Comparison of delay spread measurements with ray tracing simulations at 1890 MHz

A wideband channel sounder is used to measure the complex impulse response of the radio channel, using a swept time delay cross correlator method. The sounder uses a chipping rate of 100 MHz, and has a resolution of 10 ns, equivalent to a path length difference of 3 metres. Omnidirectional vertically polarised antennas are used for both the transmitter and receiver. Indoor measurements are made in the Engineering School building, which has a mixture of small offices, and large open plan lab spaces, together with long corridors. Outdoor measurements are done within the campus, a compact collection of buildings of irregular shape. Ray tracing simulations are performed for the same environments using the personal computer-based Mirocell Communication Simulator (MCS), marketed by EDX Engineering, Inc., Oregon, USA. This simulator makes a number of simplifying assumptions, such as working only in two dimensions, and only allowing a one wall transmission per ray. Simplifying assumptions must also be made for the dielectric properties of the wall building materials. This paper compares simulated delay spreads with the measured values, in a variety of locations. An indoor measurement was done for a single receiver location within a large lecture room, with the transmitter in a nearby corridor. A series of indoor measurements was also done with the transmitter in a single location in a side corridor and the receiver moving along a route following a main corridor