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We present round-efficient protocols for secure multi-party computation with a dishonest majority that rely on black-box access to the underlying primitives. Our main contributions are as follows: · a O(log* n)-round protocol that relies on black-box access to dense cryptosystems, homomorphic encryption schemes, or lossy encryption schemes. This improves upon the recent O(1)log* n-round protocol of...
Several adaptation approaches, such as policy-based and reinforcement learning, have been devised to ensure end-to-end quality-of-service (QoS) for enterprise distributed systems in dynamic operating environments. Not all approaches are applicable for distributed real-time and embedded (DRE) systems, however, which have stringent accuracy, timeliness, and development complexity requirements. Supervised...
In this paper, a class of quasi-orthogonal space-time block codes (Q-STBC) is proposed for systems with 2 antennas and 3 time slots, where the orthogonal Alamouti code can not be applied due to the “odd symbol” problem inherited in the 3GPP frame structure. The proposed codes can achieve rate one and full diversity with lower complexity maximum likelihood detection. The design takes into consideration...
In this work we study a two-user multiple antenna system under quasi-static fading employing a novel scheme that combines cooperation and iterative multiuser detection based on minimum mean square error estimation. We investigate three different receivers: a joint detector for the two users, a separate (per-user) detector, and a distributed matrix-Alamouti detector. We show that the separate detector...
An OFDM system with dual windowing is proposed as the physical layer for cognitive radios. This system can create deep spectrum notches to avoid interference to primary user, while maintaining high performance and low complexity.
Bit-interleaved coded modulation with iterative decoding (BICM-ID) performs well under a variety of channel conditions. Based on a factor graph representation of BICM-ID, we propose a modification of the BICM-ID receiver that can reduce the computational complexity significantly without BER degredation. The basic idea is to avoid updates of code bit log-likelihood ratios whose magnitude is already...
Delay jitter in packet-switched networks has to be compensated by a playout buffer. The playout buffer algorithm plays an important role in real-time applications such as VoIP, in this, paper we introduce a method based on truncated Gaussians to calculate the playout delay for VoIP application. Our method out-performs the existing methods both in term of residual delay and packet loss. This method...
Here, we propose a novel tree based interleaver (TBI) for generating user specific chip-level interleaving sequences for various users in an IDMA system, which reduces computational complexity drastically. This interleaver also solves the memory cost problem and reduces the amount of information exchange between mobile stations and base stations required to specify the interleaver. Simulation results...
The demands for high data rates and spectrally efficient modulation techniques are increasing due to the evolution of multimedia service in wireless communication systems. Bit-interleaved coded modulation with iterative decoding (BICM-ID) is a bandwidth efficient transmission scheme, which is suitable for next-generation wireless communication systems. In order to exploit the time-varying nature of...
Owing to the error propagation, the performance of VBLAST is constrained by the accuracy of the symbols recovered in the previous layer when the traditional detection successive interference cancellation (SIC) algorithm is applied. The performance of VBLAST depends on the performance of the first detected layer. So we proposed a new detection scheme that the first stage is detected with iterative...
This paper explains how a windowing of the OFDMSignal in the time domain contributes to its improved reception. The windowing uses the part of the guard interval that is not disturbed by multipath reception. The length of the window adapts to the transmission conditions. This window may be realized with a raised cosine or other kind of function that fulJills the nyquist criterion. An easy way to implement...
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