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Hardware Choices For SDR

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  1. Hardware Choices For SDR Created & Presented by : Ali Masoudi

  2. Content • Important Choices (Platforms) • ASICs • Embedded Processors • DSPs • FPGAs • Picochip • Conclusion SDR Course Project

  3. ASICs • An application-specific integrated circuit(ASIC) is an integrated circuit (IC) customised for a particular use, rather than intended for general-purpose use. • Modern ASICs often include entire 32-bit processors, memory blocks including ROM, RAM, EEPROM, Flash and other large building blocks. Such an ASIC is often termed a SoC (System-on-a-chip). • ASICs perform signal downconversion, digital filtration, and perform at higher rates of speed than FPGAs. SDR Course Project

  4. ASICs (design) • Gate array design • Gate Array design is a manufacturing method in which the diffused layers, i.e. transistors and other active devices, are predefined and wafers containing such devices are held in stock prior to metallization • Standard cell design • Every ASIC manufacturer could create functional blocks with known electrical characteristics, such as propagation delay, capacitance and inductance, which could also be represented in third party tools. • Full-custom design • Full-Custom ASIC Design defines all the photo lithographic layers of the device. SDR Course Project

  5. ASICs (design) • The significant difference is that Standard Cell design uses the manufacturer's cell libraries that have been used in potentially hundreds of other design implementations and therefore are at much lower risk than full custom design. Standard Cells produce a design density that is cost effective, and they can also integrate IP cores and SRAM effectively, unlike Gate-Arrays. • IP Core = Intellectual Property Core • IP core is a reusable unit of logic, cell, or chip layout design and is also the intellectual property of one party. SDR Course Project

  6. ASICs (design) • The benefits of Full-Custom Design usually include : • Reduced area (and therefore recurring component cost), performance improvements and also the ability to integrate (include) analog components and other pre-designed (and thus fully verified) components such as microprocessor cores that form a System-On-Chip. • The disadvantages of Full-Custom can include : • Increased manufacturing and design time, increased non-recurring engineering costs, more complexity in the Computer Aided Design (CAD) system and a much higher skill requirement on the part of the design team. SDR Course Project

  7. Content • Important Choices (Platforms) • ASICs • Embedded Processors • DSPs • FPGAs • Picochip • Conclusion SDR Course Project

  8. Embedded Processors • An Embedded Processors is simply a uProcessors that has been “Embedded” into a device • It is software programmable but interacts with different pieces of hardware - how ? • Performs both control and computation. more performance than a uController but not as much performance as a general purpose processor. • Where are they used: • Cars, Phones, Media Devices, Wireless, Printers, … SDR Course Project

  9. Embedded Processors What is it really ? • Typically an Embedded Processor is a single-issue in-order RISC processor with a little cache. • It can then sold as a piece of silicon, custom layout, netlist, or architectural description • They are designed to be small, low power, and most importantly correct. • Often due to the real-time constraints of an application area they are designed to have a small deterministic worst case time per instruction. SDR Course Project

  10. Embedded Processors Why use an Embedded Processor? • The main reason is simple: Cost • Embedded processors are small so they don’t take up much die area and thus they are cheap to fab. • Embedded processors are verified so I won’t spend a bunch of engineering man hours tracking down hardware bugs so I can tape out my chip. • Embedded processors run software • the key part of that is the SOFT (deal with changing specs) SDR Course Project

  11. Embedded Processors • Cost, Power, and Size are important for embedded applications • Embedded processors occupy more than 95% of the entire processor market • A large number of electronic products require high-end 32/64-bits embedded processors • Today, the ARM family accounts for approximately 75% of all embedded 32-bit RISC CPUs, making it one of the most prolific 32-bit architectures in the world. SDR Course Project

  12. ARM • The ARM architecture (previously, the Advanced RISC Machine, and prior to that Acorn RISC Machine) is a 32-bit RISC processor architecture developed by ARM Limited that is widely used in a number of embedded designs. Because of their power saving features, ARM CPUs are dominant in the mobile electronics market, where low power consumption is a critical design goal. • ARM's 2006 annual report and accounts state that royalties totaling $164.1 million were the result of licensees shipping 2.45 billion units. This is equivalent to 6.7 cents per unit shipped • In the same year ARM's licensing revenues for processor cores were $119.5 million, in a year when 65 processor licenses were signed, an average of $1.84 million per license. SDR Course Project

  13. Content • Important Choices (Platforms) • ASICs • Embedded Processors • DSPs • FPGAs • Picochip • Conclusion SDR Course Project

  14. DSPs • A digital signal processor(DSP) is a specialized microprocessor designed specifically for digital signal processing, generally in real-time computing. • Characteristics • Designed for real-time processing • Optimum performance with streaming data • Separate program and data memories • Special Instructions for SIMD (Single Instruction, Multiple Data) operations • No hardware support for multitasking • The ability to act as a direct memory access device if in a host environment • Processes digital signals SDR Course Project

  15. DSPs • The heart of the software defined radios rests in the digital signal processing units. • Digital signal processing can be done on general-purpose microprocessors. However, a DSP contains architectural optimizations to speed up processing. These optimizations are also important to lower costs, heat-emission and power-consumption. • DSPs often use special memory architectures that are able to fetch multiple data and/or instructions at the same time. SDR Course Project

  16. DSPs • Most DSPs use fixed-point arithmetic, because in real world signal processing, the additional range provided by floating point is not needed, and there is a large speed benefit and cost benefit due to reduced hardware complexity. Floating point DSPs may be invaluable in applications where a wide dynamic range is required but it is generally easier to implement algorithms in floating point. • Embedded general-purpose RISC processors are becoming increasingly DSP in functionality. For example, ARM. • Generally, DSPs are dedicated integrated circuits, however DSP functionality can also be realized using FPGAs. SDR Course Project

  17. Content • Important Choices (Platforms) • ASICs • Embedded Processors • DSPs • FPGAs • Picochip • Conclusion SDR Course Project

  18. FPGAs • FPGA = Field Programmable Gate Array • Basic Section of FPD: • Logical Block • Routing (Switch Matrix) • Input Output Block • More Advanced FPD Contains: • On-chip Memory • Embedded Processor • Clock Management • High-Speed Transceiver SDR Course Project

  19. FPGA Structures • Basic Lookup Table (LUT) SDR Course Project

  20. FPGA Structures • Synchronous Look-UP SDR Course Project

  21. FPGA Structures • Configurable Logic Block (CLB) • Two identical slices in each CLB • Two LUT in each slice • RAM Blocks • Xilinx core generator • Synplify ( Best Synthesizer in the world ) • CLK - Delay Locked Loop (DLL) SDR Course Project

  22. CLB Slice SDR Course Project

  23. CLK - DLL • In dealing with a DDR-RAM , CLK-DLL can multiply frequency of CLK by factor 2 , by generating the same signal with 180 degree shift in phase . SDR Course Project

  24. FPGAs • Spartan-II FPGA Family SDR Course Project

  25. FPGA Advantages • Designing with FPGA: Faster, Cheaper • Ideal for customized designs • Product differentiation in a fast-changing market • Offer the advantages of high integration • High complexity, density, reliability • Low cost, power consumption, small physical size • Avoid the problems of ASICs • high NRE cost, long delay in design and testing • increasingly demanding electrical issues SDR Course Project

  26. FPGA Advantages (cont.) • Very fast custom logic • massively parallel operation • Faster than microcontrollers and microprocessors • much faster than DSP engines • More flexible than dedicated chipsets • allows unlimited product differentiation • More affordable and less risky than ASICs • no NRE, minimum order size, or inventory risk • Reprogrammable at any time • in design, in manufacturing, after installation SDR Course Project

  27. FPGA Advantages (cont.) • Very fast custom logic • massively parallel operation • Faster than microcontrollers and microprocessors • much faster than DSP engines • More flexible than dedicated chipsets • allows unlimited product differentiation • More affordable and less risky than ASICs • no NRE, minimum order size, or inventory risk • Reprogrammable at any time • in design, in manufacturing, after installation SDR Course Project

  28. User Expectations • Logic capacity at reasonable cost • 100,000 to a several million gates • On-chip fast RAM • Clock speed • 150 MHz and above, global clocks, clock management • Versatile I/O • To accommodate a variety of standards • Design effort and time • synthesis, fast compile times, tested and proven cores • Power consumption • must stay within reasonable limits SDR Course Project

  29. Content • Important Choices (Platforms) • ASICs • Embedded Processors • DSPs • FPGAs • Picochip • Conclusion SDR Course Project

  30. Picochip • The picoArray™ is a multi-processor IC which integrates hundreds of processing elements into a single array. • The individual elements have been optimized for signal processing and wireless algorithm computation and control. • The result is a general purpose wireless communications processor, capable of executing all contemporary wireless standards, which combines the computational density of a dedicated ASIC with the programmability of a traditional high-end Digital Signal Processor (DSP). SDR Course Project

  31. Picochip • Targeted at wireless communications applications • software design simpler than hardware • software defined gives flexibility • scalable solution • Why highly parallel hardware? • wireless systems have great deal of parallelism • Replacement for DSP, ASIC, FPGA combinations • single architecture • single development environment SDR Course Project

  32. I P P P I P + P P P P P P P P P P P P P P P + P P P + P P P P P P I I P P P P P P P P I P I Picochip - Architecture Switch Matrix Example signal flows Processor Inter-picoArray Interface or Asynchronous Data Interface SDR Course Project

  33. configuration bus Config Instruction Memory Data Memory Processor Ports 32-bit picoBus 32-bit picoBus Picochip - Array Elements (AE) • 16-bit processor • 64-bit LIW targeting 3 execution units • 160MHz clock • Harvard architecture • Processor and ports work independently SDR Course Project

  34. Picochip - Picobus SDR Course Project

  35. Picochip • picoArray concept gives scalable, software defined systems • Rapid development due to • deterministic communications • single programming environment • Integrated tool set • Design Browser provides design visualisation • Probes provide non-invasive debugging and monitoring • We want to have a SDR in wireless communications. The best choice is Picochip. SDR Course Project

  36. Host Processor Interface Picochip - PC102 • Current instantiation of the picoArray • Peak performance • 197 GIPS • 38.6 GMACs • 3.3Tbps communications bandwidth • 308 processors • 14 co-processor accelerators for FEC, correlators External Memory Interface SDR Course Project

  37. Content • Important Choices (Platforms) • ASICs • Embedded Processors • DSPs • FPGAs • Picochip • Conclusion SDR Course Project

  38. Conclusion • It is apparent that ASICs, DSPs, FPGAs are not capable of satisfying the power & efficiency requirements of mobile devices. • The typical result emerging is thus a hybrid design that is a combination of ASICs, DSPs, FPGAs. • FPGAs provide a strong platform for specialized digital signal processing tasks for SDRs. They have been used with success in wireless research environments • For example, describes FPGA-based FIR filters, FPGA-based CIC filters, extended precision arithmetic, and a CORDIC carrier recovery loop for a runtime reconfigurable digital receiver. SDR Course Project

  39. The Benefits of FPGA Coprocessing • High-performance DSP platforms, traditionally based on general-purpose DSP processors running algorithms have been migrating towards the use of an FPGA pre-processor or coprocessor. • Doing so can provide significant performance, power, and cost advantages. • Even with these considerable advantages, design teams accustomed to working on processor-based systems may avoid using FPGAs because they lack the hardware skills necessary to use one as a coprocessor. SDR Course Project

  40. Conclusion SDR Course Project You can realize significant improvements in the performance of a DSP system by taking advantage of the flexibility of the FPGA. Common examples include (but are not limited to) FIR filtering, FFTs, digital down conversion, and forward error correction (FEC) blocks.

  41. Conclusion SDR Course Project

  42. Thanks Questions ?