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Analog-to-digital converters based on sigma-delta modulation have shown promising performance, with steadily increasing bandwidth. However, associated with the increasing bandwidth is an increasing modulator sampling rate, which becomes costly to decimate in the digital domain. Several architectures exist for the digital decimation filter, and among the(More)
Low-density parity-check codes have recently received extensive attention as a forward error correction scheme in a wide area of applications. The decoding algorithm is inherently parallelizable, allowing communication at high speeds. One of the main disadvantages, however, is large memory requirements for interim storing of decoding data. In this paper, we(More)
Wireless communication standards are developed at an ever-increasing rate of pace, and significant amounts of effort is put into research for new communication methods and concepts. On the physical layer, such topics include MIMO, cooperative communication, and error control coding, whereas research on the medium access layer includes link control, network(More)
This paper presents some results of the FP7 ICT-LOLA (achieving LOw LAtency in wireless communications) project on the design of a clusterized wireless mesh network based on 3GPP LTE. First, we focus on the new MAC/PHY structure proposed. Then, the concept of virtual link is presented for inter-cluster communications combining MAC layer forwarding, hybrid(More)
In this work, we consider spectrum sensing of OFDM signals. We deal with the inevitable problem of a carrier frequency offset, and propose modifications to some state-of-the-art detectors to cope with that. Moreover, the (modified) detectors are implemented using GNU radio and USRP, and evaluated over a physical radio channel. Measurements show that all of(More)
Since their rediscovery in 1995, low-density parity-check (LDPC) codes have received wide-spread attention as practical capacity-approaching code candidates. It has been shown that the class of codes can perform arbitrarily close to the channel capacity, and LDPC codes are also used or suggested for a number of important current and future communication(More)
The use of rate-compatible error correcting codes offers several advantages as compared to the use of fixed-rate codes: a smooth adaptation to the channel conditions, the possibility of incremental Hybrid ARQ schemes, as well as simplified code representations in the encoder and decoder. In this paper, the implementation of a decoder for rate-compatible(More)
Abstract— A formulation based on multirate theory is introduced for analog-to-digital converters using parallel sigma-delta modulators in conjunction with modulation sequences. It is shown how the formulation can be used to analyze a system’s sensitivity to channel mismatch errors by means of circulant and pseudocirculant matrices. It is demonstrated how(More)