From Bits to Antenna to RF: Wireless System Design with MATLAB

From Bits to Antenna to RF: Wireless System Design with MATLAB Houman Zarrinkoub, PhD. Signal Processing & Communications MathWorks houmanz@mathworks.com 2014 The MathWorks, Inc. 1

Agenda Landscape of wireless design Antenna-to-Bit simulation Case study: 802.11n/ac/ad Systems Smart RF design Case study: ADI Agile Transceiver Modeling LTE and LTE-Advanced Case study: MU-MIMO Summary 2

Mobile Communications: LTE, 5G and Beyond 5G standardization 100-1000 times faster speeds Reliable service everywhere Greater complexity New architectures New frequency bands (mmwave) More antennas (massive MIMO) Advanced RF and DSP co-design 3

Connected Smart Devices, Internet of Things Internet of Things Embedded sensors Digital health Industrial instruments Pervasive computing Connected wirelessly to internet Low power Generate lots of data 4

Wireless System Design: MATLAB and Simulink Who are our users? R&D algorithm designer Digital baseband engineer RF system engineer Test or validation engineer Multi-domain system Single domain system Wireless System Design What do they need? Algorithm End-to-end simulation Simulate & Analyze Prototype & Test Implement Design verification Real-world over-the-air testing 5

1 2 3 Antenna to Bits simulation Smart RF design LTE & LTE-Advanced 6

Antenna-to-Bits Simulation MATLAB & Simulink Simulate a complete wireless link Design modern wireless systems with components such as MIMO, OFDM, and adaptive beam-forming Analyze signals and make measurements such as EVM, ACLR, BLER, Throughput Generate waveforms and create verification references for downstream implementation New Antenna Toolbox 1.0 released in R2015a 7

Demo: 802.11n/ac/ad modeling a MIMO-OFDM system Step-by-step MATLAB demo OFDM as the air interface technology of 802.11n Beamforming as a MIMO technique Easy-to-follow end-to-end simulation Graphical test bench Adjustment of channel characteristics on the fly 8

How does a MIMO-OFDM System work? Transmitter Input bits Channel coding Modulation MIMO.... Large-scale fading (path-loss ) Channel Small-scale fading (Multipath, Doppler effects) Interference Output bits Receiver Channel decoding Demodulation MIMO Receiver (Equalizer) Channel estimation OFDM receiver Noise OFDM receiver 9

Baseband demo workflow 10

Version 1: Baseline - Modulation and Coding Start with a SISO transceiver with modulation, coding, scrambling Channel modeling (Interferer + path loss) No multipath fading yet Isotropic (non-directional) antennas (1x1) θθ II Interference Source (I) Signal Source (S) dd SS θθ SS dd II 11

MATLAB tools for modeling of adaptive modulation and coding Use algorithms in Communications System Toolbox Quickly build and run fast & reliable simulations Simulate dynamic changes of systems (such as modulation scheme) Perform measurements and examine performance metrics during simulation 12

Version 2: Baseline + OFDM Introduce OFDM transmission Transceiver with modulation, coding, scrambling & OFDM transmitter & receiver Channel (Interferer + path loss) modeling No multipath fading yet Interference Source (I) Signal Source (S) dd II dd SS 13

MATLAB tools for modeling OFDM multicarrier transmission systems OFDM modulator and demodulator from Communications System Toolbox Gold or PN Sequence generators to generate pilots (reference signals) System objects make exploring with system parameters easier Explore a wide range of center frequencies and bandwidths 14

Version 3: Baseline + OFDM + Transmit-side beamforming Introduce Receive-side beamforming Transceiver with modulation, coding, scrambling, OFDM transmitter & SIMO receiver Channel with Interferer + path loss + fading Receiver has multiple Antennas (1 to 8) Signal Source (S) Interference Source (I) 15

MATLAB tools for modeling multi-antenna systems and beamforming Antenna arrays and beamformers from Phased-Array System Toolbox 2-D and 3-D spatial array responses and directional gains Implement null-steering and interference cancelation algorithms with a few lines of MATLAB code Easily quantify interference mitigation gains provided by beam-forming 16

Version 4: Baseline + OFDM + Transmit-side beamforming + Multipath fading Introduce Transmit-side beamforming with Multipath fading Transceiver with modulation, coding, scrambling, MIMO-OFDM transmitter & receiver Channel with Interferer + path loss + fading Transmitter has multiple Antennas (1 to 8) Signal Source (S) Interference Source (I) 17

MATLAB tools for modeling fading channels and channel estimation-equalization MIMO fading channels from Communications System Toolbox Channel estimation and equalization with received values of time-frequency grid Combine OFDM and MIMO to approach a prototype of 802.11n/ac Experiment with ideal and pilot-based channel estimation algorithms 18

What We Learned in This Demo Easily setup MIMO-OFDM system components Modulation, coding, OFDM MIMO fading channels Beamforming, beam steering & interference cancelation Dynamic & interactive MATLAB test benches On-the-fly tunable parameters Spectral analysis Visualizations and measurements Qualitative and quantitative metrics Live feeds of telemetry data as transmitted bit stream 19

Antenna Toolbox Easy design Library of 22 parameterized antenna elements Functionality for the design of linear and rectangular antenna arrays No need for full CAD design Rapid simulation setup Method of Moments field solver for port, field, and surface analysis No need to be an EM expert Seamless integration Model the antenna together with signal processing algorithms Rapid iteration of different antenna scenarios for radar and communication systems design 20

Antenna Toolbox Demo Build your first antenna array >> a = lineararray >> a.element = p; >> a.elementspacing = 0.1; >> a.numelements = 4; >> layout(a); >> pattern(a, 1.66e9); 21

Integration Demo: Phased Array System Toolbox atx_array_modeling_with_embedded_element_pattern... % Import antenna element in Phased Array myura1 = phased.ura; Phased Array myura1.element = mydipole; Antenna element... % Import the embedded element pattern EmbAnt = Phased.CustomAntennaElement(... 'FrequencyVector',freqVector,... 'AzimuthAngles',az,... 'ElevationAngles',el,... 'RadiationPattern',embpattern); myura2 = phased.ura; myura2.element = EmbAnt;... Pattern of the embedded element computed with Antenna Toolbox 22

Learn more about measurement, analysis, visualization Constellation Scope Visualizes the effects of channel degradations on modulated symbols Shows rotations and attenuations caused by various fading mechanism Measurements included: EVM MER Spectrum Analyzer Visualizes flat or frequency-selective nature of channel Measurements included: Complimentary Cumulative Distribution Function (CCDF) measurement and visualization Adjacent Channel Power Ratio (ACPR) measurements Harmonic & Intermodulation distortions 23

Learn more about Speeding up simulations Use Best Practices in Programming Vectorization Pre-allocation Parallel Computing High level parallel constructs (e.g. parfor) Utilize cluster, clouds, and grids MATLAB to C GPUs Webinar: Accelerating Communications System Simulations in MATLAB 24

Summary We have modern algorithms (OFDM and MIMO) & analysis tools and even modern standard-based products (LTE) for modern systems We have incorporated features and tools like C code generation, parallel computing etc. into our tool that substantially accelerate simulation We now have very high end communications measurements and analysis tools like Spectrum Analyzers, etc. They work directly in MATLAB and come at the low toolbox price 25

1 2 3 Antenna to Bits simulation Smart RF design LTE & LTE-Advanced 26

Smart RF Design Fast behavioral RF modeling & simulation Model and simulate RF transceiver together with baseband algorithms Develop calibration and control algorithms such as DPD or AGC to mitigate impairments and interferers Add measured RF component characteristics Use circuit envelope techniques to accelerate simulation of RF transceivers MATLAB & Simulink Analog Devices AD9361 RF Agile Transceiver 27

Example: Simulation of Analog Devices RF Transceivers with MATLAB and SimRF AGC RSSI 28

RF Receiver AGC Manual and slow attack mode RSSI CW test signal LTE-like or custom test signal Tunable RF receiver Analog continuous-time programmable filters Third order Delta-Sigma ADC Multi-rate finite-precision programmable decimation filters 29

Simulation Results: MGC, 2 Tones In-band noise Images DC Offset IP2 Fundamental IP3 30

Which Tools? MATLAB, Simulink and 31

Learn More About: RF Modeling SimRF: fast simulation of RF front-ends Design the architecture and specs of the RF front-end Integrate RF with adaptive algorithms such as DPD, AGC Test and debug the implementation before going in the lab Provide a model to your colleagues and customers Webinar: Design and Verify RF Transceivers for Wireless Communication Systems 32

Trade Off Simulation Speed and Modeling Fidelity How do your signals look like? Simulation speed Equivalent Baseband Spectrum Signal bandwidth Carrier Circuit Envelope Spectrum freq DC Carrier 1 Carrier 2 freq True Pass-Band Spectrum Modeling fidelity freq 33

Summary Executable specifications of real-life communication systems across multiple disciplines Develop smarter algorithms faster Improve the communication between different teams Understand, debug, test your system before going in the lab Provide (IP protected) models to the end users 34

1 2 3 Antenna to Bits simulation Smart RF design LTE & LTE-Advanced 35

LTE & LTE-Advanced Design, simulate, and test LTE and LTE-Advanced systems Specify your LTE and LTE-A PHY systems covering all transmission modes, channels, and signals Combine your LTE baseband models with RF modeling for a combined digital-rf design New features in R2015a LTE Rel. 11 support UMTS/HSPA+ Waveform Generation Coordinated Multipoint (CoMP) MATLAB & Simulink Qualifying question Are you working on LTE Physical layer? 36

What s the LTE System Toolbox? Release 8,9, 10 &11 (LTE-A) Scope TDD/FDD, Uplink/Downlink Transmitter/Receiver ~200 functions for physical layer (PHY) modeling Link-level simulation Conformance Tests 37

Signal Generation and Analysis Reference Measurement Channels TS 36.101 Standard-compliant signal available in the MATLAB workspace >> ltermcdltool 38

Typical Use Cases Golden reference to verify in-house PHY models Complete end-to-end link-level simulation Signal generation and analysis Transmitter Test Waveform Generation RF Signal Generator Signal information recovery 39

Demo: Equalizing the Downlink Grid Transmitter Channel Receiver Test Waveform Generation Fading Channel Synchronisation & OFDM Demodulation Channel Estimation & Equalisation 40

Summary Comprehensive Comprehensive set of PHY models Numerous preset, extensible examples Open environment MATLAB-based Link to test and measurement instruments Standard-compliance Ability to generate and transmit signals using hardware signal generators Trusted by numerous customers 41