In this paper, two candidates for a next generation (4G) downlink system in a multi−cell environment are studied in respect to their error performance. We investigate on the one hand, an orthogonal frequency division multiplexing (OFDM) based multiple access scheme (OFDMA), and on the other hand, a multi−carrier code division multiple access (MC−CDMA) scheme. The studies of both transmission sc...

In this paper, a novel sub-channel based uplink Orthogonal Frequency Domain Multiple Access (OFDMA) random access scheme is proposed. In the next generation Wireless Local Area Network (WLAN), OFDMA was adopted in order to enhance throughput performance. OFDMA can be used for both downlink and uplink. In order to utilize OFDMA for uplink, AP needs to schedule stations’ packet transmission. In o...

The transfer of data from multiple internet things (IoT) devices requires the use a robust and efficient access (MA) solution. This paper considers orthogonal frequency division MA (OFDMA) technique for light-fidelity (LiFi)-based IoT uplink using infrared to transmit mobile users fixed point. conventional schemes based on allocate distinct subcarriers each user sharing same time slot. We consi...

11:45 – 13:15 S1 OFDMA Systems I 1 Rate Adaptive Resource Allocation with Fairness Control for OFDMA Networks Emanuel B. Rodrigues (Universitat Politècnica de Catalunya, Spain); Ferran Casadevall (Universitat Politècnica de Catalunya, Spain) 2 Downlink Rate-Guaranteed Scheduling for Multiuser OFDMA Cellular Systems Jerzy Martyna (Jagiellonian University, Faculty of Mathematics and Computer Scie...

OFDMA is considered as one of the major candidates for broadband wireless access. The OFDMA signal is usually coherently demodulated, requiring the channel estimation which can be estimated using a known pilot signal. In multicell environment, the performance of channel estimation is mainly limited by intercell interference. It is desirable to use a pilot signal that can estimate the channel in...

In the growth of fourth-generation mobile servicing, long` c ns term evolution (LTE) is an emanate technology. In LTE the downlink model build up on orthogonal frequency division multiple access (OFDMA) and the uplink arrangement build up on single carrier frequency division multiple access (SC-FDMA).In this paper we have tendency to derive the achievement of typical elemental differences betwe...

Orthogonal Frequency-Division Multiple Access (OFDMA) is a multi-user version of the Orthogonal frequency-division multiplexing (OFDM). OFDMA is used in the mobility mode of IEEE 802.16 WirelessMAN Air Interface standard, commonly referred to as WiMAX. Multiple access is achieved in OFDMA by assigning subsets of subcarriers to individual users [1], [2]. The performance of these systems depend o...

Long Term Evolution (LTE) is consents pliable spectrum distribution which renders enriched wireless data services to users at lower latency and multi-megabit throughput. LTE uses Orthogonal Frequency Division Multiple Access (OFDMA) and Single Carrier Frequency Division Multiple Access (Sc-FDMA) for downlink and Uplink transmission where OFDMA has been acquired in LTE for downlink transmission ...

Worldwide interoperability for Microwave Access (WiMAX) is a Broad Band Wireless Access (BWA) technology. It provides high data rates and multimedia services. It also supports Quality of Services (QoS) for various types of application. When large number of users use these application, the OFDMA is used to divide the channel into several subchannels and those subchannel can be provided for diffe...

Orthogonal Frequency-Division Multiple Access (OFDMA) systems have attracted considerable attention through technologies such as 3GPP Long Term Evolution (LTE) and Worldwide Interoperability for Microwave Access (WiMAX). OFDMA is a flexible multiple-access technique that can accommodate many users with widely varying applications, data rates, and Quality of Service (QoS) requirements. OFDMA has...