a base station communication module and a customer premise equipment communication module are adapted to implement a method for selecting a modulation and coding scheme . the method for selecting an mcs includes the following steps : receiving a plurality of first packets in a first period , and calculating a packet error rate ; determining whether the per is greater than an error rate threshold ; and when the per is greater than the error rate threshold , performing the following steps : obtaining a carrier to interference plus noise ratio return value ; performing an adjusting procedure to obtain a cinr adjustment value ; calculating an actual return value according to the cinr return value and the cinr adjustment value ; and selecting one of a plurality of mcss according to the actual return value .