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We study a cooperative non-orthogonal multiple-access (NOMA) system with buffer-aided relaying. By assuming that the relay node possesses a buffer, we propose an adaptive transmission scheme in which the system adaptively chooses its working mode in each time slot. The optimal mode selection scheme that maximizes the sum throughput of the NOMA users is obtained. Numerical results validate our analysis...
In this paper, a distributed mobile relay power control (DMRPC) scheme for maximizing individual cell throughput is proposed for mobile relay station (MRS) aided system. In the system with DMRPC, the power levels of MRSs are controlled by individual cell without cell cooperation and signaling overhead, and the appropriate power levels of MRSs are selected to maximize the cell throughput of their individual...
In this paper, we present a cooperative MAC protocol called automatic relay cooperative MAC (ARC-MAC) for wireless Ad Hoc networks. ARC-MAC develops the 802.11 DCF to five handshakes, which is suitable for cooperative transmission. According to the channel condition, neighbors decide whether it is a relay by itself, and the relay helps the source transmitting packets with a definite probability. An...
This paper proposes a cooperative multiple access protocol based on the distributed coordination function (DCF) request-to-send/clear-to-send (RTS/CTS) scheme for distributed wireless networks. It answers three key questions concerning cooperation from the network perspective, namely when to cooperate, whom to cooperate with and how to protect cooperative transmissions. According to our protocol,...
Uplink users in cellular networks, such as UMTS/HSPA, located at the edge of the cell generally suffer from poor channel conditions. Deploying intermediate relay nodes is seen as a promising approach towards extending cell coverage and increasing data rates. This paper focuses on the role of packet scheduling in cellular networks with relay nodes. In particular, two uplink scheduling schemes deploying...
Cooperative hybrid-ARQ (HARQ) protocols have been widely studied because they are more efficient than cooperative protocols without HARQ. In, the throughput of a cooperative HARQ protocol based on the decode-and-forward protocol (DF-HARQ) is obtained. In this paper, the maximum achievable throughput of the DF-HARQ protocol is obtained using the asymptotic outage probability when the maximum number...
The problem of anonymous wireless networking is considered when adversaries who monitor the transmissions in the network are also capable of compromising a fraction of nodes to extract network information. For a given level of network performance, as measured by network throughput, the problem of maximizing anonymity is studied from a game-theoretic perspective. The metric of anonymity considered...
A cognitive OFDM-based relay network is considered in this paper. Communication between any node pair occurs on a spectrum pool of OFDM subcarriers where the subcarriers are not used by primary users. Therefore, the available spectrum for different transmitter-receiver pairs is distinct due to their location difference and so on. To satisfy different traffic demand and improve system performance,...
IEEE 802.15.4 was developed to meet the needs for simple, low-power and low-cost wireless communication. In the past couple of years it has become a popular technology for wireless sensor network. But in practical projects, we find that a long association delay is a critical problem in some real-time applications. This paper proposes a new association scheme named fast association mechanism (FAM)...
For maximizing the benefit of network coding in two-way relay networks, the data rate of links from sources to a relay should be the same, since only the same number of received bits can be network-coded at a given time and the rate for broadcast at the relay is limited by the minimum rate over all links. Therefore, we investigate rate control scheme based on power control to maintain the link to...
In this paper, a novel relay selection scheme is proposed for the wireless network with multiple half-duplex relay nodes, which improves relay throughput by selecting more than one relay nodes in each relay-help transmission and using the selection of active relay nodes to map a portion of information to be relayed. Compared with the existing relay selection scheme with only one active relay node...
Relays are being proposed as key technology elements for LTE-Advanced (LTE-A). This paper shows that throughput gains of using relays in a cellular network (relative to a network without relays) are highly dependent on relay coverage which is defined as the percentage of users served by relays. System-level simulations and analysis is used to illustrate the impact of relay coverage on throughput performance...
User cooperation enables single antenna terminals to benefit from spatial diversity by partnering with other users to create a virtual transmit antenna array. A promising form of cooperation is called coded cooperation which integrates cooperation with channel coding, showing great performance gains. In this paper, we examine the performance of coded cooperation scheme in fixed relay system, where...
Relaying is one of the most important novel elements in 3GPP LTE-Advanced study item. It promises to offer significant gain for system capacity or coverage depending on the deployment prioritization. In this paper, we investigate the feasibility of relay node deployments in terms of system throughput and cell coverage area extension as compared to pico node deployments and traditional homogeneous...
The achievable transmission rate of the multicast services is in general limited by the worst case mobile users within the multicast service sectors. Yet, unlike relay-assisted unicast service, there is a unique challenge in applying relay to multicast service. To be more specific, the multicast service shall be able to provide a uniform treatment for the mobile users within and without the relay...
An adaptive resource allocation scheme is proposed for regenerative relay-based orthogonal frequency division multiplexing access systems. This scheme allocates subchannels to guarantee fairness between users, and also saves energy by minimising the transmission power. The subchannel allocation for data rate fairness is considered between direct link users and relay stations in the first time subslot...
In the IEEE 802.16j multi-hop relay (MR) network, the design of an effective path selection scheme is an important issue for throughput gain and overhead reduction. This paper proposes a new metric, called SEL, to evaluate the possible relay paths and thereby determine the appropriate one among these paths. SEL mainly considers both link spectral efficiency and link load, and based on SEL, a comprising...
In this paper, we consider a three-node relay system with a hybrid relaying scheme, where the relay, based on its decoding status, switches between decode-and-forward (DF) and compress-and-forward (CF) adaptively. We propose according HARQ strategy and analyze its throughput performance. Then, we consider practical implementation issues by enhancing the ability of the feedback channel from the destination...
Opportunistic scheduling and rate-adaptation mechanisms exploit the variations in the channel states experienced by different users through the allocation of resources to users with better channel quality. Opportunistic scheduling has been considered in various contexts, typically with the assumption that rate adaptation and channel reassignment can be implemented with no delay, based on the instantaneous...
We study the impact of user cooperation in wireless networks on improving the stable throughput and delay performance. Specifically, we consider a multiaccess system in which a set of source users generate packets to deliver to a common destination. A cooperation strategy is proposed at the protocol level, where users with a better channel to the destination have the option to relay packets from users...
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