1 good. The conventional handover scheme is performed considering only downlink information. However uplink and downlink signal qualities can be asymmetric in Time Division Duplexing (TDD)/Orthogonal Frequency Division Multiple Access (OFDMA) systems like IEEE 802.16e systems. Therefore conventional handover schemes based on the downlink signal could degrade the uplink quality of service (QoS)....

Using relays to receive and forward packets between a network base station and network users is a promising solution to address the cellular coverage issue. In this paper, we consider time division duplexing (TDD) networks and explore the use of network coding for implementing the relays. Several transmission scenarios are investigated, including direction transmissions, one-way relay and two-w...

It has been observed that concentrated solutions of short DNA oligomers develop liquid crystal ordering as the result of a hierarchically structured supramolecular self-assembly. In mixtures of oligomers with various degree of complementarity, liquid crystal microdomains are formed via the selective aggregation of those oligomers that have a sufficient degree of duplexing and propensity for phy...

This paper presents an overview of the wideband CDMA concept which was chosen in ETSI (European Telecommunications Standards Institute) in January 1998 as a basis for UMTS air interface for FDD (Frequency division duplexing) operation. UMTS is the 3rd generation mobile communication system specified within ETSI. This paper is organized as follows. First, the background of WCDMA is presented in ...

In this paper, the switched beam antenna array is analyzed and its model in the system level is presented firstly. Based on the combination of multi-user detection (MUD) and the switched beam antenna (SBA) techniques in the time division duplexing-code division multiplex access (TDD-CDMA) system, the uplink load is investigated and the corresponding advanced uplink admission control scheme base...

Array antennas have the potential to increase the capacity of wireless networks, but a distributed beamforming algorithm for maximizing the capacity in asynchronous, decentralized mobile ad hoc networks is yet to be found. In this paper we pursue an interference avoidance policy, based upon channel reciprocity in time-division duplexing, and arrive at a practical signaling technique for array a...

We introduce novel blind and semi-blind channel estimation methods for cellular time-division duplexing systems with a large number of antennas at each base station. The methods are based on the maximum a-posteriori principle given a prior for the distribution of the channel vectors and the received signals from the uplink training and data phases. Contrary to the state-of-the-art massive MIMO ...

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 ...

This paper proposes a new antenna array calibration technique which uses frequency selection in orthogonal frequency division multiple access (OFDMA)/time division duplexing (TDD) systems. In the proposed method, subbands or frequencies of good channel conditions are initially selected for channel measurements. The relative calibration is performed at the selected subbands, which compensates fo...

Coexistence of different access technologies, hierarchical cellular deployment, a wide variety of data services, requirements for transparent operation across different technologies, adaptivity to varying network conditions and mobility and quality of service (QoS) constraints introduce a number of challenges in the design of future generation systems and the specification of new air interfaces...