Adaptive Delta Compression for Automotive OTA | Excelfore

Over-the-air (OTA) software updates have become the backbone of the connected vehicle. From fixing bugs and enhancing safety features to introducing new features and options, OTA updates keep vehicles fresh long after they leave the factory floor.

But there’s a problem. Traditional full-image updates are large, costly, slow to download, and prone to disruption in real-world automotive environments. That’s why delta compression—and more specifically, Excelfore’s Adaptive Delta Compression—is now a game-changer for automotive OEMs.

What is Delta Compression?

At its core, delta compression (also sometimes referred to as differential updates) means transmitting only the changes (the deltas) between a new software version and the existing one, instead of sending an entire new code base.

• Full Update Example: 120MB file sent to every vehicle.
• Delta Update Example: Just an 8MB difference sent, reconstructed locally for the ECU.

This dramatically reduces bandwidth costs and download times. When scaled across millions of vehicles, the savings in cost and time are massive.

Excelfore’s Adaptive Delta Compression: Built for Automotive

Most OTA delta compression techniques were designed for smartphones, not cars. That’s a problem because vehicles bring unique challenges—dozens of ECUs, hardware variability, multiple OSs, connectivity gaps, and strict uptime requirements.

Excelfore’s Adaptive Delta Compression Engine addresses this with:

• Dynamic compression algorithms tailored for automotive workloads (patented US 8,949,466).
• Device-aware strategies that adapt to the specific computational power of each ECU.
• Policy-based optimization so OEMs can balance size reduction, bandwidth savings, and vehicle installation time.

The result: faster updates, reduced service costs, and a better customer experience.

Automotive-Specific Challenges in OTA Updates

Why is adaptive delta compression so critical? Because OTA in vehicles faces roadblocks not seen in consumer electronics:

• Inconsistent connectivity: Cars move through tunnels, cities, and remote areas with limited bandwidth.
• Hardware variability: A single vehicle can contain 50+ ECUs, with different levels of processing power and available memory space.
• User experience: Customers won’t accept long vehicle downtimes just to install updates.
• Data size: Full firmware images for individual ECUs can run into hundreds of MB, and full software images for infotainment systems or ADAS computers can run in many GB, driving up mobile network costs.

How Adaptive Delta Compression Solves These Issues

With adaptive delta compression, only the required differences are transmitted. But Excelfore goes further:

• Smart compression selection: The delta generation engine dynamically chooses the best compression strategy for the device based on OEM priorities and vehicle reconstruction resources.
• Reduced downtime: Updates can be reconstructed quickly without locking the vehicle for long periods.
• Lower costs: OEMs save on data transmission fees and service time.
  
  

Real-World Impact: Case Study in Action

A leading European EV manufacturer implemented Excelfore’s Adaptive Delta Compression Engine. 
The results were game-changing:

• 93% reduction in update size
• 86% savings on mobile bandwidth consumption
• Average update time cut from 15 minutes to under 4 minutes

This allowed the OEM to deploy updates globally without frustrating customers or straining networks.

Addressing Common OTA Limitations with Adaptive Delta Compression

Other delta update technologies often fail in real-world fleets. Excelfore’s approach overcomes these challenges:

• Base version mismatches: eSync always knows (and always verifies) which version of software is in the device before updating each ECU in each vehicle. With this information, deltas are tailored to the existing version in each ECU in each car, avoiding failures.
• Processing overhead: Compression strategies align with ECU resources.  Different delta algorithms are used depending on the reconstruction resources available in-vehicle, ensuring quick installations.
• Payload integrity verification: Whichever of the delta algorithms are used, eSync always verifies that the code installed in the target ECU is an exact match to the original (full) file uploaded to the eSync Server.  eSync with Adaptive Delta does not just ensure that the delta file will be delivered, but that the reconstructed code installed in the device will match the root of trust.
• Predictive scheduling: Updates can be timed to coincide with data tariffs and vehicle usage patterns.

Why Delta Compression is the Future of OTA

As cars become software-defined vehicles (SDVs), the volume and frequency of updates will only grow. Without adaptive delta compression, OEMs risk incurring high costs, delivering a poor customer experience, and experiencing inefficient update cycles.

By minimizing data transfer, ensuring compatibility, and reducing downtime, Excelfore’s solution makes OTA scalable, efficient, and customer-friendly.

FAQs

1. What is delta compression in automotive OTA?

 Delta compression (also called differential updating) is a technique that sends only the changes between two software versions, instead of transmitting the full new version. This reduces file size, airtime, and vehicle downtime.

2. How is adaptive delta compression different from standard delta compression?

Adaptive delta compression from Excelfore dynamically adjusts compression strategies based on each ECU’s capabilities and OEM priorities, ensuring faster, more reliable updates.

3. Why do carmakers need delta compression for OTA updates?

Vehicles often face bandwidth limitations and hardware diversity.  Delta compression ensures updates are lightweight, fast, and cost-efficient, without sacrificing user experience.

4. Does Adaptive Delta Compression improve customer satisfaction?

Yes. By reducing bandwidth costs and minimizing balancing download times and installation times, adaptive delta compression helps drivers enjoy a seamless update experience without interruptions.

5. Is delta compression secure?

Excelfore’s Adaptive Delta Compression is integrated with the eSync OTA platform, which uses secure cloud-to-vehicle communication protocols, ensuring updates are both efficient and protected.

Summary

Excelfore’s Adaptive Delta Compression Engine isn’t just an optimization—it’s a foundation for the future of automotive OTA.

• Less data cost.
• More customer satisfaction.

OEMs can now deliver updates at scale, without the bandwidth burden or user frustration.

Learn more about how Excelfore eSync optimizes OTA delivery. Contact us now.