LTE Cat 1bis is a variation of LTE Cat 1 that uses a single receive (Rx) antenna, while retaining all other device characteristics such as uplink (UL) and downlink (DL) data rates and protocols unchanged. In contrast, standard LTE Cat 1 (3GPP Rel 8) features Rx diversity, which necessitates two Rx vias.
Rx diversity enhances RF reception, particularly at the cell edge. However, to facilitate Rx diversity, LTE Cat 1 chipsets need two RF inputs along with a complex RF front-end and dedicated software. This requirement partly explains why LTE Cat 1 chipsets are more expensive than those designed for LTE-M and NB-IoT. As a result, LTE Cat 1 applications often involve more complex and extensive PCBs, additional components, and dual antennas, leading to higher costs. For instance, an LTE Cat 1 solution might cost twice as much as its LTE-M counterpart.