1. A method for adaptive transmission signal detection in a communication system, the method comprising: receiving a reception signal vector; estimating, by a processor, a channel matrix of a channel that the reception signal vector experienced; performing, by the processor, QR decomposition based on the estimated channel matrix; calculating dimensions of divisional spaces adaptively on the basis of a signal-to-noise ratio (SNR) or a signal-to-interference noise ratio (SINR); detecting, by the processor, a maximum likelihood point having a maximum likelihood value among lattice points within each divisional space obtained on the basis of results from performing the QR decomposition and calculating the dimensions of the divisional spaces; and recovering, by the processor, a transmission signal vector based on the detected maximum likelihood points.