Video streaming is becoming increasingly popular among the wireless users. However, supporting video streaming over the wireless networks is not an easy task due to the dynamic radio propagation environment, limited radio resources as well as Quality of Service (QoS) requirements of the video streaming that need to be satisfied at acceptable levels. Most studies proposed to support video stream...

This paper presents a pilot-aided channel estimation method which is particularly suitable for mobile WiMAX 802.16e Downlink Partial Usage of Subchannel mode. Based on this mode, several commonly used channel estimation methods are studied and the method of least squares line fitting is proposed. As data of users are distributed onto permuted clusters of subcarriers in the transmitted OFDMA sym...

A system based on orthogonal frequency division multiple access (OFDMA) has been developed to deliver mobile broadband data service at data rates comparable to those of wired services, such as DSL and cable modems. We consider the resource allocation problem of assigning a set of subcarriers and determining the number of bits to be transmitted for each subcarrier in OFDMA systems. We compare si...

In this letter, we propose an efficient scheme for combining scheduling and channel allocation functions in multi-channel systems such as an orthogonal frequency division multiple access (OFDMA). In our approach, the scheduling function is embedded in the channel allocation function in an implicit manner, and the implicit scheduler only translates quality-of-service (QoS) requirements into a se...

Escalating demand of higher data rate in progressive generations for wireless environment involve work towards modification of modulation schemes over air interface. Beginning from TDMA/FDMA/CDMA based 2nd generation to highly complicated Orthogonal FDMA (OFDMA), Single Carrier FDMA (SC-FDMA), Interleaved FDMA (IFDMA) and Multicarrier CDMA (MC-CDMA) which are gaining attention for 4G networks. ...

OFDM is a broadband wireless technology which supports data rates in excess of 100 Mbps. In addition to this, OFDM has some limitations as it requires strict frequency synchronization and low peak to average power ratio. So considering DFT-OFDMA, which performance in terms of PAPR, is equivalent to SC-FDMA. This paper represents the suitability of using OFDMA in the up-link for high-data-rate s...

In this paper, we study the complexity and approximability of the orthogonal frequency-division multiple access (OFDMA) scheduling problem with uniformly related communication channels. Our modelling approach for this problem follows numerous studies from the engineering sciences that are mostly concerned with the performance of heuristics for different variants of the problem. One is given n ≥...

In this paper, two different dynamic cell coordination stratagies for frequency selective and flat fading are proposed for efficient subcarrier allocation in the joint consideration of adaptive modulation and variable frequency reuse in the channel-aware OFDMA downlink multicellular environment. Compared to a conventional OFDMA system without cell coordination, where system throughput may becom...

WiMax(World Wide Interoperability for Microwave Access) provides high data rate over long distance wireless communication .Generally Wimax adapted OFDM (Orthogonal code division multiple access) architecture as transmission medium in IEEE 802.16 standard. Our aim is to analysis MC-CDMA (Multicarrier code division multiple access) based WiMax design and verify the performance under different mod...

In this paper, we propose a new heuristic for a Bi-Allocation uplink problem when using OFDMA multiuser wireless systems. This is done by assuming a new detection scheme of “two” or fewer incoming signals from different users to each receiving detector subcarrier of the base station which is based on product trellises. A gain of 13.56% in (bits/s/Hz) is achieved in capacity bandwith channel by ...