The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In this paper, we introduce a full-duplex relay (FDR) based on block diagonalization (BD) and analyze the corresponding sum rate in a multiantenna multiuser relay system. The poposed precoding scheme can suppress the self-interference as well as to support multiple users at the same time slot. Simulation results show that the proposed FDR scheme enhances significantly the sum rate performance compared...
In this paper, we propose a novel interference alignment (IA) scheme via convex optimization based on minimum mean square error criterion subject to individual transmit power constraints for the MIMO interference channel system. We show that transceiver under such criterion can be realized through an efficient iterative algorithm. The convergence of the proposed algorithm is discussed. Simulation...
We propose an enhanced linear minimum mean square error (LMMSE) turbo equalization scheme for multiple-input multiple-output (MIMO) communication systems. The turbo equalizer employs soft interference cancellation (SIC), where tentative soft decisions of the interfering symbols are subtracted from the received samples before the LMMSE filtering. The enhanced LMMSE turbo equalization with SIC introduces...
This paper focuses on coordinated scheduling to combat uplink inter-cell interference for LTE/LTE-Advanced. In OFDM system, inter-cell interference is the dominant interference which limits system capacity, especially the performance of cell edge users. Meanwhile inter-cell interference in OFDM system has an inherent characteristic of interference fluctuation, which reduces the efficiency of channel...
Cognitive radios have been proposed as a solution to the spectrum underutilisation problem and have been proven to increase spectrum efficiency whilst providing opportunities for futuristic technologies. However, increased levels of interference are expected with the introduction of secondary spectrum access, therefore, proper interference management within the cognitive framework is imperative. The...
A new propagation model and software implementation combines the best of the NTIA-ITS Longley-Rice methodology and it's Irregular Terrain Methodology (ITM) software implementation, a set of deterministic approximation equations derived from the empirical data in ITU-R P.1546 and other ITU Recommendations, and Snell's Law and Beer's Law, to create the first truly point-to-point, terrain-specific international...
In the relay-enhanced cellular network, the target user will receive uncertain interference due to orthogonal transmission between BS and RS, which would make the traditional mechanisms of link adaptation and channel-aware scheduling invalid. In this paper, a novel resource scheduling scheme is proposed with a semi-static mode, in which dominant interferences for a target user are identified and inter-cell...
Thanks to silence suppression, the VoIP capacity can be improved. When the voice users are listening or thinking, the VoIP system does not need to allocate resources to them, thereby being able to accommodate more users. The main issue is how to immediately allocate resources to the user, when the user transits from the silence state to the talkspurt state. The IEEE 802.16e/m system provides two typical...
This paper provides detailed analysis and simulation for exploring the impact of out-of-band emissions (OOBE) from adjacent wireless cellular services to receive-only digital mobile radio services. Based on an extensive analysis of interference from vehicles with mobile cellular users in realistic roadway conditions, we propose proper methods for determining out-of-band emission spectral masks that...
This paper investigates the problem of uplink subcarrier and power allocation in a Cognitive Radio (CR) network that operates opportunistically within vacant licensed Primary Users (PUs)spectrum. The resource allocation algorithm aims to maximize the CR network throughput under PUs interference constraints. In this paper, CR interference introduced into PUs sub-bands is modeled as a composite of two...
Since a large number of femtocells may coexist in one macrocell area, interference management becomes a major issue in the deployment of femtocells, and therefore has been researched actively. In the IEEE 802.16m, one way to mitigate interference is Low Duty Operation (LDO) Mode for femtocells. Femtocell in the LDO mode changes alternately between available interval and unavailable interval. During...
This paper presents a study on interference caused by Secondary Users (SUs) due to miss-detection and its effects on the capacity-outage performance of the Primary User (PU) in a cognitive network for two scenarios of beacon transmitter placement: beacon transmitter located at PU transmitter or at PU receiver. Interference analysis shows that aggregate interference power from SUs has a Gamma distribution...
In this paper, we compare the capacities of WiFi networks in their different possible implementations. These implementations include hierarchical WiFi/WiMAX networks where WiFi APs are connected to the Internet using WiMAX links, and WiFi mesh networks where WiFi APs may play the role of routers that send packets to other APs, acting as Internet gateways. At the packet level, we model both WiFi and...
Using mutually shift orthogonal spreading codes, block spread code division multiple access (BS-CDMA) systems have been shown to achieve multiuser interference (MUI) free reception when signals of all the users arrive at the base station synchronously. In practice, imperfect synchronization destroys the orthogonality among users and causes MUI. We present in this paper the design of spreading and...
Unwanted feedback between the donor (receive) and coverage (service) antennas of a relay (repeater) are created by the radio echoes from the local scatters and direct path antenna isolation limitations. These radio echoes create interference not only in the incoming signal from the base station, but also cause instability in the repeater. In this paper, we present an interference cancellation system...
In a mobile relay system, the idle users can be formed as a cluster to support nearby active users. In order to reduce the complexity of the processing in the relay nodes and destination nodes, a novel transmit preprocessing method is proposed for the cluster based multi-user relay system. Block diagonalization (BD) algorithm is adopted twice in the proposed method to remove inter-cluster and intra-cluster...
Abstract - A new inter-cell interference aware channel estimation technique for OFDM systems is presented. In the proposed algorithm, user equipment (UE) jointly detects the channel weights of the communication links associated with the serving and the interfering cells. Performance benefits of the proposed method are demonstrated by considering the OFDMA downlink as defined in 3GPP Long Term Evolution...
The goal of our work is to limit in-band inter-cell interference in wireless communication cellular systems. Based on interference classification techniques, we propose a novel centralized inter-cell power allocation algorithm which computes the minimum power budget required in each cell to meet its local quality of service (QoS) constraints. Both analytical and numerical results applied to cellular...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.