Software Engineer, Wireless - Cellular

About this role

Software Engineer, Wireless - Cellular

Software Engineer, Wireless - Cellular

Bay Area, CA, United States

Job description

COMPANY OVERVIEW

Sigma Connectivity is a design house with a heritage in mobile phone development at Sony Ericsson and Sony. We are a team of 600 talented engineers with a main office in Lund, Southern Sweden. Primarily, we run in-house projects focused on connected products in consumer electronics and IoT. We have the capability in terms of people, expertise, and labs to realize the most demanding products on the market. In the US, we have operations in San Jose, San Diego, and Seattle. Our San Diego office is close to Palomar Airport in Carlsbad, and our San Jose office is just by the San Jose airport. As a fast-growing company, we are constantly looking for open-minded, talented people who want to join our journey. The Sigma Connectivity company culture is about sharing experiences and knowledge, and with a Scandinavian work culture, we strive for work-life balance and taking care of people. Within Sigma Connectivity, you will never work alone.

JOB OVERVIEW

The Sigma Connectivity is looking for an enthusiastic, hands-on Audio Electrical Engineer. The Wireless Software team builds the cellular, Wi-Fi, and Bluetooth software that keeps the vehicles online for over-the-air updates, emergency calling, remote commands, navigation, and streaming. We're hiring a senior cellular software engineer to own key parts of the in-vehicle 5G stack on the telematics platform used across several vehicle brands and shipped to markets worldwide. This is a hands-on IC role on embedded Linux and automotive 5G modems, working directly with modem suppliers, carriers, and our cloud connectivity team.

The points below describe a strong candidate; however, we highly value motivation, work ethic, and enthusiasm

RESPONSIBILIES

• Build and own the vehicle-side eSIM client: the GSMA 32 IoT profile assistant that downloads, enables, disables, and deletes carrier profiles on the embedded eUICC, integrated with our cloud eSIM manager (eIM) and connectivity management platform.
• Extend the cellular stack for multi-carrier, multi-region operation: carrier detection by MCC/MNC and per-carrier configuration of APNs, network selection, roaming, and recovery behavior, so new carriers and countries are added through configuration instead of code changes.
• Design and maintain the C++ services that control the modem and data path on embedded Linux, including registration state, concurrent data sessions on separate APNs for vehicle, media, and hotspot traffic, dual-stack IPv4/IPv6, and coordination with Wi-Fi for connection handoff.
• Make connectivity recover without user action: detect data stalls, registration rejects, out-of-service conditions, and modem initialization failures, apply tiered recovery, and keep the modem in a correct state through vehicle sleep, wake, and wake-on-network
• Own cellular observability and field triage: define telemetry for connectivity health, analyze modem diagnostic logs and fleet data, and drive modem and firmware defects to resolution with silicon and module vendors.Support the voice and emergency-call services that run on the cellular stack (IMS registration, emergency calling, SMS), working with the eCall team to root-cause call
• Write design docs and review code for the cellular subteam, mentor engineers, and set technical direction with partners in cloud, hardware and RF, systems engineering, test automation, and homologation.

Basic qualifications

Required Qualifications:

• BS in Computer Science, Electrical or Computer Engineering, or equivalent practical experience.
• 6+ years of embedded or systems software experience, including 3+ years on device-side cellular (LTE/5G) software that shipped in production devices such as telematics units, IoT modules, or phones.
• Strong modern C++ (C++17 or later) on embedded Linux: multithreaded services, state machines, IPC, and unit testing with GoogleTest/GoogleMock or similar.
• Host-side modem integration through vendor SDKs, QMI, AT commands, MBIM, or an Android RIL.
• Working knowledge of 3GPP device procedures: attach and registration (including reject causes), PDN/PDU sessions and APN configuration, PLMN selection, and roaming.
• Linux networking: IPv4/IPv6 dual-stack, policy routing, iptables/nftables, DNS/DHCP, and packet capture analysis with tcpdump or Wireshark.
• Experience debugging cellular issues from the field using modem diagnostic logs (QXDM/QCAT or equivalent), through to root cause in the application, modem firmware, or network.

Nice to Have:

• eSIM development: GSMA SGP.32, SGP.22, or SGP.02; eUICC ES10 interfaces and APDUs; IPA/LPA, SM-DP+, and eIM flows; bootstrap and operational profiles.
• Qualcomm automotive or IoT modem platforms, including the Qualcomm Telematics SDK.
• Carrier certification: carrier acceptance test plans in North America, Europe, or Asia-Pacific; GCF/PTCRB; carrier configuration files (MBN/PRI).
• IMS, VoLTE/VoNR, or emergency calling (eCall, NG-eCall, E911) on the device side.
• Multi-carrier, multi-SIM, or dual-modem products, and steering-of-roaming behavior.
• Automotive or other regulated embedded products: low-power modes, wake-on-network, homologation, and security requirements.
• Cellular test automation with network simulators (Keysight, Rohde & Schwarz, Anritsu, or similar), RF attenuation setups, and Python test frameworks.
• Yocto/BitBake or Bazel build systems.

Preferred additional skills, personal traits and experience

Soft Skills

• Strong problem-solving and analytical skills
• Ability to work in fast-paced, client-facing environments
• Excellent communication and collaboration skills
• Adaptability to changing requirements and priorities
• Team player
• Proactiveness in collaboration and execution
• Flexibility to switch technical context
• Willingness to learn new methods/tools/processes
• Ability to prioritize, multitask, and take ownership
• Strong problem-solving and critical-thinking skills
• Strong communication and interpersonal skills

We offer

• The annual salary range for this role is $150,000 – $175,000.
• The Annual Salary depends upon various job-related factors such as professional background, training, work experience, location, business needs, and market demand. This range is subject to change and may be modified in the future.
• Sigma Connectivity, Inc. also offers a comprehensive benefits package that includes the following:
• Paid Time off/Vacation and Paid Holidays
• 401(k)
• 401(k) matching
• Life insurance
• Flexible Spending Account (FSA): Healthcare and Dependent Care
• Health Savings Account (HSA)
• Paid Parental Leave
• Paid Bereavement Leave
• Employee Assistance Program
• Employee and Customer Referral Program
• For positions in California, long-term and short-term disability insurance

More information

For more information, please contact

DucoJan Pilot, [phone removed] [email removed]

• #### Position

Software Engineer, Wireless - Cellular

• #### Company

Sigma Connectivity Inc.

• #### Location

Bay Area, CA, United States

• #### Publication date

2026-11-02

• #### Contact

DucoJan Pilot, [email removed], +16692958400