1. An adaptive quality control loop for a rate adaptation based on modulation and coding scheme (MCS) levels and multiple spreading codes, the adaptive quality control loop comprising in the step of: adjusting a first channel condition threshold based on a first error detection result for a first data packet transmission between a transmitter and a receiver using a first variable step, wherein the first channel condition threshold is associated with a first modulation and coding scheme (MCS) level used in the first data packet transmission.