“…Up to now, freedoms F1, F3, F4 and F6 were partly examined in [9,[147][148][149][150], and freedom F5 was mentioned in [45,46]. Freedom F2 remains unexplored, and there are many options for freedom F3.…”
Section: Discussionmentioning
confidence: 99%
“…For the integral in (5.8), applying the Schwarz inequality yields 9) where the equality holds if and only if…”
Section: Optimal Beamformingmentioning
confidence: 99%
“…In [279], the upper bounds on the ergodic and outage capacities of two-hop UWB relay networks were given based on the approach developed in [55], where the frequency selectivity of the considered UWB channels was treated by equivalent multiple parallel channels, similar to the orthogonal frequency-division multiplexing (OFDM) approach. In [9], UWB nodes which are neither the source node nor the destination node are treated as relay nodes opportunistically. Then several STC schemes based on cyclic division algebras are proposed to improve the performance of the overall system.…”
Section: Introductionmentioning
confidence: 99%
“…Then several STC schemes based on cyclic division algebras are proposed to improve the performance of the overall system. Note that each node considered in [9] is equipped with only a single antenna, while the 'space' refers to the multiple antennas across multiple nodes, including both the source and relay nodes. In [147,149], a multi-antenna relaying scheme is proposed, where multiple antennas are mounted at the relay node to increase the reliability of the relay by making use of the spatial diversity of the channels.…”
“…Up to now, freedoms F1, F3, F4 and F6 were partly examined in [9,[147][148][149][150], and freedom F5 was mentioned in [45,46]. Freedom F2 remains unexplored, and there are many options for freedom F3.…”
Section: Discussionmentioning
confidence: 99%
“…For the integral in (5.8), applying the Schwarz inequality yields 9) where the equality holds if and only if…”
Section: Optimal Beamformingmentioning
confidence: 99%
“…In [279], the upper bounds on the ergodic and outage capacities of two-hop UWB relay networks were given based on the approach developed in [55], where the frequency selectivity of the considered UWB channels was treated by equivalent multiple parallel channels, similar to the orthogonal frequency-division multiplexing (OFDM) approach. In [9], UWB nodes which are neither the source node nor the destination node are treated as relay nodes opportunistically. Then several STC schemes based on cyclic division algebras are proposed to improve the performance of the overall system.…”
Section: Introductionmentioning
confidence: 99%
“…Then several STC schemes based on cyclic division algebras are proposed to improve the performance of the overall system. Note that each node considered in [9] is equipped with only a single antenna, while the 'space' refers to the multiple antennas across multiple nodes, including both the source and relay nodes. In [147,149], a multi-antenna relaying scheme is proposed, where multiple antennas are mounted at the relay node to increase the reliability of the relay by making use of the spatial diversity of the channels.…”
“…Cooperative diversity was extended to the context of UWB systems in [10] - [13]. Employing DF and AF protocols, the authors in [10,11] present the construction of space-time (ST) codes suitable for IR-UWB. In [13], the authors analyzed the bit error probability of time hopping UWB relay networks under IEEE 802.15.4a channel models.…”
Abstract. Inter-vehicle communication (IVC) have lately attracted a great interest in commercial and military fields to develop applications that can make transportation safer and more efficient. Ultra wideband (UWB) technology is a candidate as a license-free radio link for intervehicular transmission. Reliable data transmission between vehicles is difficult to accomplish due to the presence of noise and obstacles. The objective of this paper is to outline the effectiveness of cooperative transmission in vehicular network using impulse radio ultra wideband (IR-UWB) transmission. We consider a relay network applying decode-and-forward (DF) protocol and evaluate the bit error rate (BER) performance of direct sequence binary phase shift keying (DS-BPSK). Multiple access capability is set up using direct sequence spreading codes (DSSS) and we analyze the effect of multiple access interference (MAI). Our results demonstrate the diversity gains and BER performance improvement in two scenarios; perfect and imperfect source-relay channels.
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