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Wireless mesh network (WMN) is a promising technology for broadband Internet access due to its low cost, ease of deployment, increased coverage, and robustness. Equipping each mesh router with multiple radios can greatly improve the capacity of WMNs since the radios at each node can simultaneously transmit data on orthogonal channels. Channel assignment is an important problem in multi-radio multi-channel...
This paper presents performance comparison of register allocation algorithms in DBT (dynamic binary translation). A group of register allocation algorithms including SRA (simple register allocation), GRA (global register allocation), NRA (next-use register allocation) and SGRA (simplified graph-coloring register allocation) are implemented in a DBT system and evaluated. SGRA is a simplified version...
In this paper, a distributed power control algorithm is proposed to perform adaptive spatial multiplexing for the relay enhanced orthogonal frequency division multiple access (OFDMA) cellular systems. As the optimal spatial multiplexing problem is non-convex, we utilize the distributed iteration method to achieve its near-optimal solution. By determining the restriction on the transmit power for each...
3GPP LTE specification is stable now in release 8. To meet much higher requirements than release 8, 3GPP has initiated the LTE-A (LTE-Advanced) study item. In LTE-A, CoMP (coordinated multiple point transmission and reception) and CA (carrier aggregation) are two new features. CoMP is used to improve coverage and to increase cell-edge throughput. It is considered as an effective approach for ICIC...
In this paper, we propose orthogonal frequency division duplex (OFDD) which combines orthogonal division duplex (ODD) and frequency division duplex (FDD) as a new hybrid division duplex scheme. In the asymmetric traffic environment, the mismatch of uplink and downlink between adjacent cells results in co-channel interference (CCI) which degrades the system performance. The proposed scheme can remove...
Conflict-free power allocation for secondary user (SU) in cognitive networks is a challenging problem since the accessible spectrum of the SU is shared with the primary user (PU); the problem becomes to be especially difficult when it is wanted to achieve the maximum network capacity considering the mutual interference between PU and SU. In this paper, specifying the single SU case with multiple PUs,...
In this paper, a binary power allocation scheme is proposed for dense cognitive networks with plentiful secondary nodes. During the power allocation, the capacity loss of the primary system is controlled to be lower than a predefined level; and the capacity of the secondary system is ensured to some extent. Most importantly, based on the theoretical derivations, the power allocation is proved to be...
In this paper, we propose an efficient power allocation scheme that aims at maximizing the system throughput in joint spectrum overlay and underlay cognitive radio network. We show that our proposed scheme enlarges the achievable throughput region comparing to the overlay strategy, and causes less interference than the underlay strategy. In addition, since the unlicensed users adopting the overlay...
Computing capacity bounds of ad hoc networks, as well as optimizing radio resource allocation in order to approach those bounds is a hard task that have recently attracted the interest of the research community. In this paper we address the problem of jointly optimizing the routing of flows, the transmission scheduling over wireless links along the path, and the emitted power for bandwidth guaranteed...
There is a great surge of interest recently in the fixed-mobile convergence from the telecom industry. This is supported by strong 3G operator interest in using the broadband penetration as a spring board to achieve cost effective delivery of the multimedia data for indoor coverage. Statistics indicated that more than 70% of the calls are made from end-users in indoor environments. Based on this trend,...
To settle the contradiction between scarce radio spectrum resource and the exigent requirement, effective methods of dynamic spectrum allocation are proposed in cognitive radio system. In this paper, game theory model and graph-coloring model are analyzed, which can improve spectrum efficiency and solve the deficiency of spectrum resource.
Shared cache allocation policies play an important role in determining CMP performance. The simplest policy, LRU, allocates cache implicitly as a consequence of its replacement decisions. But under high cache interference, LRU performs poorly because some memory-intensive threads, or aggressor threads, allocate cache that could be more gainfully used by other (less memory-intensive) threads. Techniques...
In OFDMA systems, reducing the inter-cell interference among adjacent cells is a very important issue especially for the cell-edge users. In this paper, we propose a distributed algorithm that maximizing the system total throughput considering proportional fairness. In our proposed algorithm, the frequency resources in each cell is divided into high and low power regions. The bandwidth allocations...
This paper proposes a novel semi-dynamic inter-cell interference coordination (ICIC) scheme for multi-cell OFDMA systems. The objective of the novel scheme is to strike a balance between ICI minimization and frequency reuse factor (FRF) maximization. Firstly, we divide cell-edge users into non-overlapping user groups based on users' geometry, and classify each group's available bandwidth, which includes...
We introduce the problem of joint routing, scheduling and power control for multiple information flows in half-duplex, interference limited ad-hoc networks. The joint problem of optimizing for throughput is NP-Hard, and so we present an approximation of the problem and a general framework for solving it in O(N3) time. We attack the problem in two ways, first by presenting a reformulation and decomposition...
It is widely recognized that current policies for allocating wireless spectrum have led to inefficiencies and under-utilization. One proposed solution to this is to enable "spectrum markets", which allow for entities to sell and/or lease spectrum dynamically over time. In this paper we consider the design of such a market and how this is influenced by the underlying properties of the wireless...
This paper investigates the properties of social choice functions, that represent resource allocation strategies in interference coupled wireless systems. The resources can be physical layer parameters such as power vectors or antenna weights. The paper investigates the permissible social choice functions, which can be implemented by a mechanism in either Nash equilibria or dominant strategy - for...
Uncoordinated deployment of eNBs in local area environments will benefit from having support for dynamic frequency re-use mechanisms also known as "autonomous component carrier selection", where each eNB dynamically selects to use only a subset of the available component carriers (i.e. using from one component carrier up to the maximum number of available component carriers). Component carriers...
A compound instruction, encoding several ALU or memory operations within an instruction word, has been regarded as an efficient way of improving performance. In the compiler for embedded processors, the code generation algorithm for compound instructions has been built by dealing mainly with instruction selection which is a crucial phase of code generation. In this paper, we propose an iterative code...
Embedded systems often require small code size due to their tight memory constraints. Although the reduced encoding architectures such as the ARM THUMB or the MIPS-16 can successfully reduce the code size due to its half-sized instructions, they suffer from higher spills due to their shortened register fields which constrain available registers, thus affecting the code size and the performance negatively...
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