Abstract--Promising approaches for efficient detection in multiple-input multiple-output (MIMO) wireless systems are based on sphere-decoding (SD). The conventional (and optimum) norm that is used to conduct the tree traversal step in SD is the -norm. It was, however, recently observed that using the -norm instead reduces the hardware complexity of SD considerably at only a marginal performance loss. These savings result from a reduction in the length of the critical path in the circuit and the silicon area required for metric computation, but are also, as observed previously through simulation results, a consequence of a reduction in the computational (i.e., algorithmic) complexity. The aim of this paper is an analytical performance and computational complexity analysis of -norm SD. For independent and identically distributed (i.i.d.) Rayleigh fading MIMO channels, we show that -norm SD achieves full diversity order with an asymptotic SNR gap, compared to -norm SD, that increases at m...