With the rapid development of mobile internet services, the intensive deployment of wireless local area network (WLAN) is inevitable. Traditional WLAN uses carrier sense/collision avoidance (CSMA/CA) mechanism to avoid interference between links as much as possible. In the multi access points (APs) scenario, the traditional CSMA/CA may lead to the flow in the middle (FIM) problem, resulting in a sharp reduction in the throughput of the intermediate nodes and affecting the fairness of the whole network. Existing researches have shown that the FIM problem is more serious in the high density WLAN network. The existing researches on the FIM problem mainly focus on the dynamic optimization of a single parameter, the fairness and performance of the network cannot be well guaranteed. Therefore, this paper proposes a FIM oriented down link (DL) multi-parameter joint dynamic control scheme. AP as a centralized controller, regularly obtains the transmission status of the whole network, reduces the transmission opportunities of the strong AP through adaptive dynamic power and energy detection threshold control (A-DPEC) algorithm, and improves the transmission opportunities of the starvation AP, so as to achieve the performance and fair balance of the whole network. The simulation results show that the proposed scheme outperforms the comparing schemes.

Neighbor node discovery is one of the important steps in a wireless directed ad hoc network. Improving the efficiency of neighbor node discovery can not only reduce the collision during node communication, but also improve the performance of the wireless ad hoc network as a whole. In the Ad-hoc network of directional antennas, by analyzing and summarizing the deficiencies of the neighbor discovery algorithm, this paper proposes a probing and p-probability based two round directional neighbor discovery algorithm (PPTR). The second round adjusts the probability of neighboring neighbor nodes competing for slots based on the number of free slots, successful slots, and collision slots in the first round, thereby reducing the collision of neighboring nodes to reach the maximum number of neighbors discovered within a fixed time. We verified the protocol through network simulation. The simulation results show that the PPTR algorithm and the traditional neighbor discovery algorithm have the same neighbor discovery efficiency when the number of network nodes and the number of time slots are consistent. But The neighbor discovery efficiency increases on average 81.3

In the next generation Wireless Local Area Network (WLAN), IEEE 802.11 regards improving the throughput of the network as a major technical goal. Distributed Multiple Input Multiple Output (D-MIMO) System is an important issue to improve system capacity efficiency, but D-MIMO technology requires extremely high clock consistency between nodes. Therefore, this paper proposes a synchronization protocol based on Orthogonal Frequency Division Multiple Access (OFDMA) for D-MIMO. Firstly, this paper chooses a new clock synchronization process for the synchronization protocol (Two-Way Message Exchange), which is characterized by high synchronization accuracy. Second, we propose and refine the procedure of the synchronization protocol and design the frame structure of the protocol to make it compatible with IEEE 802.11 frame format. The simulation results show that with the increase of the number of APs in D-MIMO, proposed synchronization protocol reduces the overhead by nearly 50

Artificial Intelligence (AI) is one of the hottest research directions nowadays. Machine learning is an important branch of AI. It allows the machine to make its own decisions without human telling the computer exactly what to do. At the same time, Media Access Control (MAC) is also an important technology for the next generation Wireless Local Area Network (WLAN). However, due to transmission collision, noise, interference, channel fading and other reasons, the transmission between access point (AP) and station (STA) may fail. This is limiting the overall performance. If the node can obtain the real-time failure reasons, it can adjust protocol parameters accordingly such as Modulation and Coding Scheme (MCS) and Contention Window (CW). Then, the overall performance of WLAN is improved. Therefore, a machine learning based failure reason identification approach is proposed for the next generation WLAN. In this paper, access environment is divided into four categories: nice, severe collision, deep fading and both deep fading. Different training models are used to train the data. Through our experiments, the accuracy can reach 83

In order to implement an effective directed medium access control and routing protocol in a directed ad hoc network, the node in the network should know the state of the neighboring nodes. However, it is difficult to sense signals in other directions, due to the strong directivity of the directional antenna. It will result in problems such as link collision. In order to solve the above problems, this paper proposes an orthogonal frequency division multiple access (OFDMA) based neighbor discover and tracking protocol for directional ad-hoc network. Then this paper discusses the neighboring state partitioning method based on discovery time and multiple resource unit access and frame format design based on OFDMA. The simulation results show that compared with the directional transmission and reception algorithms protocol, the protocol proposed in this paper increases the number of neighbor discovered nodes by 200 % when the number of neighbor nodes is about 30. The nodes can connect neighbor nodes frequently, and it improves accuracy of neighbor nodes position.

In this paper, we study the directional data transmission of multi-cells. In a high-density cell scenario, if nodes of multi-cell perform data transmission randomly in the Scheduling Period (SP) phase, there may be a large interference between the links of cells using the same frequency. In order to reduce the interference, improve the throughput of the network, and reduce the delay of the network and packet loss rate, we propose a multi-cell cooperative transmission scheme. In our proposed scheme, one cell is set as the primary cell, and one cell is the secondary cell, and a special new frame is proposed. When the nodes of the primary cell starts SP, the data sender of the cell sends the frame to synchronize between cells. The node of the other cell that received the frame performs data transmission at the appointed time point. Through our proposed scheme, the impact of other cells transmitting data on the acknowledgement (ACK) of the cell is greatly reduced. The simulation results show that the proposed scheme improves the anti-interference performance of the network including improving the network throughput and reducing the packet loss rate and packet transmission delay of the network compared with AP Clustering.