22. VLSI in Communications

Transcription

1 22. VLSI in Communications State-of-the-art RF Design, Communications and DSP Algorithms Design VLSI Design Isolated goals results in: - higher implementation costs - long transition time between system level design and final implementation Performance Improvement Power-Area-Speed optimization Flexibility Risk minimization 2

2 RF Design, Communications and DSP Algorithms Design Trends VLSI Design Trade-off during the development (Interdisciplinary Issue) Performance vs. VLSI-relevant design aspects Algorithmic transformation techniques Architectural transformation techniques Low-power design of baseband processing Low-power RF design Analog-digital co-design methodologies High-speed low power AD/DA converters 3 Challenge Towards complex on-chip wireless system design The increasing communication and multimedia processing can cope with the high integration density of microelectronic circuits 1. Key ingredients - maximize digital components - minimize analog, passive elements (i.e. Simplification of design requirements of analog components, moving to digital processing as early as possible) - Low power design techniques 2. Analog portions continue to dominate power consumption Example: DS-CDMA RX (32 MHz chip) realized in 2 chips using 0.8 µ CMOS Analog front-end (amp, sampling, demod, AD/DA) Digital baseband signal processing 107 mw 27 mw 4

3 AWGN 6Mbps 9Mbps 12Mbps 18Mbps 27Mbps 36Mbps 54Mbps C / N [db] System Description Modeling Language e.g. Matlab, C, C++, SDL,... Graphical Environment Design Flow: Overview System Design Simulation and Analysis Frequency Spectrum Eye Pattern Digital Digital Baseband Processing Code Generation SOFTWARE Hardware Description (VHDL, Verilog) Compiler Optimization HARDWARE Placement & Routing Synthesis (RTL, High Level) Dataflow-oriented (e.g. Signal Processing) Tools:Cossap, Simulink, SPW,... Controlflow -oriented (e.g. Protocols) Tools: Statemate Bit Error rate Bit Error Rate State Diagramm Analog Analog & RF Design Description (VHDL AMS, Spice,...) Simulation (SPECTRE,...) Layout Generation Goal ADC DAC Analog RF Data Path Control Logic RAM ROM Cores (DSP, RISC) 5 Overview: Generic Transceiver Architecture ADC I Duplexer LNA Mixer VCO IF Mixer Demod. IF PLL ADC DAC Q I Digital Baseband Processing - Diversity Reception - Equalization (RLS, Viterbi) - Channel Coding/Decoding - Voice Coding/Decoding - Interleaving/Deinterleaving - Encryption/Decryption Power Amplifier Modulator Transmit PLL VCO ANALOG DAC Q DIGITAL 6

4 IC Technologies 7 IC Technologies for Communication Applications Which technology is the most suitable for future communication systems? Criteria: Support of high frequencies Analog/digital integration capabilties High integration density Low RF and IF noise Low power consumption High gain Portfolio of technologies: Silicon CMOS, SOI, BiCMOS and BJT Silicon-Germanium(SiGe) HEMT and HBT Gallium-Arsenide (GaAs) MESFET, HEMT and HBT HBT: Hetero Bipolar Transistor; HEMT: High Electronic MobilityTransistor; SOI: Silicon-On-Insulator; BJT: Bipolar Junction Transistor 8

5 IC Technologies (cont d) SILICON CMOS BiCMOS BJT Features up to 30 GHz up to 40 GHz (0.15 µm) up to 30 GHz up to 40 GHz up to 80 GHz up to 75 GHz Application Digital baseband Trends:RF, IF and analog baseband Intermediate frequency (IF) modules IF and RF modules (1999) CMOS is currently the best IC technology for single chip solutions (analog + digital) for communication applications CMOS technologies Advantages: Mature technology, high integration density, cost-effective Drawbacks: Bad noise figure, bad linearity, substrate parasitics 9 IC Technologies (cont d) CMOS RF Design: Example RF-frontend components (LNA, mixer and VCO) developed using standard CMOS processes Realization with separated dies Source: Fraunhofer-Gesellschaft LNA = Low Noise Amplifier VCO = Voltage-Controlled Oscillator 10

6 IC Technologies (cont d) SILICON GERMANIUM (SiGe) HBT HEMT Features up to 130 GHz up to 160 GHz up to 30 GHz up to 120 GHz Application - LNA, PA, mixers, VCO, PLL - High speed DA and AD converters Advantages: - Easy integration into standard silicon processes (BJT, BiCMOS, CMOS) - Improved frequency response - Better cost/performance trade-off Disadvantage: - Technology process not mature 11 IC Technologies (cont d) HBT SiGe RF Design: Example (Source: Temic Semiconductors) DECT LNA & PA Noise figure: 1.6 db Gain: GHz Amplification: 27 dbm (Source: Temic Semiconductors) GSM PA Amplification: dbm Vop = V 12

7 IC Technologies (cont d) GALLIUM ARSENIDE (GaAs) MESFET HEMT HBT Features up to 100 GHz up to 115 GHz up to 180 GHz up to 220 GHz up to 90 GHz up to 110 GHz Application - Amplifiers (PA, LNA), mixers - Ultrafast DA and AD converters (Gigahertz sampling rates) Advantages: - Good analog capabilities, high linearity, high-speed operations Disadvantages: - Expensive process, technology process not mature (in comparison to other processes such as CMOS) 13