NB-IoT Modulation Analysis 89600 VSA Software

NB-IoT Modulation Analysis 89600 VSA Software

Option BHT

• See through the complexity of 3GPP NB-IoT signals with a comprehensive set of tools for demodulation and vector signal analysis 
• Analyze downlink and uplink signals and derive signal quality: Overall EVM, EVM across symbols and subcarriers, constellations, IQ error plots and more 
• Use the color coding and marker coupling features to identify and isolate specific signal and channel effects and impairments

3GPP NB-IoT Air Interface

Although NB-IoT is incompatible with existing 3GPP devices, it inherits many LTE characteristics, such as the physical layer foundation and the higher layer architecture. The only duplex mode that has been standardized is Frequency Division Duplex (FDD); therefore, uplink and downlink use different frequencies. To reduce device complexity and cost, three major design decisions have been made. First, NB-IoT follows a half-duplex design so there is no need for expensive duplexer filters to isolate the transmit and receive chains; you can use a switch instead. Second, spatial multiplexing MIMO is not supported, and therefore UE is only required to implement one receiver chain. Finally, and very importantly, the channel bandwidth is only 180 kHz, which reduces the overall platform cost.

Deployment Modes

Three different deployment modes have been defined for NB-IoT to enable deployment in any available spectrum greater than 180 kHz. The three modes are shown in Figure 1. Stand-alone enables deployment in spectrum of its own, for example, in spectrum reframed from GSM. Guard-band enables deployment within the guard band of an LTE carrier with guaranteed co-existence. In-band enables deployment within an LTE carrier. This is the optimal approach for LTE operators, as it has the most efficient spectrum utilization and is a lower cost approach to support NB-IoT in existing LTE carriers. In this case, the NB-IoT carrier is embedded in the LTE signal by replacing one of the available LTE Physical Resource Blocks (PRB) without causing any disruption in the LTE operation.

NB-IoT Modulation Analysis

The 89600 VSA software’s option BHT provides comprehensive analysis capabilities in the frequency, time, and modulation domains for signals based on 3GPP specification (www.3gpp.org) The software provides frequency-, time-, and modulation-domain analysis results in a single measurement. By configuring result traces of spectrum, acquisition time, and NB-IoT specific modulation quality traces and tables, engineers can identify overall signal characteristics and troubleshoot intermittent error peaks or repeated synchronization failures. For automated testing, .NET API and SCPI remote interfaces are available to accelerate design, which enables quicker transition to the design verification and manufacturing phases. NB-IoT is among over 75 signal standards and modulation types supported by the 89600 VSA software. The software is a comprehensive set of tools for demodulation and vector signal analysis. These tools enable you to explore virtually every facet of a signal and optimize even the most advanced designs. As you assess your design tradeoffs, the 89600 VSA helps you cut through the complexity.