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.
With the advent of new applications, one of the primary applications supported in downlink cellular systems is streaming video. QoS for streaming video entails data transmission to the mobile stations with limited latency and limited jitter. This requirement on latency and jitter can be mapped to the number of yet-to-be-played packets in a mobile station's buffer, to always be above a certain minimum...
This paper reformulates the multi-user OFDMA resource allocation problems in broadcast and multiple-access channels by defining an equivalent interference channel. The resulting problems are then solved by employing low-complexity algorithms for spectrum optimization in the interference channel. The re-formulation averts the high-complexity integer programming problem that otherwise results from an...
This paper defines a new metric: a relay gain that measures the performance gain of users using relaying channels at distance s from a base station. The paper derives the closed form of the relay gain for urban macro-cells and rural areas, and shows that the closed form provides much information about how to maximize the performance gain of relay systems. Further, this paper investigates the fairness...
This paper considers the subchannel-allocation problem to maximize the sum-rate in orthogonal frequency- division multiple-access (OFDMA) regenerative relaying downlink systems with a total power constraint. Based on the Lagrange dual decomposition and the optimal condition of the problem, this paper proposes three heuristic algorithms: an extended modified inverse subchannel signal-to-noise ratio...
This paper develops the optimal power-allocation algorithm to maximize the sum-rate in orthogonal frequency-division multiple-access (OFDMA) regenerative relaying downlink systems with separate power constraints. The optimal algorithm is based on the Lagrange dual-decomposition method when subchannels are pre-assigned to users and relay stations (RS). This paper also proposes a heuristic algorithm,...
This paper proposes efficient rate and power allocation algorithms for OFDMA downlink systems where each tone is taken by at most one user. Weighted sum rate maximization (WSRmax) and weighted sum power minimization (WSPmin) problems are considered. Since these resource allocation problems are non-convex, complexity of finding the optimal solutions is prohibitively high. This paper employs the Lagrange...
This paper investigates the effect of non-zero SNR margin and coding gap on the maximum sum rate and achievable rate region of the Gaussian multiple-access channel (MAC). Frequency-division multiple-access (FDMA) is shown to be the only sum-rate-maximizing scheme for a scalar Gaussian MAC when the margin/gap is not zero. Furthermore, successive decoding is shown to be strictly sub-optimal from a sum...
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.