Self-adapting bit power allocation method based on bit preallocation

The invention relates to a self-adapting bit power allocation method based on bit preallocation, which comprises the following four steps: step one: instantaneous CSI estimation; step two: bit preallocation; step three: bit unit single-step allocation; and step four: calculations of a power formula 1 of each subcarrier and a total power formula 2. The method uses a bit preallocation strategy to preallocate part of the bits to a subchannel of which the subchannel gain is larger than the average channel gain to avoid part of the iterative processes; and simultaneously, a preestablished index table can look up a table to take out f (Cn(i)) to avoid repeated calculations in each iterative process, reduce the algorithm complexity to great extent and improve the operational speed, thus the method is quite applicable to systems with high real-time requirement. On the other hand, after the bit preallocation, a greedy algorithm is further used for allocating the remaining bits so that the method has high transmission