Self adaptable transmission for OFDMA system

An orthogonal frequency division multiple access and adaptive transmission technology, which is applied in the field of OFDM cellular mobile communication system transmission, can solve the problems of poor adaptive modulation performance, limited channel correlation, and large channel correlation, etc., to achieve improved error Bit rate performance, improved throughput, and low complexity effects
CN1585392AActive Publication Date: 2005-02-23SOUTHEAST UNIV
0 Cites 28 Cited by

Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
SOUTHEAST UNIV
Publication Date
2005-02-23

Smart Images

  • Figure 1
    Figure 1
  • Figure 2
    Figure 2
  • Figure 3
    Figure 3
Patent Text Reader

Abstract

The method includes following steps: 1) the system is initialized; the numbers of cyclic prefix inserted into OFDM system are selected by actual measurement of multi path time delay; according to the cyclic prefix, the frequency inserted into by the frequency domain pilot frequency is determined ; 2) SINAD threshold of each kind modulation mode like BPSK, QPSK, 16QAM, 64QAM is set by high layer protocol, the SINAD value obtained from step 1 is compared with the threshold corresponding to each modulation mode; 3) Doppler shift is estimated out, it is decided that the product of Doppler shift and frame length is which range; 4) for first sub-carrier in each group, the modulation mode is presented by using GRAY CODE, the transmission of signal uses 4 bit; 5) the transmitting end assigns the modulation mode to next frame data according to received TMC instruction.
Need to check novelty before this filing date? Find Prior Art

Description

technical field

[0001] The invention relates to an adaptive transmission scheme for an Orthogonal Frequency Division Multiple Access (OFDM) cellular mobile communication system, and belongs to the transmission technical field of the OFDM cellular mobile communication system. Background technique

[0002] The ever-increasing demand for wireless multimedia services requires reliable high-speed data communication over wireless channels. The main problem of broadband transmission under mobile multipath channels lies in the ability to resist Inter-symbol Interference (ISI). Multi-carrier communication has attracted great interest due to its ability to resist inter-symbol interference. As a kind of multi-carrier communication technology, OFDM has broad prospects. OFDM is a parallel transmission method that uses many subcarriers to transmit information symbols in parallel to reduce the symbol rate, so that each subcarrier experiences a flat fading chann...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More