Sr. Wireless System Engineer – Digital Enhancements for Radio systems
Santa Clara Valley (Cupertino), California, United States
At Apple, we work every single day to craft products that enrich people’s lives. Do you love working on challenges that no one has solved yet? Do you like changing the game? We have an opportunity for a forward-thinking and unusually hardworking Wireless System Engineer. As a member of our dynamic group, you will have the rare and extraordinary opportunity to craft upcoming products that will delight and encourage millions of Apple’s customers every single day. In this technical role, you will be at the center of a silicon design group responsible for using digital algorithm or method to improve the RF/analog performances of state-of-the-art wireless communication SoC products for newly emerging demanding applications for very high data rate, high efficiency, low latency, fast switching and accurate ranging detections, where achieving low EVM, high linearity, low power consumption, fast settling etc. are becoming critical. Using digital algorithm, coming up with novel RF/analog architectures, their optimizations and calibrations are one of critical techniques for achieving such high performing systems. You will be involved in developing systems model of RF/analog designs and evaluating associated impairments, and investigating innovative designs for performance enhancements for novel digitally aided radio architecture, enhancements, calibration for radio circuits characteristics matching, signal quality controls such as crest-factor-reduction (CFR), digital predistortion for nonlinearities due to IQ imbalance or power-amplifier, beamforming for nonlinearities or interference nulling, digital cancellations of interference sources, etc. You will also work on architecting various calibration and correction methods for implementation in hardware/firmware, and validation of overall performance enhancement through lab measurement. Above all, you will interact with RF/analog designers, software or firmware engineers, digital designers, product engineers and architects to define and specify parts of the whole wireless systems. If necessary, you will get to work with digital designers to realize these methods with power and area efficient digital implementations, and to work with firmware designers to realize these methods with high efficiency software implementation, and possibly with hardware acceleration. And to bring up, test, characterize, and optimize real silicon in lab to the production qualities.
- - At least 7+ year experience in designing relevant signal processing for the wireless communications systems.
- - Deep understanding of RF and analog components/modules composited of wireless communication systems, the possible impairments from those components, their impact to MIMO OFDM signals, and the corresponding calibration and impairment reduction methods/algorithms is essential.
- - Proven track record of designing calibration algorithms for Tx Power, RSSI, digital predistortion, PAPR reduction algorithms, LO leakage or IQ mismatch.
- - Understand the methods to estimate various RF impairments via direct equipment measurement or self-testing via loopback.
- - Experience with MATLAB or Python and/or C/C++ for algorithm development, modeling, and simulation.
- - Hands on experience on lab testing & characterization will be essential (such as spectrum analyzer, signal generator, power meter, etc.).
- - Experience on bring up real silicon in lab is a plus.
- - Preferred to have basic understanding of communication theory & signal processing related algorithms design (such as timing recovery, signal estimation and detection, automatic gain control, channel estimation, equalization, coding theory, etc.)
- - Preferred to have some knowledge in existing wireless communication protocols: 5G-NR/LTE/WCDMA/GSM, 802.11a/b/g/n/ac/ax, 802.11ad/ay, and/or Bluetooth/BLE
- Design and simulate state-of-the-art wireless communication system for very high data rate applications. - Investigate innovative algorithms, processing structures for digitally aided radio/analog system architectures for enhanced performances. - Investigate innovative algorithms to alleviate various RF and analog impairments, and design calibration and correction methods to allow the improved performance. - Architect HW/FW/SW partitioning of various calibrations for area and time efficiency. - Implement system models of the analog front-end design, impairments and come up with right controls and calibrations in C and MATLAB for the end-to-end optimal system performances. - Work with digital designers to realize these methods with power and area efficient digital implementations. - Work with firmware designers to realize these methods with high efficiency software implementation, and possibility hardware acceleration. - Bring up, test and characterize real silicon with relevant implementation in lab.
Education & Experience
MS with 11+ years’ experience or Ph.D. with 7+ years’ experience.