Subchannel data updating of high-order modulation format signals using cascaded sum- and difference-frequency generation in a single periodically poled lithium niobate waveguide is demonstrated. One quadrature phase-shift-keying subchannel of a 16-quadrature amplitude modulation (QAM) signal at 40 Gbit/s is successfully updated, with an optical signal-to-noise ratio (OSNR) penalty of ~2 dB for ...

Inorder to enhance the capacity and output of a downlink orthogonal frequency division multiple access(OFDMA) network, it is essential to perform appropriate resource allocation. Correct resource allocation suggests that finding best subchannel and power allocation for each and every user. Therefore here associate algorithm is proposed to attain this. Initial of all sub-channel allocation is pe...

The specifications of filter banks for multicarrier transmission systems with a large number of subchannels are discussed, with application to xDSL and power line communication in mind.The near PR modulated approach is considered and the importance, for the system, of the protype filter delay is stressed. An existing design technique known to be particularly relevant to the context is revisited...

Abstract. This paper presents the development and evaluation of a dynamic subchannel allocation scheme for downlink multi-cellular Orthogonal Frequency Division Multiple Access (OFDMA) systems. In the considered system each Access Point (AP) and the associated Mobile Terminals (MTs) are not operating on a frequency channel with a fixed bandwidth, rather the channel bandwidth for each AP is dyna...

Multicarrier code-division multiple-access is one of the effective techniques to gain its multiple access capability, robustness against fading, and to mitigate the ISI.In this paper, we propose an improved mulcarrier CDMA system with adaptive subchannel allocation. We analyzed the performance of our proposed system in frequency selective fading environment with narrowband interference existing...

When linear precoding is applied to filterbank multicarrier systems, a combination of all subcarriers is transmitted, minimizing the effect of a deep fade in a subcarrier while also reducing frequency offset sensibility and the peakto-average power ratio. However, their equalization becomes even more challenging than usual. In this paper, we present an analysis on the effect of multitap subchan...

This paper considers the problem of resource allocation for downlink part of an OFDM-based multi-cell cognitive radio network which consists of multiple secondary transmitters and receivers communicating simultaneously in the presence of multiple primary users. We present a new framework to maximize the total data throughput of secondary users by means of subchannel assignment, while ensuring i...

In this chapter, we focus on a cognitive wireless sensor network (WSN), where a primary WSN (PWSN) is co-located with a cognitive (or secondary) WSN (CWSN). The shared frequency spectrum can be “freely” assigned by the PWSN. In particular, this spectrum is divided into disjoint “subchannels” and each subchannel is assigned (in a unique way) to a node of the PWSN. We assume that the nodes of the...

We provide an architecture for future wireless information services as a collection of autonomous cells which o er information services of widely varying geographic scope. Each MSS (Mobile Support Station) has the freedom to decide how to allocate di erent information services to its bandwidth and in which form to o er them. Two basic forms of delivery of information service are identi ed : per...

This paper proposes a QoS-aware resource allocation scheme, called as cooperative resource allocation scheme (CoRA), for relay-based OFDMA systems with both QoS and Best-effort (BE) users. Using CoRA, cooperative transmission between the Base-station (BS) and the Relay-station (RS) is employed to fulfill the requirements of QoS users. Moreover, resource scheduling is allowed not only at the BS ...