DSP Wireless Systems Engineer

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 exceptional DSP Wireless System Engineer. As a member of our multifaceted 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. For 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 (DSP) techniques. The optimization and calibration of those DSP techniques are the critical to achieve high performing systems. 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 PA efficiency, reducing power consumption, but with acceptable linearity for high data rate applications.

Description

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 collaborate RF/analog designers, software or firmware engineers, digital designers, product engineers and architects to define and specify parts in the wireless systems. You will also get to work with digital designers and firmware designers to realize these methods with power and area efficient digital implementations with high efficiency software implementations, and possibly with hardware acceleration. You will also get to participate in bring up, test, characterize, and optimize real silicon in lab to the production efforts.

Minimum Qualifications

BSEE and a minimum of 10 years relevant industry experience.
Experience in designing relevant signal processing for wireless communications systems.
Understand methods to estimate various RF impairments via direct equipment measurement or self-testing via loopback.
Experience with MATLAB, Python and/or C/C++ for algorithm development, modeling, and simulation.
Hands-on experience on lab testing & characterization will be crucial such as spectrum analyzer, signal generator, signal analyzer, power meter.
Basic understanding of RF and analog components/modules composited of wireless communication systems, possible impairments from the components, impact to OFDM signals, corresponding calibration and impairment reduction.

Preferred Qualifications

MSEE/PhD with proven experience.
Proven track record of optimization algorithm, and its applications to RF calibration.
Previous experiences on digital pre-distortion, crest-factor reduction, nonlinear crosstalk/interference cancellation, and real-chip bring-up in lab.
Understand communication theories and signal processing related algorithms design such as timing recovery, signal estimation and detection, automatic gain control, channel estimation, equalization, coding theory, etc.
Knowledge in existing wireless communication protocols: 5G-NR or its early iterations, 802.11 WiFi, and/or Bluetooth/BLE.
Some relevant experience in circuit design.