به نام خدا
Title: Minimizing Transmit Power for Cooperative Multicell System with Massive MIMO
Authors: Jinkyu Kang and Joonhyuk Kang
Abstract: We consider the problem of designing transmit beam former and power for downlink cooperative base-station(BS) system with a large antenna arrays. Since the design of the beam forming vector at the transmitter requires high computational complexity, in a large antenna arrays, we utilize the zero-forcing transmit beamformer, which is the simplest form and the optimal performance in a large antenna arrays. Therefore, this paper focuses on the design of power allocation with n¼üxed transmit beam former for minimizing the transmit power while meeting target signal-to-interference-and-noise-ratio(SINR) of each user and power constraints. We consider two scenarios according to the power constraints of cooperative BSs.One scenario is the sum power constraint on the cooperative base-stations. In this case, the cooperative BSs share the total available transmit power. However, each BS exists a maximum availabletransmit power in practical implementations. Thus, we consider amore realistic per BS power constraints. We proposed the solution strategies for both scenarios: For the sum power constraint case,a simple intuitive solution, where the power is allocated withoutregard to the power constraint until the SINR constraints issatisn¼üed, is presented. For the per BS power constraints case, weuse the properties of a large antenna arrays to n¼ünd the solution ofclosed form. We also demonstrate, via numerical simulation, the performance of proposed strategy is convergent to the optimal performance which is achieved by using the iterative algorithm.
Publish Year: 2013
Published in: CCNC - IEEE
Number of Pages: 5
موضوع: الکترونیک
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به نام خدا
Title: Slender-Set Differential Cryptanalysis
Authors: Julia Borghoff, Lars R Knudsen, Gregor Leander, and Sren S Thomsen
Abstract: This paper considers PRESENT-like ciphers with key-dependent S-boxes. We focus on the setting where the same selection of S-boxes is used in every round. One particular variant with 16 rounds, proposed in 2009, is broken in practice in a chosen plaintext/chosen cipher text scenario. Extrapolating these results suggests that up to 28 rounds of such ciphers can be broken. Furthermore, we outline how our attack strategy can be applied to an extreme case where the S-boxes are chosen uniformly at random for each round, and where the bit permutation is key-dependent as well.
Publish Year: 2013
Published in: Journal of Cryptography - Journal of Springer
Number of Pages: 28
موضوع: رمزنگاری (Cryptography)
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