Traditional cellular network requires that a user equipment(UE) should associate to the same base station(BS) in both the downlink(DL) and the uplink(UL). Based on dual connectivity(DC) introduced in LTE-Advanced R12,...Traditional cellular network requires that a user equipment(UE) should associate to the same base station(BS) in both the downlink(DL) and the uplink(UL). Based on dual connectivity(DC) introduced in LTE-Advanced R12, DL/UL decouple access scheme has been proposed, which is especially suitable for heterogeneous networks(Het Nets). This paper is the pioneer to take the DL/UL decouple access scheme into consideration and develop a novel resource allocation algorithm in a two-tier Het Net to improve the total system throughput in the UL and ease the load imbalance between macro base stations(MBSs) and pico base stations(PBSs). A model is formulated as a nonlinear integer programming, and the proposed algorithm is a sub-optimal algorithm based on the graph theory. First, an undirected and weighted interference graph is obtained. Next, the users are grouped to let users with large mutual interferences to be assigned to different clusters. Then, the users in different clusters are allocated to different resource blocks(RBs) by using the Hungarian algorithm. Simulation results show that the proposed algorithm can provide great promotions for both the total system throughput and the average cell edge user throughput and successfully ease the load imbalance between MBSs and PBSs.展开更多
In this paper, an Independent Window-Access(IWA) scheme is proposed, and the performance of an input-buffered ATM switching fabric with the IWA scheme is analysed by means of a probability generating function approach...In this paper, an Independent Window-Access(IWA) scheme is proposed, and the performance of an input-buffered ATM switching fabric with the IWA scheme is analysed by means of a probability generating function approach, the closed formulas of the average cell delay and the maximum throughput are given, and results show that the IWA scheme makes the switching fabric have better performances than traditional window-access scheme. The computer simulation results are in good agreement with these analytical results.展开更多
This article presents a dynamic random access scheme for orthogonal frequency division multiple access （OFDMA） systems. The key features of the proposed scheme are it is a combination of both the distributed and the...This article presents a dynamic random access scheme for orthogonal frequency division multiple access （OFDMA） systems. The key features of the proposed scheme are it is a combination of both the distributed and the centralized schemes, it can accommodate several delay sensitivity classes, and it can adjust the number of random access channels in a media access control （MAC） frame and the access probability according to the outcome of Mobile Terminals access attempts in previous MAC frames. For floating populated packet-based networks, the proposed scheme possibly leads to high average user satisfaction.展开更多
Random Access Channel （RACH） is an uplink contention-based transport channel usually used for initial channel access, bandwidth request, etc. How to use RACH resources effectively is very important in wireless corrn...Random Access Channel （RACH） is an uplink contention-based transport channel usually used for initial channel access, bandwidth request, etc. How to use RACH resources effectively is very important in wireless corrnunication systel In this paper, a dynamical RACH allocation scheme is proposed for Orthogonal Frequency-Division Multiple Access （OFDMA） systen. Based on the PseudoBayesian algorithm, this mechanism predicts the number of RACHs for the next frame according to the current load. A new dynamic RACH assignment algorithm and an adaptive access probability method are adopted by the proposed scheme to irrprove the utilization ratio of RACH resources and increase the successful access rate. Numerical simulation shows that the proposed strategy achieves both improvement in the utilization ratio of RACHs and reduction in the access delay compared with other RACH allocation schemes.展开更多
As the share of photovoltaic power generation in power system has increased year by year, the optimization choice of access system schemes become one of the first and most important problems in grid before admitting p...As the share of photovoltaic power generation in power system has increased year by year, the optimization choice of access system schemes become one of the first and most important problems in grid before admitting photovoltaic power generation. Therefore, this article takes a proposed distributed photovoltaic as an example to research and analyze two kinds of high density multiple access points distributed photovoltaic access system schemes. The emphasis is making a comprehensive comparison and selection among the aspect of active power loss and economic benefit, etc. In the premise of ensuring the normal power generation of the photovoltaic system, it puts forward the recommended scheme that can help to spontaneous self-consumption, elimination on the spot, effectively decrease network loss and economic benefit.展开更多
This paper provides a review on the diversity techniques of IDMA (Interleave Division Multiple Access) technology in underwater wireless IDMA employs interleavers as the only means in order to distinguish the users. T...This paper provides a review on the diversity techniques of IDMA (Interleave Division Multiple Access) technology in underwater wireless IDMA employs interleavers as the only means in order to distinguish the users. This paper provides a comprehensive study of diversity techniques in IDMA scheme to mitigate the fading issue. In this paper, we compare the different generation diversity techniques in IDMA scheme on computational complexity, bit error rate and memory requirement. Recent advancement in underwater communication is modulation techniques, multiplexing techniques and multiple access techniques. Underwater communication channel is characterized.展开更多
Well-established fact shows that the fixed spectrum allocation policy conveys to the low spectrum utilization. The cognitive radio technique promises to improve the low efficiency. This paper proposes an optimized acc...Well-established fact shows that the fixed spectrum allocation policy conveys to the low spectrum utilization. The cognitive radio technique promises to improve the low efficiency. This paper proposes an optimized access strategy combining overlay scheme and underlay scheme for the cognitive radio. We model the service state of the system as a continuous-time Markov model. Based on the service state, the overlay manner or/and the underlay manner is/are used by the secondary users. When the primary user is not transmitting and only one secondary user has the requirement to transmit, the secondary system adopts the overlay scheme. When the primary user is transmitting and the secondary users want to transmit simultaneously, an underlay scheme with an access probability is adopted. We obtain the optimal access probability in a closed form which maximizes the overall system throughput.展开更多
In this paper, we propose a novel space efficient secret sharing scheme on the basis of minimal linear codes, which satisfies the definition of a computationally efficient secret sharing scheme. In the scheme, we part...In this paper, we propose a novel space efficient secret sharing scheme on the basis of minimal linear codes, which satisfies the definition of a computationally efficient secret sharing scheme. In the scheme, we partition the underlying minimal linear code into disjoint classes, establishing a one-to-one correspondence between the minimal authorized subsets of participants and the representative codewords of all different classes. Each participant, with only one short share transmitted through a public channel, can share a large secret. Therefore, the proposed scheme can distribute a large secret in practical applications such as secure information dispersal in sensor networks and secure multiparty computation.展开更多
基金supported by the National Natural Science Foundation General Program of China under Grant No.61171110the National Basic Research Program of China under Grant No.2013CB329003
文摘Traditional cellular network requires that a user equipment(UE) should associate to the same base station(BS) in both the downlink(DL) and the uplink(UL). Based on dual connectivity(DC) introduced in LTE-Advanced R12, DL/UL decouple access scheme has been proposed, which is especially suitable for heterogeneous networks(Het Nets). This paper is the pioneer to take the DL/UL decouple access scheme into consideration and develop a novel resource allocation algorithm in a two-tier Het Net to improve the total system throughput in the UL and ease the load imbalance between macro base stations(MBSs) and pico base stations(PBSs). A model is formulated as a nonlinear integer programming, and the proposed algorithm is a sub-optimal algorithm based on the graph theory. First, an undirected and weighted interference graph is obtained. Next, the users are grouped to let users with large mutual interferences to be assigned to different clusters. Then, the users in different clusters are allocated to different resource blocks(RBs) by using the Hungarian algorithm. Simulation results show that the proposed algorithm can provide great promotions for both the total system throughput and the average cell edge user throughput and successfully ease the load imbalance between MBSs and PBSs.
文摘In this paper, an Independent Window-Access(IWA) scheme is proposed, and the performance of an input-buffered ATM switching fabric with the IWA scheme is analysed by means of a probability generating function approach, the closed formulas of the average cell delay and the maximum throughput are given, and results show that the IWA scheme makes the switching fabric have better performances than traditional window-access scheme. The computer simulation results are in good agreement with these analytical results.
文摘This article presents a dynamic random access scheme for orthogonal frequency division multiple access （OFDMA） systems. The key features of the proposed scheme are it is a combination of both the distributed and the centralized schemes, it can accommodate several delay sensitivity classes, and it can adjust the number of random access channels in a media access control （MAC） frame and the access probability according to the outcome of Mobile Terminals access attempts in previous MAC frames. For floating populated packet-based networks, the proposed scheme possibly leads to high average user satisfaction.
基金Acknowledgements This paper was supported by the National Natural Science Foundation of China under Cants No.60971125, No.61121001 the National Key Project under Cant No. 2011ZX03005-005+2 种基金 the project under Cant No. 201105.Acknowledgements This paper was supported by the National Natural Science Foundation of China under Crants No.60971125, No.61121001 the National Key Project under Cant No. 2011ZX03005-005 the project under Cant No. 201105.
文摘Random Access Channel （RACH） is an uplink contention-based transport channel usually used for initial channel access, bandwidth request, etc. How to use RACH resources effectively is very important in wireless corrnunication systel In this paper, a dynamical RACH allocation scheme is proposed for Orthogonal Frequency-Division Multiple Access （OFDMA） systen. Based on the PseudoBayesian algorithm, this mechanism predicts the number of RACHs for the next frame according to the current load. A new dynamic RACH assignment algorithm and an adaptive access probability method are adopted by the proposed scheme to irrprove the utilization ratio of RACH resources and increase the successful access rate. Numerical simulation shows that the proposed strategy achieves both improvement in the utilization ratio of RACHs and reduction in the access delay compared with other RACH allocation schemes.
文摘As the share of photovoltaic power generation in power system has increased year by year, the optimization choice of access system schemes become one of the first and most important problems in grid before admitting photovoltaic power generation. Therefore, this article takes a proposed distributed photovoltaic as an example to research and analyze two kinds of high density multiple access points distributed photovoltaic access system schemes. The emphasis is making a comprehensive comparison and selection among the aspect of active power loss and economic benefit, etc. In the premise of ensuring the normal power generation of the photovoltaic system, it puts forward the recommended scheme that can help to spontaneous self-consumption, elimination on the spot, effectively decrease network loss and economic benefit.
文摘This paper provides a review on the diversity techniques of IDMA (Interleave Division Multiple Access) technology in underwater wireless IDMA employs interleavers as the only means in order to distinguish the users. This paper provides a comprehensive study of diversity techniques in IDMA scheme to mitigate the fading issue. In this paper, we compare the different generation diversity techniques in IDMA scheme on computational complexity, bit error rate and memory requirement. Recent advancement in underwater communication is modulation techniques, multiplexing techniques and multiple access techniques. Underwater communication channel is characterized.
文摘Well-established fact shows that the fixed spectrum allocation policy conveys to the low spectrum utilization. The cognitive radio technique promises to improve the low efficiency. This paper proposes an optimized access strategy combining overlay scheme and underlay scheme for the cognitive radio. We model the service state of the system as a continuous-time Markov model. Based on the service state, the overlay manner or/and the underlay manner is/are used by the secondary users. When the primary user is not transmitting and only one secondary user has the requirement to transmit, the secondary system adopts the overlay scheme. When the primary user is transmitting and the secondary users want to transmit simultaneously, an underlay scheme with an access probability is adopted. We obtain the optimal access probability in a closed form which maximizes the overall system throughput.
基金Supported by the National Natural Science Foundation of China (11271237)
文摘In this paper, we propose a novel space efficient secret sharing scheme on the basis of minimal linear codes, which satisfies the definition of a computationally efficient secret sharing scheme. In the scheme, we partition the underlying minimal linear code into disjoint classes, establishing a one-to-one correspondence between the minimal authorized subsets of participants and the representative codewords of all different classes. Each participant, with only one short share transmitted through a public channel, can share a large secret. Therefore, the proposed scheme can distribute a large secret in practical applications such as secure information dispersal in sensor networks and secure multiparty computation.
