Accurate and fast NB-IoT network measurements

Your task

Today’s LTE networks are optimized to deliver high data rates for multimedia services that require high bandwidth. The requirements for IoT use cases are different. LTE networks for IoT applications will be optimized for highest availability (deep indoor penetration) and lowest energy consumption. Unlike human beings, IoT installations such as smart meters installed in basements are unable to change position in order to obtain a better signal. Good network coverage is required to ensure a robust NB-IoT connection for the various NB-IoT applications.

Although NB-IoT is a 3GPP standard add-on to LTE, it represents a completely new radio system and coverage challenge. The following tasks are essential when planning and deploying new NB-IoT networks:

• Verifying NB-IoT RF coverage
• Ensuring NB-IoT service performance (QoS)
• Checking co-existence with other technologies (NB-IoT versus LTE/GSM)
• Troubleshooting in case of poor performance (QoS, QoE)
• Benchmarking to compare NB-IoT network coverage and other KPIs

For all these tasks, a powerful NB-IoT network test solution is essential.

Additional measurements are recommended to understand the device/network interaction, uplink behavior and protocol, signaling load and energy efficiency during NB-IoT communications.

T&M solution

Accurate NB-IoT coverage measurements are best executed with a network scanner with sufficient RF performance connected to state-of-the-art analysis software. You might think that this could be achieved by measuring with NB-IoT devices. However, an NB-IoT device only supports cell reselection measurements in idle mode, outside active discontinuous reception (DRX) and power saving mode (PSM) windows. An NB-IoT device will only measure neighbor cells if they are configured in the network and signaled in system information broadcast messages (SIB-NB 4 & 5). Consequently, accurate NB-IoT coverage measurements are best executed with a network scanner. There are still valuable measurements that can be obtained by using NB-IoT devices in addition to a scanning receiver as we shall see below.

NB-IoT network measurements based on NB-IoT devices help us understand device/network interaction, uplink behavior and protocol, signaling load and energy efficiency during NB-IoT communications:

• The accurate NB-IoT coverage solution consists of Rohde & Schwarz network scanners (R&S^®TSMW, R&S^®TSMA, R&S^®TSME) and R&S^®ROMES4 drive test software for network optimization and troubleshooting
• The complementary solution consisting of R&S^®ROMES4 software and NB-IoT devices (based on NB-IoT/eMTC chipsets from leading chipset companies) provides deep insight into the device/network interaction and the efficiency of IoT communications
• R&S^®ROMES4NPA problem analysis software analyzes both scanner and UE data

Results and key benefits

Rohde & Schwarz offers the only combined NB-IoT test solution with network scanners and NB-IoT devices connected to the analysis software from a single source.

The main benefits are:

• Intertechnology coexistence evaluated by using scanners with multitechnology capability: GSM, LTE, NB-IoT, spectrum, RF power scan, etc. The influence of NB-IoT on adjacent carriers/spectrum can be evaluated
• Accurate DL RF coverage information that can only be provided by network scanners
• Service performance measured with NB-IoT devices connected to R&S^®ROMES4
  • Application layer KPIs such as success rate, setup time, transfer time, user data rate and latency
  • Network performance metrics such as spectral efficiency, latency, energy efficiency, resource utilization and coverage (DL and UL)
• Variety of NB-IoT chipsets and module vendors supported
• Cost advantage through reuse of existing R&S^®TSMx scanner hardware (based on proven algorithms and scanner performance). The NB-IoT function is enabled via a software upgrade
• Faster drive/walk tests (more measurements in the same time) due to fastest LTE/GSM (multitechnology) scanning speed (with R&S^®TSMx) for evaluating the influence of NB-IoT carriers on LTE/GSM (OPEX advantage)
• More flexible use cases (walk tests possible) thanks to lightweight scanner hardware (▷ evaluation of NB-IoT carrier in basements (smart power meter), dense urban UE applications (i.e. parking meter)
  • Shoulder bag with R&S^®TSMA and R&S^®ROMES4 controlled by a tablet (small and lightweight measurement walk test solution for indoor/outdoor applications)
• Future-proof test solution: existing and future scanner products (R&S^®TSME, R&S^®TSMA, R&S^®TSMW) support NB-IoT scanning with the appropriate technology software option
• Frequency range: NB-IoT measurements on all bands up to 6 GHz
• Same look and feel/usability: NB-IoT will provide the same unique features as LTE and other technologies, such as automatic channel detection (ACD), and use similar GUI views to ease usability

Key features

Important features of our scanners in combination with the R&S^®ROMES4 analysis tool are measuring coverage (reference signal receive power, RSRP) and signal quality (carrier to interference and noise ratio, CINR). A scanner measures with much better RF accuracy than a commercial smartphone or an NB-IoT device. A scanner can measure the RSRP figures of all visible cells within the sensitivity and dynamic range threshold and at the same time provide deeper insight into all available NB-IoT cells (and accurate coverage).

The network scanners always work passively or non-intrusively, i.e. they do not affect the running network during the measurements.

The R&S^®ROMES4 software tool can also analyze data from connected NB-IoT devices. It provides deep insight into the communications between the NB-IoT network and the device with the NPA functionality (problem spot analysis for scanner and UE).