Site Survey for Wireless Communications Evaluation for New York Mercantile Exchange

The New York Mercantile Exchange (NYMEX) asked Texas Instruments (TI) to study and propose the implementation of a system to support commodities traders in the exchange trading pits. The system includes a custom hand held computer, an integrated wireless communications system, a wireless-to-wired network bridge, and a fault detection and recovery scheme. This paper summarizes the findings of a site survey on the trading floor at NYMEX both during off hours (“empty room” but with existing equipment) and during trading (hundreds of traders in constant motion present). The goal was to evaluate the system sensitivity and impact of the impairments in terms of friendly and external interferers. Using a spectrum analyzer and a tracking generator, we measured the real-time path loss and frequency response from the temporary access point to the hand-held computer. Measurements of the indoor propagation path loss at NYMEX show good correlation with theory. Due to the large number of metal structures and plasma displays there is significant multi-path throughout the room and, hence, very little shadowing. With a location 100 floors below the World Trade Center broadcast center, the NYMEX commodities floor is a particularly interesting environment from an external interferer standpoint (i.e. intermodulation suppression, adjacent channel rejection). In addition, the excessive trader activity and user density in a hyper-active physical environment places several constraints on communication system design.