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As the conventional QAM has a square constellation, PAPR is high due to the corner signal points. To overcome this, the (3 × 2m)-ary QAM with even m was proposed recently. For odd m, the rectangular constellation has high PAPR and perfect Gray code, while the diamond constellation has low PAPR and imperfect Gray code. In this paper, we propose a scheme assigning quasi-Gray code to the diamond constellation...
Fault tolerance is a major issue for all storage service providers. Currently, the storage service providers make use of data replication as a method to ensure fault tolerance. In the big data era, relying on data replication for fault tolerance reduces the storage efficiency. Most of the modern applications make use of erasure code based storage systems as an alternative to the data replication....
Efficient and robust wireless video delivery is an enabling technology for various applications. The existing wireless video transmission scheme has the cliff effect and it cann't gracefully adapt to channel variations. In this paper, we introduce a pseudo-analog wireless video transmission improvements and design in the hardware. Comparing with the traditional transmission, the linear processing...
This paper considers the layered transmission between the source and the destination over two relays using super-position coding (SC). In this two-hop decode-and-forward (DF) relaying system, because of the network topology, the receiver continuously decodes only the base layer of the direct transmission from the source; the enhancement layer is decoded with a delay based on the transmission from...
Efficient resource utilization with a satisfying quality of service is the key to high capacity in flexible optical networks. In our work, this is achieved by supporting the resource allocation with the Gaussian noise model, which estimates the nonlinear physical-layer impairments. The study includes variable launch power, modulation formats, error-correcting code rates, and various new network features...
Orthogonal frequency division multiplexing with index modulation (OFDM-IM) is a newly proposed technique, which achieves significantly improved performance in comparison with classical OFDM by using the indices of active subcarriers to carry additional information bits. In this paper, we propose two power allocation (PA) algorithms for the sake of further improving the bit error rate (BER) performance...
Interference forwarding by a relay enhances the interference level and enables the cancellation of the interference. If the interfering source to relay link is not strong, then the relay can decode a part of the interference and forward it to the destination, and the destination can cancel only that part of the interference. It is known as partial decode-and-forward (PDF) and partial interference...
Rise in wireless data traffics requires innovative interference management techniques to meet the demand. Transmit cooperation among multiple base stations has been proposed as a solution to this challenge and improve throughput. For base stations equipped with massive MIMO arrays, a proposed subspace encoding technique can decouple the joint multicell resource allocation problems into independent...
Anti-jamming is an important capability for satellite communication (SATCOM) systems, when critical communication links may need to be maintained in hostile environments with smart jammers trying to disrupt the communications. The protection of SATCOM links from intended radio frequency interference (RFI) is a complex task. Anti-jamming (AJ) can be done in multiple domains: space, time, frequency,...
In this paper, we investigate the physical-layer network coding (PNC) scheme based on successive interference cancellation (SIC) in multi-way relay channels (MWRC). We consider a scenario where all users simultaneously transmit signals to the relay in the up-link stage while the relay broadcasts a coded message in the down-link stage. In order to extract the network codes from superimposed signals...
In large-scale distributed computing clusters, such as Amazon EC2, there are several types of “system noise” that can result in major degradation of performance: system failures, bottlenecks due to limited communication bandwidth, latency due to straggler nodes, etc. On the other hand, these systems enjoy abundance of redundancy — a vast number of computing nodes and large storage capacity. There...
A cache-aided K-user Gaussian broadcast channel (BC) is considered. The transmitter has a library of N equal-rate files, from which each user demands one. The impact of the equal-capacity receiver cache memories on the minimum required transmit power to satisfy all user demands is studied. Decentralized caching with uniformly random demands is considered, and both the minimum average power (averaged...
Sparse superposition (SS) codes were originally proposed as a capacity-achieving communication scheme over the additive white Gaussian noise channel (AWGNC) [1]. Very recently, it was discovered that these codes are universal, in the sense that they achieve capacity over any memoryless channel under generalized approximate message-passing (GAMP) decoding [2], although this decoder has never been stated...
Robust linear analog block coding of a correlated Gaussian source over a Rayleigh fading channel, without encoderside channel-state information (CSI) is investigated. The encoder which minimizes the minimum mean square error, averaged over an ensemble of decoders whose channel gains are drawn from an exponential distribution is derived. This encoder does not require CSI. It is compared with a CSI-adaptive,...
In the fifth generation wireless networks, the heterogeneous deployment of ultra-dense small cells such as femtocells is seen as a major solution to cope with the exponential traffic growth and to improve coverage especially in indoor environments. However, the unplanned and ultra-dense deployment of femtocells in the coverage area of conventional macrocells introduces new challenges such as cross-tier...
From the probabilistic perspective, we present an analysis on potential incurred chances of division by “2” without reminder during a single process of the conjuncture of “3x + 1” in different sections of the binary expression of an input number. We revealed the difference of the tail section and the other parts for a large input number. Based on the ratio of the difference of the change of different...
Adaptive bitrate (ABR) streaming is the de facto solution in online video services to cope with heterogeneous devices and varying network connections. However, this solution is computation intensive, demanding a large number of servers for encoding videos. Moreover, due to the time-varying nature of video generation, intelligent strategies are required in order to determine the right amount of resources...
Distributed storage systems (DSSs) are widely employed in data centers and sensing networks to resist storage node failures. Structured redundancy is introduced to DSS by various coding schemes to efficiently account for failures of storage nodes. The allocation of the coded data blocks to storage nodes is another factor that impacts the data reliability. In this paper, we investigate the coding and...
This paper considers a K-user Gaussian broadcast channel (BC) where receivers are equipped with cache memories. Lower and upper bounds are established on the capacity-memory tradeoff, i.e., the largest rate achievable for given cache-memories. The lower bound is based on a joint cache-channel coding scheme which generalizes the recently proposed piggyback coding to Gaussian BCs with unequal cache...
To execute cloud computing tasks over a data center hosting hundreds of thousands of server nodes, it is natural to distribute computations across the nodes to take advantage of parallel processing. However, as we allocate more computing resources and further distribute the computations, a large amount of intermediate data must be moved between consecutive computation stages among the nodes, causing...
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