| 摘要 |
<p>The invention provides a method for sending user signals in an OFDMA system which includes: all the time-frequency grids of each time slot are divided into sub-channels; each sub-channel includes Nf sub-carriers overlapped in the time domain, wherein Nf~4; in each sub-channel, the maximum of frequency interval between a sub-carrier and its neighbor is three times no less than the minimum of that; when the user message is sent, the modulated signal is produced according to the user message; the grid set of time-frequency is the union of at least one sub-channel, which is allocated for the user, the number of sub-channels is determined based on the size of the user message, and the time-frequency positions of sub-channels are chosen according to the predetermined rule; the modulated signal is mapped to the grid set of time-frequency allocated for it, and the signal of frequency domain is produced; the Inverse Fast Fourier Transform is used to transform the signal of frequency domain into the signal of time domain and the signal of time domain is sent. This invention also provides the corresponding method for receiving user signal, device for sending user signal, device for receiving user signal, and access system, and improves the receptivity.</p> |
