{"title": "Senior Wireless System Engineer \u2013 DSP for Power Amplifier Linearization", "summary": "At Apple, we work every single day to craft products that enrich people\u2019s 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\u2019s customers every single day.\n\nFor wireless system, power amplifiers (PA) in the transmitter are the main source of power consumption. To improve efficiency, PA must be designed beyond the classic class-AB, together with enhancement using envelope tracing, or envelope elimination and restoration (EER, or polar transmitter). Those designs come with impairments or nonlinear distortion that need to be clean up using digital signal processing techniques. RF/analog architectures, with the help of DSP, their optimizations and calibrations are the critical technique to achieve such high performing systems. \n\nIn this technical role, you will be at the center of a silicon design group responsible for using digital algorithm or method to improve the PA efficiency, reducing power consumption, but with acceptable linearity for high data rate applications. You will mainly work on architecting various calibration and correction methods for implementation in hardware/firmware and validation of overall performance enhancement through lab measurement. You will interact with RF/analog designers, software or firmware engineers, digital designers, product engineers and architects to define and specify parts in the wireless systems.", "description": "In this role, core responsibilities include, but are not limited to, the following:\n\u2022Design and simulate state-of-the-art wireless transmitter for very high data rate applications.\n\u2022Investigate innovative PA architectures, calibration algorithms, processing structures for performance enhancement.\n\u2022Architect HW/FW/SW partitioning of various calibrations for area and time efficiency.\n\u2022Implement system models of the analog front-end design, impairments and come up with right controls and calibrations in C and MATLAB for optimal system performances.\n\u2022Work with digital designers to realize these methods with power and area efficient digital implementations.\n\u2022Work with firmware designers to realize these methods with high efficiency software implementation, and possibility hardware acceleration.\n\u2022Bring up, test and characterize real silicon with relevant implementation in lab.", "key_qualifications": "Extensive experience in designing relevant signal processing for wireless communications systems.\nProven track record of optimization algorithm and its applications to RF calibration\nGood understanding of the methods to estimate various RF impairments via direct equipment measurement or self-testing via loopback.\nExperiences in digital predistortion, crest-factor reduction, nonlinear crosstalk/interference cancellation, and real-chip bring-up in lab\nMATLAB or Python or C/C++ for algorithm development, modeling and simulation.\nHands on experience on lab testing and characterization (such as spectrum analyzer, signal generator, signal analyzer, power meter, etc.).\nSome 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.\nPreferred to understand communication theory & signal processing related algorithms design (such as timing recovery, signal estimation and detection, automatic gain control, channel estimation, equalization, coding theory, etc.)\nPreferred to have some knowledge in existing wireless communication protocols: 5G-NR/LTE/WCDMA/GSM, 802.11 WiFi, and/or Bluetooth/BLE\nCourse works and experience in circuit design \u2013 a plus", "preferred_qualifications": "", "education_experience": "BS and 10+ years of relevant experience required. MSEE/PhD preferred", "additional_requirements": "", "pay_benefits": "At Apple, base pay is one part of our total compensation package and is determined within a range. This provides the opportunity to progress as you grow and develop within a role. The base pay range for this role is between $166,600 and $296,300, and your base pay will depend on your skills, qualifications, experience, and location.\n\nApple employees also have the opportunity to become an Apple shareholder through participation in Apple\u2019s discretionary employee stock programs. Apple employees are eligible for discretionary restricted stock unit awards, and can purchase Apple stock at a discount if voluntarily participating in Apple\u2019s Employee Stock Purchase Plan. You\u2019ll also receive benefits including: Comprehensive medical and dental coverage, retirement benefits, a range of discounted products and free services, and for formal education related to advancing your career at Apple, reimbursement for certain educational expenses \u2014 including tuition. Additionally, this role might be eligible for discretionary bonuses or commission payments as well as relocation. Learn more about Apple Benefits.\n\nNote: Apple benefit, compensation and employee stock programs are subject to eligibility requirements and other terms of the applicable plan or program.", "company": "apple"}