We proposed a 60 GHz multiband-orthogonal frequency-division-multiplexing (MB-OFDM) system using millimeter-wave (MMW) photonic techniques. A simple optical modulation scheme is developed to generate 60 GHz carrier by...
详细信息
We proposed a 60 GHz multiband-orthogonal frequency-division-multiplexing (MB-OFDM) system using millimeter-wave (MMW) photonic techniques. A simple optical modulation scheme is developed to generate 60 GHz carrier by the sixth-harmonic term of local oscillator (LO) frequency. We have experimentally demonstrated that the wireless MMW photonic MB-OFDM system can transmit data at up to the rate of 480 Mbps and the maximum wireless-transmission distance can reach 3 m.
the opportunistic relaying scheme withthe selection of antennas at source and destination is the best option,to eliminate the insufficient use of the channel resources and low- cost low-complexity alternative to capt...
详细信息
the opportunistic relaying scheme withthe selection of antennas at source and destination is the best option,to eliminate the insufficient use of the channel resources and low- cost low-complexity alternative to capture many of the advantages of MIMO (multiple input,multiple output) systems [1][4].In such a scheme,the best relay as well as best antennas at source and destination can be selected for *** this paper,we will introduce the opportunistic amplify and forward relaying scheme without direct link using antennas selection at source and destination *** assumption of independent and not necessarily identical Rayleigh fading channel,in this proposed scheme the exact outage probability performance will be analyzed and observed that the antenna selection provides a good tradeoff between cost,complexity,and *** the other hand,best relay selection scheme has a strong advantage in saving the channel resources compared to regular cooperative diversity networks.
Optical orthogonal codes (OOCs) have been studied by many researchers to increase its flexibility such as variable code length and variable code weight. Recently, the authors have proposed OOCs with variable chip rate...
详细信息
Optical orthogonal codes (OOCs) have been studied by many researchers to increase its flexibility such as variable code length and variable code weight. Recently, the authors have proposed OOCs with variable chip rates (VC-OOC), which can keep the orthogonal property of the strict OOC even when different chip rate codes are used in an optical CDMA network for signal multiplexing. In this paper, the VC-OOCs are reviewed and some approaches of code design using the balanced incomplete block design (BIBD) sequences are proposed. the BIBD parameters suitable for the variable chip rate codes are obtained and discussed.
In mobile ad hoc network （MANET）,mobile nodes should use the other nodes and trust them for transmitting *** to lack of central control,an intermediate node may drop the data packets because of being selfish or *** ...
详细信息
ISBN:
(纸本)9781467321006
In mobile ad hoc network （MANET）,mobile nodes should use the other nodes and trust them for transmitting *** to lack of central control,an intermediate node may drop the data packets because of being selfish or *** this paper,the problem of routing misbehavior is *** new acknowledgement-based scheme,called NEWACK,is introduced based on the DSR *** method for detecting the collusion attacks （cooperating between malicious nodes）,is *** results are presented to evaluate the performance of the proposed scheme and compare it withthe other methods.
While a considerable effort is devoted to analysis and optimization of energy efficiency of both wired and wireless broadband access networks, power consumption of devices attached to the network by the end-user is us...
详细信息
ISBN:
(纸本)9781467322287
While a considerable effort is devoted to analysis and optimization of energy efficiency of both wired and wireless broadband access networks, power consumption of devices attached to the network by the end-user is usually neglected. Faster net access motivates the subscriber to buy and intensively use additional power-hungry devices, e.g. large-screen TVs. Relatively simple calculations shows this contribution to be substantial, creating additional burden on power systems and environment. An analysis made for the case of universal introduction of fiber access in Poland shows the required investment in extra power generation capacity will be comparable with cost of nationwide FTth network. For its subscribers, increase in electricity bills may compete with fees for broadband access.
We proposed a new 60 GHz multiband-orthogonal frequency-division-multiplexing (MB-OFDM) radio-over-fiber (ROF) system using millimeter-wave (MMW) photonic techniques. A simple optical modulation scheme is developed to...
详细信息
We proposed a new 60 GHz multiband-orthogonal frequency-division-multiplexing (MB-OFDM) radio-over-fiber (ROF) system using millimeter-wave (MMW) photonic techniques. A simple optical modulation scheme is developed to generate 60 GHz carrier by the sixth-harmonic term of local oscillator (LO) frequency. Moreover, the experimental setup of proposed system to demonstrate that the wireless MMW photonic MB-OFDM system can transmit data at up to the rate of 480 Mbps and the maximum wireless-transmission distance can reach 3 m.
Since querying trees in wireless sensor networks are normally built in an ad-hoc manner, equal workload among sensors cannot be guaranteed. A sensor with more descendants has to relay more data that cause its energy e...
详细信息
Since querying trees in wireless sensor networks are normally built in an ad-hoc manner, equal workload among sensors cannot be guaranteed. A sensor with more descendants has to relay more data that cause its energy exhausted more quickly. To prolong the lifetime of such a sensor and its network we propose an adaptive balancing workload protocol consisting of two phases. First, it builds a balanced-query tree that allows nodes close to a sink to share their workload. Second, it adaptively switches the workload from an exhausted node to non-exhausted nodes. the simulation was carried out to validate the proposed protocol and compare it with previous work. the simulation shows that after running 2,100 rounds, the node by our proposed scheme still remains 20% of initial energy while the one by previous schemes runs out of energy fully exhausted.
Simulations have been performed to compare the link power budget and power dissipation of carrierless amplitude and phase modulation-64 (CAP-64) and 64-quadrature amplitude modulation-orthogonal frequency division mul...
详细信息
Simulations have been performed to compare the link power budget and power dissipation of carrierless amplitude and phase modulation-64 (CAP-64) and 64-quadrature amplitude modulation-orthogonal frequency division multiplexing (64-QAM-OFDM) systems over feedforward error correction (FEC) enhanced plastic optical fibre (POF) links using light emitting diodes (LEDs). It is shown that CAP-64 outperforms 64-QAM-OFDM and supports record high 2.1Gb/s over 50m POF transmission. the CAP-64 and 64-QAM-OFDM links consume similar powers which are ~2 (~2.5) times of that of NRZ for the single POF link (twin POF links) case.
In this paper, we introduce a novel fast angle and power adaptation method in optical wireless (OW) systems. the fast angle and power adaptive line strip multibeam system (FAPA-LSMS) can identify the optimum spots dis...
详细信息
ISBN:
(纸本)9781467322287
In this paper, we introduce a novel fast angle and power adaptation method in optical wireless (OW) systems. the fast angle and power adaptive line strip multibeam system (FAPA-LSMS) can identify the optimum spots distribution based on a divide and conquer (D&C) algorithm and can achieve a signal-to-noise ratio (SNR) performance comparable to that obtained using the normal APA-LSMS. this results in a significant reduction in the system adaptation time by a factor of 20. the proposed FAPA system makes use of delay adaptation to minimize the delay spread at the receiver. A significant reduction in the delay spread by a factor of 50 can be achieved compared to the non-adaptive LSMS. the proposed system improves the SNR by 50 dB over a conventional diffuse system.
In this paper, we evaluate the performance of the next generation standard IEEE 802.11ac wireless local area network (WLAN) system. IEEE 802.11 for the first time will employ downlink multi-user multi-input multi-outp...
详细信息
In this paper, we evaluate the performance of the next generation standard IEEE 802.11ac wireless local area network (WLAN) system. IEEE 802.11 for the first time will employ downlink multi-user multi-input multi-output (MU-MIMO) technology. Precoding techniques greatly influences the performance of MU-MIMO transmission. We measure these improvements when realistic channel conditions are applied. We compare the performance of channel inversion (CI) and block diagonalization (BD) precoding methods paired with various MIMO detection techniques. From the simulation results, we show the effectiveness of BD precoding compared to CI precoding.
暂无评论