Jinkang Zhu - IEEE Xplore Author Profile

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With user collision being the main concern for massive random access, non-orthogonal multiple access (NOMA) is an important tool to address the issue because it allows users to share the same channel resources. However, more refined access control schemes are expected in consideration of the explosively increasing traffic in modern communication systems. In this paper, we aim to maximize the acces...Show More
To enable the base station to serve more users, we implement multiple-input multiple-output non-orthogonal multiple access, which is capable of serving multiple users with a single beam. Therefore, it is crucial to group users according to their channel correlation before performing beamforming. Heuristic methods are commonly used, as the user clustering problem is NP-hard. However, these methods ...Show More
Rydberg atomic sensors have been seen as a novel radio frequency (RF) measurements and the high sensitivity to a large range of frequencies makes it attractive for communications reception. Based on Lindblad master equation, we discuss the steady state response and bandwidth of four-level Rydberg atomic system under amplitude modulation (AM) signal. Then, we investigate the effect of laser powers ...Show More
In this paper, we propose a nonorthogonal downlink multiple access scheme, where the base station assigns the bit streams to different users from an adjustable hierarchical quadrature-amplitude-modulation (QAM) constellation and all users deploy a simple non-iterative receiver with the same complexity as in an orthogonal multiple access (OMA) system. We analyze the achievable information rates of ...Show More
In resource constrained wireless networks, federated learning (FL) will meet a certain degree of heterogeneity, such as the non independent and identically distributed (non-i.i.d) data, the various communication schemes, the different computation capabilities of massive network users. Under these heterogeneity, the convergence latency of the global model built by FL may increase. Therefore, we fir...Show More
Satellite mobile system and space-air- ground integrated network have a prominent superiority in global coverage which plays a critical role in remote and non-land regions, as well as emergency communications. However, due to the gradual angle attenuations of the satellite antennas, it is difficult to achieve full frequency multiplex among different beams as terrestrial 5G network. Multi-color fre...Show More
Facing the development of future 5G, the emerging technologies such as Internet of things, big data, cloud computing, and artificial intelligence is enhancing an explosive growth in data traffic. Radical changes in communication theory and implement technologies, the wireless communications and wireless networks have entered a new era. Among them, wireless big data (WBD) has tremendous value, and ...Show More
In this paper, we focus on the delay constrained scheduling problem for wireless link communication under the practical concerns, such as the practical power consumption of transmitter and energy used for channel estimation. In particular, we target to design an energy-efficient scheduling policy that minimizes the total energy expenditure while satisfying the deadline constraint based on knowledg...Show More
A new cognitive mobile communication system (CCMCS) is proposed in this paper, which can utilize the unlicensed frequency sufficiently, protect the investment of networks existed and support its evolution. Through the effective application of variable-band OFDM and multiband OFDM, the system can connect several narrowbands into a wideband, and support high speed data transmit. Synchronization to t...Show More
In an effort to utilize the advantage of using multiple antennas, transmit antenna selection for linear dispersion codes (LDC-TAS) is proposed in this paper. We present three criteria: maximum channel gain, maximum capacity and max-min post-SNR, for selecting the optimal transmit antennas when linear, coherent receiver is used over a slowly varying channel. Simulation results suggest that the max-...Show More
V-BLAST(Vertical Bell Lab Layered Space-time) is an attracting space-time code structure because it can get significantly higher capacity than SISO system in Rayleigh fading environments. To optimize ber, computational complexity, time delay or other targets, many different detection algorithms are proposed in recent years. In this paper, we proposed a two-stage detection algorithm for V-BLAST, in...Show More
In this letter, we present a linear-complexity encoding algorithm for any cycle GF(2/sup P/) code C/sub E/(G,H). We just need to investigate the case where G is a nontrivial connected graph. If G is a tree, the only codeword is the all-zero word. If G is not a tree, first, we show that through graph analysis H can be transformed into an equivalent block-diagonal upper-triangular form simply by per...Show More
A low complexity per-antenna power control (PAPC) approach based on minimum mean squared error (MMSE) detector for V-BLAST is proposed in this paper. The PAPC approach is for minimum bit error rate (BER) averaged over all substreams, when the data throughput and the total transmit power keeps constant over time. Simulation results show that the power-controlled V-BLAST (P-BLAST) outperforms the co...Show More
A new scheme, selective time domain filtering, that has significantly reduced complexity compared to the SLM scheme, which only relies on conventional channel estimation and demodulation techniques for multipath fading channels to recover the data, is proposed. Computer simulations indicate that the new scheme suffers only a small loss in performance in exchange for significant reduction in comple...Show More
In this paper, the impulse radio (IR) system of pulse position amplitude modulation (PPAM) using an orthogonal sinusoidal correlation receiver (OSCR) is proposed. PPAM combines pulse position modulation (PPM) with pulse amplitude modulation (PAM) to provide higher data throughput with low computational complexity. But the performance of PPAM is considerably sensitive to timing jitter. OSCR has rem...Show More
In the multiple antenna multiuser systems, multiuser diversity technique is a simple but practical technique to increase system throughput, especially when many users exist. This, however, may cost too much radio resource for the feedback request of channel quality metrics for each user in every slot. By investigating the throughput performance of multiuser diversity system with random beamforming...Show More
In this article, we propose a blind synchronization algorithm for the uplink OFDMA system. The algorithm exploits the second-order cyclostationarity of the received signal, to estimate the frequency offset and time delay under the different subcarrier allocation schemes. The performance of high resolution and immune to the effect of noise and interference is evaluated through simulation results.Show More
Pilot subcarriers based channel estimation is necessary in high rate and high speed OFDM systems. In this paper, we present a new channel estimation and delay tracking method in a SAGE (space alternating generalized expectation maximization) framework. The proposed method uses much fewer pilots with special positions that are related to the path number and path delays. The method considered not on...Show More
A blind uplink synchronization algorithm of multiuser OFDM system is introduced in this article. The algorithm exploits the second-order cyclostationarity of the received signal, to estimate the carrier frequency offset and symbol time delay of every user. And a modified frequency offset estimation algorithm based on second-order conjugate cyclostationarity is proposed too. The characteristic of h...Show More
In this paper, we extend the traditional SNR estimation algorithms defined in complex AGWN channel to time variant linear channel and present a new SNR estimation algorithm for OFDM system. We compare our algorithm with two moment-based algorithms. Simulation results show that the new algorithm performs better in large Doppler frequency environments and is insensitive to the statistical characteri...Show More
In this paper a novel time and frequency synchronization method for orthogonal frequency-division multiplexing (OFDM) system is proposed. Preamble symbols are not used for synchronization like traditional solutions, thus the overhead of preambles can be eliminated and the spectrum efficiency of the system can be increased greatly, especially for short data bursts. It uses the cyclic prefix for coa...Show More
A closed-form expression for the pairwise error probability of cyclic unitary space-time codes with t=2 and r=1 is obtained. Additionally, this result is used to obtain an upper bound to the symbol error rate of cyclic unitary differential space-time group codes. It is also shown that these techniques can be used to approximate the symbol error rate of dicyclic unitary differential space-time grou...Show More
The multi-carrier (MC) CDMA technique can reduce the interference and improve the performance of the system in fading channels. In this paper, to transmit high rate data, an improved novel M-ary MC-CDMA technique is proposed, which offers a much higher spectral efficiency. We give numerical results of the performance analysis and comparisons of conventional MC-CDMA schemes with the proposed M-ary ...Show More
In this paper, we propose a new frequency synchronization method for wireless orthogonal frequency division multiplexing (OFDM) systems. The method exploits the pilots' energy efficiently by collecting the energy leaked into the neighbor subcarriers, and provides the coarse and fine estimation of the frequency offset at the same time. Furthermore, an adaptive accumulator is used to attain a good t...Show More