Open RAN in 2026: Why Multi-Vendor Multiplies the Need for Field Testing

Deutsche Telekom is issuing an RFQ for 30,000 Open RAN sites. AT&T has exceeded 50% of its traffic on open-capable hardware and is testing Cloud RAN in two cities. Samsung signs with Rakuten Mobile and expands its partnership with Orange in Europe. Open RAN revenue grew at double digits in 2025 after a 40% decline.

Open RAN is moving from concept to production. And with it comes a problem nobody wants to see: multi-vendor field validation.

The Fundamental Open RAN Problem

One Site, Multiple Vendors, No Guarantee

In a traditional RAN network (Ericsson, Nokia, Huawei), a single vendor provides the entire radio chain: radio unit (RU), distributed unit (DU), centralized unit (CU), and the software connecting them. Integration is guaranteed by the vendor. Responsibility is clear.

In Open RAN, the principle is reversed:

• The RU can come from Fujitsu, Samsung, or a new entrant
• The DU/CU can run on Dell or HPE hardware with Mavenir, Parallel Wireless or Wind River software
• The RIC (RAN Intelligent Controller) is a separate component with its own xApps/rApps
• Orchestration is handled by an independent software layer

Each interface (fronthaul, midhaul, E2, A1, O1) is specified by the O-RAN Alliance. But a specification is not an implementation. And an implementation tested in a lab is not one that works in the field.

Real Problems in Production

Field experience from early Open RAN deployments reveals multi-vendor-specific problem categories:

Radio Interoperability

• Fronthaul desynchronization between RU and DU from different vendors
• Interpretation gaps in O-RAN specifications for MAC scheduling
• Degraded beamforming when RU and DU do not share the same proprietary algorithms

Performance

• 15-20% lower throughput than single-vendor solutions in certain configurations
• Increased fronthaul (eCPRI) latency when implementations differ
• Slower inter-frequency handovers in multi-vendor environments

Stability

• RU resets after DU software updates (version incompatibility)
• Temporal synchronization loss (PTP/SyncE) between components
• Random RIC behavior when interacting with DUs from different vendors

Why Field Validation Is Irreplaceable

Labs Do Not Reproduce the Field

Open RAN Test and Integration Centers (OTICs) and operator labs test interoperability under controlled conditions. But the field adds variables that labs cannot simulate:

• Real propagation: RF conditions in the field (interference, multipath, indoor attenuation) stress radio algorithms unpredictably
• Real load: behavior under thousands of simultaneous users differs from behavior with 10 test UEs
• Mobility: handovers during real movement (car, train) test DU-CU interactions under strict timing constraints
• Temperature and environment: Open RAN hardware (outdoor RU, DU servers in shelters) reacts differently depending on physical environment

7 Open RAN Field Validation KPIs

A field validation campaign must cover KPIs specific to the multi-vendor context:

1. Throughput per cell and per sector Compare each cell’s performance against vendor specifications and equivalent single-vendor benchmarks. Acceptable gap: < 10%.

2. End-to-end latency (user plane) Measure real end-to-end latency, including fronthaul processing. In Open RAN, the 7.2x split adds strict timing constraints on the fronthaul.

3. Intra and inter-vendor handover rate If one cluster uses Fujitsu RUs and the neighboring cluster uses Samsung RUs, the handover between them is the critical point. Measure success rate and interruption time.

4. Stability under load Test performance under progressive load (100, 500, 1000+ UEs) to identify degradation thresholds. Open RAN implementations are often optimized for nominal cases, not worst case.

5. RIC behavior If the RIC deploys optimization xApps (traffic steering, load balancing), verify in the field that RIC decisions are consistent with real RF conditions.

6. Temporal synchronization Measure PTP/SyncE precision in the field. Synchronization drift > 1.5 microseconds on the fronthaul degrades MIMO and beamforming performance.

7. Inter-vendor Layer 3 analysis RRC message decoding verifies that cell configuration parameters (SIB, MeasConfig, Reconfiguration) are consistent between cells from different vendors. Inconsistencies cause handover ping-pong, excessive reselections, or connection drops.

Field Diagnostics in the Open RAN Ecosystem

What OSS Tools Do Not See

OSS platforms (SMO: Service Management and Orchestration) collect KPIs from DU/CU via the O1 interface. But these KPIs are aggregated, averaged, and viewed from the network side.

Field diagnostics sees from the terminal. And that is a radically different perspective:

• The OSS sees a successful handover. The field sees it took 150 ms instead of 30 ms.
• The OSS sees an average throughput of 200 Mbps. The field sees that 30% of users are at 50 Mbps due to unfair scheduling.
• The OSS sees a RIC optimizing. The field sees the RIC optimization creating handover ping-pong in a specific zone.

Vendor Independence: An Imperative

This is the Open RAN paradox: it promises vendor independence, but most test tools are tied to a vendor. Testing a Nokia+Samsung+Mavenir network with a Nokia tool is a technical conflict of interest.

An independent field diagnostic tool, operating at the Qualcomm chipset level (DIAG protocol), has no vendor bias. It measures what the terminal sees, not what the vendor wants to show.

Field Validation Methodology

Phase 1: Pre-Deployment Benchmark

Before Open RAN deployment, measure existing single-vendor network performance in the same zones. This benchmark becomes the comparison reference.

Phase 2: Site-by-Site Acceptance

Each Open RAN site must be validated individually:

• RF coverage verification (RSRP, RSRQ, SINR per sector)
• Throughput test per cell
• Layer 3 analysis of broadcast parameters (SIB) and configuration
• Intra-site handover verification (between sectors)

Phase 3: Inter-Vendor Validation

Test transitions between zones managed by different vendors:

• Inter-cluster handover
• Data and voice service continuity
• Mobility parameter consistency (measurement gaps, offsets, hysteresis)

Phase 4: Load and Stability Testing

Simulate or measure under real load conditions:

• Peak hours
• Events (stadium, concert, train station)
• Behavior under degradation (component loss)

Phase 5: Continuous Post-Deployment Monitoring

Open RAN evolves continuously (frequent software updates). Each DU, CU or RIC update must be followed by a field verification campaign to confirm no regression.

The Niche Nobody Occupies Clearly

No market player positions clearly on multi-vendor Open RAN field validation on smartphone. Existing solutions are either:

• Tied to a vendor (Nokia, Ericsson): conflict of interest in multi-vendor context
• Too expensive (Keysight, R&S): unsuitable for the volume of sites to test (30,000 for DT alone)
• Too shallow (crowdsourcing, Speedtest): no Layer 3, no protocol analysis

Open RAN field validation needs a tool that combines:

• Vendor independence (no link to the RAN vendor)
• Protocol depth (Layer 3 decoding)
• Scalability (smartphone deployment, not $50,000 hardware)
• Controlled cost (proportional to site volume)

This is an emerging market niche, directly tied to Open RAN growth, set to explode with Deutsche Telekom’s 30,000 sites and Orange and AT&T deployments.

Open RAN promises openness. But openness without validation is a gamble. And in the field, gambles are measured in KPIs, not PowerPoints.