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The long term evolution (LTE) system employs orthogonal frequency division multiple access (OFDMA) and single carrier frequency division multiple access (SC-FDMA) for the downlink and uplink transmission, respectively. However, in most existing literatures regarding the two-way OFDMA resource allocation, all terminals are assumed under an OFDMA operation, and the allocation scheme is always considered...
Recently, the concept of the cooperative communications has been applied extensively for the ultra-wideband (UWB) system. In this paper, the cooperative scheme of the noncoherent UWB impulse radio system with block-coded modulation (BCM) having a codeword matching and signal aggregation (CMSA) detection is discussed under different fading environments, which has not been studied yet. To enlarge the...
The amplify-and-forward protocol is a simple but effective relaying for cooperative communications systems because its associated relay node does not take encoding/decoding into consideration to re-transmit signals. However, the interference and multipath fades during the previous hop are also amplified. In this paper, based on the zero-forcing (ZF) concept, an adaptive amplification factor is investigated...
To overcome the limitation of the transmit power spectral density, the cooperative communication in the ultra-wideband (UWB) differential transmitted reference system is studied. The amplify-and-forward is used as a relay protocol to re-transmit signals from multi-source terminals to one destination terminal. An adaptive amplification factor based on the channel information between relay and destination...
The conventional amplify-and-forward relaying protocol has less complex but worse performance than the decode-and-forward type. In the orthogonal frequency division multiplexing (OFDM) multihop relay systems, the system capacity can be enhanced via using the subcarrier permutation scheme at the relay terminals. However, under the multiuser scenario, one subcarrier may possess the best condition for...
Under the impact of multiuser interference, the exact bit error probability of the time-hopping ultra-wideband differential transmitted reference system over the Nakagami-m fading channels is evaluated via applying the characteristic function (CF) method. The CF method does not introduce any unrealistic assumptions, therefore our numerical results from the CF method demonstrate a better match in comparison...
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