IoT deployments now have access to more connectivity options than ever before. Typical selections now include not only the Gs of the cellular industry but sub-categories such as LTE Cat 1, narrowband-IoT and 5G RedCap. Each technology brings a new blend of performance and cost so LTE applications can match the connectivity with their use cases.

LTE Cat 1 bis is a variant of LTE that has been developed specifically to support IoT applications. Introduced within 3GPP Release 13, Cat 1 bis uses existing LTE networks but, critically, has been designed to operate with a single antenna, in contrast to LTE Cat 1 which requires that IoT devices have two antennas. This has obvious benefits in terms of enabling LTE Cat 1 bis devices to be more compact and cheaper than LTE Cat 1 devices. However, Cat 1 bis hardware can be more expensive than LTE-M and NB-IoT devices so it is practical mainly for use cases that can take advantage of the higher data rate to outweigh the lower costs of LTE-M and NB-IoT.

The bis name is not an acronym but instead a Latin word meaning ‘second time round’ which reflects the improvements Cat 1 bis brings in comparison to LTE Cat 1. An important benefit is that Cat 1 bis can offer the same data rate, latency, roaming capabilities and robustness as LTE Cat 1, even though it has a single antenna. In addition, Cat 1 bis uses the same infrastructure and standards as LTE Cat 1 so there is no need to rethink development approaches or introduce completely new technology.

In common with LTE Cat 1, Cat 1 bis offers 10Mbps downlink and 5Mbps uplink data rates, 20MHz bandwidth and latency of less than 100ms. These performance criteria set Cat 1 bis apart from other LTE variants that support single antenna designs including LTE Cat 0, LTE Cat M1 and LTE Cat NB1 (NB-IoT) which offer throughput of under 1Mbps. LTE Cat 1 bis therefore provides an attractive performance sweet spot for IoT applications that need greater performance than the lower end LTE variants while achieving form factor and cost advantages.

Adding Wi-Fi capability further extends the applicability of IoT devices and integration of LTE Cat 1 bis and MCU Wi-Fi is increasingly seen as a key means to ensure network availability, coverage, reliability, and power consumption requirements. This hybrid approach provides flexibility and ensures continuous connectivity even in challenging environments or when one network option is unavailable.

For example, IoT devices equipped with LTE Cat 1 bis and MCU Wi-Fi capabilities can initially connect to a Wi-Fi network for local communication and data exchange. If the Wi-Fi network becomes unavailable or if the device moves out of range, the device can seamlessly switch to LTE connectivity to maintain uninterrupted communication. Conversely, when the device comes back within range of a Wi-Fi network, it can automatically switch back to Wi-Fi connectivity to conserve cellular data usage and use the higher data speeds offered by Wi-Fi networks.

The complexities of this integration were explored in a recent Quectel Masterclass titled ‘Integration between LTE Cat 1 bis and MCU Wi-Fi’. The Masterclass, which was hosted by Lazaros Kapsias, Wi-Fi Product Manager EMEA at Quectel and Matija Saljic, an FAE at Quectel, shared the latest LTE Cat 1 bis and Wi-Fi product updates before explaining hardware integration and software integration techniques and providing a demo.

View the Masterclass, Integration between LTE Cat 1 bis and MCU Wi-Fi