Previous works have shown that multiple-input-multiple- output techniques such as space-time block code applied to tunnel environments present better performances than a single-input-single-output transmission, despite the small angular spread of the rays in this environment. Nevertheless, taking the guiding effect of the tunnel into account, one can wonder whether the simplest diversity schemes, in terms of complexity and implementation, may be a challenging solution, at least if compact arrays are used. The objective of this letter is thus to compare the performances of transmission schemes using diversity either at both ends of the link or at only the receiving side. The determination of symbol error rate is based on Monte Carlo simulations using channel matrices measured in a straight arched tunnel.
