where each block carries 12 consecutive tones. A base station configures RB allocation for uplink/downlink. For a full RB allocation configuration, the overhead of a sample is 33%. For a partial RB allocation, overhead can be more than 273 times the allocated RB. To accommodate a high peak throughput, existing solutions in the time domain employ multiple data lanes for the digital interface, which significantly increase power consumption and require a larger board area for the digital interface. Hence, the disclosed digital interface can be physically more compact with fewer lanes compared to existing digital interfaces because the prior need for higher throughput is reduced.
The disclosed digital interface overcomes the aforementioned drawbacks. For example,
The symbol information that is maintained at the BB module 104 is transferred to RF module 104 at different points in time (e.g., periodically, as needed). For example, the symbol information can be transferred in response to changes of the base station, such that the modules of the RF module 106 are updated based on the changes. The symbol boundary information includes control mechanisms established for the RF module 106 to identify a symbol boundary and a beginning of symbol in the time domain. The RB configuration information is a function of the symbol map 110, which needs to know which RB are allocated for uplink/downlink, to map symbols to the allocated RB. The timing advance refers to, for example, a signal of the base station to indicate a point in time when a mobile device (e.g., user equipment) should stop transmitting data.
The components of the RF module 106 include an optional symbol map 110, an FFT engine 116, an IFFT engine 118, a cyclic prefix (CP) insertion module 120, a time domain gain control module 122, a CP removal module 124, and a frequency domain gain control module 126. The FFT engine 116 and IFFT engine 118 are disposed on the RF module 106 instead of being disposed on a BB module as in conventional digital interfaces. The FFT engine 118 is configured to convert time domain data (e.g., samples) to frequency domain data. The IFFT engine 118 is configured to convert frequency domain samples to time domain samples. Therefore, the conversion between time domain and frequency domain samples occurs at the RF module 106.
The architecture 100 provides operational improvements over conventional technology. For example,
At 204A, the symbol map 110 is at the BB module 104 and maps the frequency domain uplink data to inputs of the IFFT engine 118. For example, the symbol map 110 can map symbols to input tones of the IFFT engine 118 (as a symbol index), which further reduces throughput through the digital interface compared to passing the unmapped symbol data. The mapping is determined based in part on symbol information obtained from the symbol information module 112. Examples of the symbol information include symbol boundary information and RB configuration information. The RB configuration information indicates which RB are allocated for uplink data. As such, the symbol map 110 can map symbols to the appropriate RB that are allocated for uplink.
At 206A, the frequency domain uplink data is transferred through the digital interface 102 to the RF module 104. At 208A, if the symbol map 110 is at the RF module 106, the frequency domain uplink data that is transferred through the digital interface 102 is then mapped to input tones of the IFFT engine 118. Either way, frequency domain uplink data is passed through the digital interface 102 instead of time domain uplink data, which significantly reduces the throughput over the digital interface 102. Moreover, in the event that only some tones for certain symbols are used for uplink data, throughput is reduced because the total bits per symbol scale in the frequency domain, unlike the fixed amount of total bits per symbol in the time domain.
At 210A, the IFFT engine 118 converts the frequency domain uplink data to time domain uplink data. At 212A, the CP insertion module 120 is configured to then insert a CP in a time domain uplink data. The position in the time domain uplink data for inserting the CP is determined based in part on the symbol boundary information and a timing advance obtained from the symbol information module 112 at the BB module 104.
TABLE 1 includes examples that demonstrate improvements measured as a throughput ratio of time and frequency. In the examples, data is transferred at 100 MHz CP-s-OFDM. Two examples are considered: max 273 RB and min 1 RB. Every sample (time or frequency domain) is assumed to have total 24 bits (12 bit I+12 bit Q). For frequency domain sample, RB configuration info is assumed to use 32 bits.
TABLE 1 illustrates the consequences that result from keeping time domain total bits per symbol constant, regardless of the number of RB. As shown, there is proportionally more overhead as the number of RB decrease. On the other hand, the frequency domain total bits per symbol scales with the number of RB because the overhead required to maintain a fixed number of total bits is absent. As such, as illustrated in the table, at least a 33% throughput saving is achieved for full RB (273) allocation. More throughput saving is achieved for a smaller number of RB in the frequency domain because the overhead in the time domain does not scale down.
Therefore, the proposed solution includes a throughput savings by avoiding the burden of constantly supporting high throughput.
In the illustrated embodiment, the processing system 300 includes one or more processors 302, memory 304, a communication device 306, and one or more input/output (I/O) devices 308, all coupled to each other through an interconnect 310. The interconnect 310 can be or include one or more conductive traces, buses, point-to-point connections, controllers, adapters and/or other conventional connection devices. Each of the processor(s) 302 can be or include, for example, one or more general-purpose programmable microprocessors or microprocessor cores, microcontrollers, application specific integrated circuits (ASICs), programmable gate arrays, or the like, or a combination of such devices.
The processor(s) 302 control the overall operation of the processing system 300. Memory 304 can be or include one or more physical storage facilities, which can be in the form of random-access memory (RAM), read-only memory (ROM) (which can be erasable and programmable), flash memory, miniature hard disk drive, or other suitable type of storage device, or a combination of such devices. Memory 304 can store data and instructions that configure the processor(s) 302 to execute operations in accordance with the techniques described above. The communication device 306 can be or include, for example, an Ethernet adapter, cable modem, Wi-Fi adapter, cellular transceiver, Bluetooth transceiver, or the like, or a combination thereof. Depending on the specific nature and purpose of the processing system 300, the I/O devices 308 can include devices such as a display (which can be a touch screen display), audio speaker, keyboard, mouse or other pointing device, microphone, camera, etc.
While processes or blocks are presented in a given order, alternative embodiments can perform routines having steps or employ systems having blocks, in a different order, and some processes or blocks can be deleted, moved, added, subdivided, combined and/or modified to provide alternative or sub-combinations, or can be replicated (e.g., performed multiple times). Each of these processes or blocks can be implemented in a variety of different ways. In addition, while processes or blocks are at times shown as being performed in series, these processes or blocks may instead be performed in parallel, or can be performed at different times. When a process or step is “based on” a value or a computation, the process or step should be interpreted as based at least on that value or that computation.
Software or firmware to implement the techniques introduced here can be stored on a machine-readable storage medium and can be executed by one or more general-purpose or special-purpose programmable microprocessors. A “machine-readable medium”, as the term is used herein, includes any mechanism that can store information in a form accessible by a machine (a machine can be, for example, a computer, network device, cellular phone, personal digital assistant (PDA), manufacturing tool, any device with one or more processors, etc.). For example, a machine-accessible medium includes recordable/non-recordable media (e.g., read-only memory (ROM), random-access memory (RAM), magnetic disk storage media, optical storage media, flash memory devices), etc.
Note that any and all of the embodiments described above can be combined with each other, except to the extent that it may be stated otherwise above, or to the extent that any such embodiments might be mutually exclusive in function and/or structure. Although the present invention has been described with reference to specific exemplary embodiments, it will be recognized that the invention is not limited to the embodiments described but can be practiced with modification and alteration within the spirit and scope of the disclosed embodiments. Accordingly, the specification and drawings are to be regarded in an illustrative sense rather than a restrictive sense.
Physical and functional components (e.g., devices, engines, modules, and data repositories) associated with processing system 300 can be implemented as circuitry, firmware, software, other executable instructions, or any combination thereof. For example, the functional components can be implemented in the form of special-purpose circuitry, in the form of one or more appropriately programmed processors, a single board chip, a field programmable gate array, a general-purpose computing device configured by executable instructions, a virtual machine configured by executable instructions, a cloud computing environment configured by executable instructions, or any combination thereof. For example, the functional components described can be implemented as instructions on a tangible storage memory capable of being executed by a processor or other integrated circuit chip. The tangible storage memory can be computer-readable data storage. The tangible storage memory can be volatile or non-volatile memory. In some embodiments, the volatile memory can be considered “non-transitory” in the sense that it is not a transitory signal. Memory space and storage described in the figures can be implemented with the tangible storage memory as well, including volatile or non-volatile memory.
Each of the functional components can operate individually and independently of other functional components. Some or all of the functional components can be executed on the same host device or on separate devices. The separate devices can be coupled through one or more communication channels (e.g., wireless or wired channel) to coordinate their operations. Some or all of the functional components can be combined as one component. A single functional component can be divided into sub-components, each sub-component performing separate method steps or a method step of the single component.
In some embodiments, at least some of the functional components share access to a memory space. For example, one functional component can access data accessed by or transformed by another functional component. The functional components can be considered “coupled” to one another if they share a physical connection or a virtual connection, directly or indirectly, allowing data accessed or modified by one functional component to be accessed in another functional component. In some embodiments, at least some of the functional components can be upgraded or modified remotely (e.g., by reconfiguring executable instructions that implement a portion of the functional components). Other arrays, systems and devices described above can include additional, fewer, or different functional components for various applications.
Aspects of the disclosed embodiments can be described in terms of algorithms and symbolic representations of operations on data bits stored in memory. These algorithmic descriptions and symbolic representations generally include a sequence of operations leading to a desired result. The operations require physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electric or magnetic signals that are capable of being stored, transferred, combined, compared, and otherwise manipulated. Customarily, and for convenience, these signals are referred to as bits, values, elements, symbols, characters, terms, numbers, or the like. These and similar terms are associated with physical quantities and are merely convenient labels applied to these quantities.
Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise,” “comprising,” and the like are to be construed in an inclusive sense, as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to.” As used herein, the terms “connected,” “coupled,” or any variant thereof, means any connection or coupling, either direct or indirect, between two or more elements; the coupling of connection between the elements can be physical, logical, or a combination thereof. Additionally, the words “herein,” “above,” “below,” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application. Where the context permits, words in the above Detailed Description using the singular or plural number can also include the plural or singular number respectively. The word “or,” in reference to a set of two or more items, covers all of the following interpretations of the word: any of the items in the list, all of the items in the list, and any combination of the items in the list.
The above detailed description of embodiments of the system is not intended to be exhaustive or to limit the system to the precise form disclosed above. While specific embodiments of, and examples for, the system are described above for illustrative purposes, various equivalent modifications are possible within the scope of the system. For example, some network elements are described herein as performing certain functions. Those functions could be performed by other elements in the same or differing networks, which could reduce the number of network elements. Alternatively or additionally, network elements performing those functions could be replaced by two or more elements to perform portions of those functions. In addition, while processes, message/data flows, or blocks are presented in a given order, alternative embodiments may perform routines having steps, or employ systems having blocks, in a different order, and some processes or blocks may be deleted, moved, added, subdivided, combined, and/or modified to provide alternative or subcombinations. Each of these processes, message/data flows, or blocks may be implemented in a variety of different ways. Also, while processes or blocks are at times shown as being performed in series, these processes or blocks may instead be performed in parallel, or may be performed at different times. Further any specific numbers noted herein are only examples: alternative implementations may employ differing values or ranges. One will also appreciate that the actual implementation of a database can take a variety of forms, and the term “database” is used herein in the generic sense to refer to any data structure that allows data to be stored and accessed, such as tables, linked lists, arrays, etc.
The teachings of the methods and system provided herein can be applied to other systems, not necessarily the system described above. The elements and acts of the various embodiments described above can be combined to provide further embodiments. Aspects of the disclosure can be modified, if necessary, to employ the systems, functions, and concepts of the various references described above to provide yet further embodiments of the disclosure.
These and other changes can be made to the invention in light of the above Detailed Description. While the above description describes certain embodiments of the disclosure, and describes the best mode contemplated, no matter how detailed the above appears in text, the invention can be practiced in many ways. Details of the system may vary considerably in its implementation details, while still being encompassed by the technology disclosed herein. As noted above, particular terminology used when describing certain features or aspects of the disclosed techniques should not be taken to imply that the terminology is being redefined herein to be restricted to any specific characteristics, features, or aspects of the disclosed techniques with which that terminology is associated. In general, the terms used in the following claims should not be construed to limit the invention to the specific embodiments disclosed in the specification, unless the above Detailed Description section explicitly defines such terms. Accordingly, the actual scope of the invention encompasses not only the disclosed embodiments, but also all equivalent ways of practicing or implementing the invention under the claims.
While certain aspects of the disclosed techniques are presented below in certain claim forms, the inventors contemplate the various aspects of the techniques in any number of claim forms. For example, while only one aspect of the invention is recited as embodied in a computer-readable medium, other aspects can likewise be embodied in a computer-readable medium. Accordingly, the inventors reserve the right to add additional claims after filing the application to pursue such additional claim forms for other aspects of the disclosed techniques.
This application is a continuation of PCT International Application No. PCT/US2020/066933, titled “Digital Interface for Frequency Domain Data Transfer Between Baseband and Radiofrequency Modules,” filed Dec. 23, 2020, which claims priority to U.S. Provisional Application No. 62/982,627, titled “Transfer Frequency Domain Data to Reduce BB-RF Digital Interface Throughput,” filed on Feb. 27, 2020. The aforementioned applications are incorporated herein by reference in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62982627 | Feb 2020 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US2020/066933 | Dec 2020 | US |
| Child | 17819748 | US |
