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In view of the defects that high range side lobes and high peak-to-average power radio (PAPR) in radar and communication integrated systems based on traditional orthogonal frequency division multiplexing (OFDM), a co-designed OFDM waveform based on Golay block coding for joint radar-communication system is proposed in this paper. The communication information is coded into Golay complementary sequences by Reed-Muller codes, which can not only reduce the PAPR of the system, but also can improve the error correction capability. However, the code rate of the algorithm will decrease rapidly with the increase of the number of subcarriers. Furthermore, the traditional block coding would impact on the final superimposed waveform performance due to phase randomness. Hence, a self-disarrange block coding algorithm is proposed. The radar and communication performance of the designed waveform, including wideband ambiguity function, range profile, PAPR, and bit error rate, is analyzed and simulated. The results demonstrate that the PAPR of the waveform and BER can be reduced effectively, while the range side lobes can be decreased for better radar detection performance.INDEX TERMS Integrated radar and communication, orthogonal frequency division multiplexing, Golay complementary sequence, peak-to-average power radio.

A novel scheme of an ultralow relative intensity noise (RIN) broadband source module employing a double pumped backward (DPB) Er-doped superfluorescence fiber source (EDSFS) and a semiconductor optical amplifier for interferometric fiber optic gyroscopes (IFOGs) is proposed. With optimized parameters, the optimal twin-peak output profile of the source is obtained. The effective optical spectrum width of the source is 38.6 nm, and the output power is about 12.5 mW. Compared with the DPB EDSFS with a similar spectrum, the ultralow RIN broadband source proposed demonstrates a lower RIN of about 8.4 dB. A high-precision IFOG utilizing the ultralow RIN broadband source is set up, and the performance of the IFOG is experimentally studied. An angle random walk coefficient of 6.93 × 10 − 5 o / h 1 / 2 is demonstrated, which is reduced by about 31.5% compared with the same IFOG system utilizing conventional DPB EDSFS with a similar spectrum profile. The ultralow RIN broadband source module proposed is quite feasible for high-precision IFOGs used in strategic-grade navigation systems and satellites.

The fruit and vegetable classification problem is an inseparable branch in the field of image recognition. GoogLeNet provides a more ideal solution for the fruit and vegetable classification problem. We use the GoogLeNet network to classify apples, lemons, oranges, pomegranates, tomatoes, and colored peppers. Through experiments, we obtained the training accuracy of GoogLeNet as 96.88%, the testing accuracy as 96%, and the training speed as 11.38 sheets/second. The recognition accuracy of this model can meet the basic recognition requirements, but the training speed is low. Therefore, we decided to optimize GoogLeNet to significantly improve the training speed and further enhance the recognition accuracy of GoogLeNet. We reduced the number of convolutional kernels of GoogLeNet and adjusted the structure of Inception, which reduced the number of parameters of GoogLeNet by nearly 48% and increased the training speed of GoogLeNet from 11.38 to 33.68 sheets/second. To further improve its recognition accuracy, we tried two methods: 1) introducing a new activation function Swish; 2) between convolutional layers, we introduced DropBlock layer; these two methods improved the testing accuracy of GoogLeNet by 2%. Finally, we introduce AlexNet, VGGNet, ResNet18, DenseNet121, and Inception-ResNet to compare with our optimized GoogLeNet. By comparison, we found that our model has incredible performance in ACC, AUC, FPS, Recall, etc.

Sparse code multiple access (SCMA) is one of the competitive non-orthogonal multiple access (NOMA) techniques for the next generation communication systems. In this paper, we put forward a simple and efficient design method named divided extended mother codebook (DEMC) to construct SCMA codebooks based on golden angle modulation (GAM) constellation points. First, we generate a vector defined by the GAM. Second, we design the extended mother codebook (EMC) by introducing the power and phase dependent constraints of symbols in multi-dimension codewords. The power constraints can ensure the power of each codeword is the same which leads to the optimal peak to average power ratio (PAPR) especially for the uplink channel. Third, we divide the EMC into several mother codebooks (MCs) to generate the constant bit rate (CBR) or variable bit rate (VBR) SCMA codebooks. The structure of the VBR SCMA codebooks is compatible with that of CBR. The VBR codebooks and CBR codebooks use the same factor graph, therefore, the users employed the VBR codebooks can also utilize the efficient message passing algorithm (MPA) for multi-user detection. Simulations reveal that the bit error rate (BER) performance of the proposed CBR DEMC-SCMA codebooks is outstanding with low complexity. The VBR DEMC-SCMA codebooks can flexibly satisfy the different service requirements, and the BER performance of the VBR DEMC-SCMA codebooks is close to each other though their modulation orders are various. This feature shows that the users can apply for a high order codebook to get a faster information transfer rate without increasing transmission power and bandwidth.INDEX TERMS sparse code multiple access (SCMA), constant bit rate (CBR) codebook, variable bit rate (VBR) codebook, design of dependent multi-dimension codeword