Analysis of the Performance Boundaries of Sub-1 GHz WLANs in the 920MHz ISM-Band

We explore the performance boundaries of sub-1 GHz Wireless Local Area Networks (WLANs) and summarize the limitations of our proposed narrow-band WLAN system that uses carrier frequencies at 920 MHz with 1 MHz channel bandwidth. While there are several evaluation reports on WLAN testbeds available, no report is available that discusses the boundaries of narrow-band multiple-input multiple-output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) WLANs in sub-1 GHz. Even though 2.4 GHz/5 GHz MIMO-OFDM WLANs have been widely investigated, the characteristics of narrow-band WLAN is different from that of existing studies. This is mainly the result of limited channel bandwidth at lower frequency bands. This paper covers both, the fundamental performance boundaries for sub-1 GHz WLANs, and measurement results of our proposed software-based 2x2 MIMO-OFDM sub-1 GHz WLAN system operating at 920 MHz in order to identify the performance regimes, when using transmission protocols, including ICMP, UDP, and TCP.