Lawrence Der, Ph.D. Silicon Laboratories Inc. Introduction Edwin H. Armstrong, known as one of the founding fathers of radio technology, invented the superheterodyne radio receiver in 1918 and frequency modulation (FM) in 1933 [1]. These two concepts, along with his regenerative circuit technique developed in 1912, formed the basis of radio frequency electronics as we know it today. In the Unit...

Radio communications often take place in confined environments like city areas. The propagation channel presents shadowing and multipath phenomena due to interactions between radio wave and environment. In this work, a general hybrid channel model concept is proposed to associate the advantages of existing deterministic and statistical models. One of the model applications is introduced using a...

This paper presents the theoretical specification of Spectrum Sensing Receiver used for Cognitive Radios. Its system level design is intended to comply with IEEE 802.22, IEEE 802.16 (Wimax) and LTE standards altogether. The operation frequency band is very wide, from 50MHz to 3.8GHz. Calculated specifications include noise figure, compression point, third order intercept point, sensitivity and ...

We report on our progress and development of high speed flexible graphene field effect transistors (GFETs) with high electron and hole mobilities (~3000 cm/V·s), and intrinsic transit frequency in the microwave GHz regime. We also describe the design and fabrication of flexible graphene based radio frequency system. This RF communication system consists of graphite patch antenna at 2.4 GHz, gra...

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In this paper, we evaluate the performance of the Hybrid-MIMO Receiver Scheme (HMRS) in Cognitive Radio network (CR-network). We investigate the efficiency of the proposed scheme which the energy level and user number of primary user are varied according to the characteristic of CR-network. HMRS can allow users to transmit either Space-Time Block Code (STBC) or Spatial-Multiplexing (SM) streams...

A cognitive radio (CR) node is a radio device capable of operating (transmitting and receiving) over multiple channels. As a result, a network consisting of one or more cognitive radio nodes can adapt to varying channel availability in its geographical region by dynamically changing the channel (or channels) that nodes use for communication. We investigate the problem of neighbor discovery in a...

— This paper describes the optimization of spectrum sensing in terms of the throughput of a cognitive radio (CR) system. Dealing with the optimization problem of spectrum sensing, this paper evaluates the throughput of a CR system by considering such situations as the penalty time of a channel search and incumbent user (IU) detection delay caused by a missed detection of an incumbent signal. Al...

This paper proposes an adaptive digital receiver architecture suitable for Software Defined Radio systems. This receiver is prepared to handle modulation schemes whose symbols belong to a linear, twodimensional signal space (such as M-PSK or M-QAM). It is capable of identifying key signal parameters (e.g., symbol rate and constellation) and, in an autonomous way, modify its operation accordingl...