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We investigate the maximum outage throughput for Orthogonal Frequency Division Multiple Access (OFDMA) systems in the presence of feedback channel capacity constraints. We attempt to establish an information-theoretic lower bound on the capacity of feedback channel and build the corresponding test channel that achieves this lower bound. Based on the derived test channel, we formulate the outage throughput...
In this paper, we propose a novel scheme that joints two-level spreading OFDM and beam forming. For further interference suppression, we assign a proper spreading code at transmitter and employ the Minimum Mean Square Error - MUltiuser Detection (MMSE-MUD) equalizer at receiver. Simulation results show that the proposed system outperforms the conventional two-level spreading OFDM system under multipath...
In this paper, we propose a multicarrier system for anti-jamming communications. This system employs two sets of spreading codes to spread the signal in both time and frequency domain, while it can use the same bandwidth as the MC-CDMA system. We derive its error probability under multipath fading channels with jammers. Simulation results show that this system is more robust against narrowband partial-time...
Orthogonal frequency division multiple (OFDM) system with two-level spreading is an effective approach to suppress interference in wireless communication. However, in this system, the orthogonality of its spreading code can be destroyed by multipath fading. In this paper, we propose a novel resource allocation scheme that joints conventional two-level spreading OFDM and smart antenna so as to use...
We propose a resource allocation algorithm for OFDM system to provide QoS guarantee for unicast and multicast service concurrently. The optimization objective is to maximize the sum rate of the unicast service under the constraint of both the total power and the minimal rate provision of the multicast service, which can be solved by traditional two-step approach. To decrease the complexity, a greedy-based...
In this paper, we propose a predictive resource allocation algorithm for multicast downlink OFDM systems with imperfect channel state information (CSI). We assume that the CSI is fed back to the base station (BS) through a delayed channel. To avoid the system degradation caused by the outdated CSI, we present a channel prediction scheme at the user side, which takes the delay time into account. Then,...
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