Uplink dynamic time slot reservation method for phased array antenna scattering points in multi-point TDMA networks

Abstract

This invention proposes a dynamic uplink time slot reservation method for multi-point TDMA networks using phased array antenna scattering points, belonging to the field of non-line-of-sight burst wireless communication technology. This method employs an AB time slot combination dynamic allocation approach, with both uplink and downlink operating under TDMA, increasing the possibility of proactive uplink time slot reservation while maintaining the management center's allocation of time slots. Compared to downlink CSMA and uplink TDMA, this method effectively reduces the waiting time for bursty uplink services at random nodes in low-speed TDMA networks. When multiple uplink services are concurrent, prioritization allows the management center to queue various service flows and allocate time slots as needed, achieving optimal channel occupancy configuration.

Description

Technical Field

[0001] This invention relates to the field of non-line-of-sight burst wireless communication technology, and in particular to an uplink dynamic time slot reservation method for phased array antenna scattering points in multi-point TDMA networks, which can effectively improve the transmission latency of uplink services. Background Technology

[0002] Traditional scattering communication uses point-to-point communication based on directional antennas. With the development of phased array technology and changes in application requirements, we are exploring application methods that provide regional network coverage from a center to multiple peripheries. This application increases the communication coverage area compared to traditional communication methods, and achieves a longer communication distance per hop compared to line-of-sight wireless communication methods such as microwave.

[0003] A point-to-multipoint TDMA network is constructed using a phased array antenna at the central node and directional antennas at the peripheral nodes. When the communication distance is extremely long, the communication rate is very low, making the allocation and division of time slots particularly important. Excellent time slot allocation strategies can achieve communication capacity closer to the Shannon limit and better channel allocation for network layer services. However, current technologies lack an uplink dynamic time slot reservation scheme based on appropriate time slot allocation. Summary of the Invention

[0004] To address the issue that in centralized networks with low communication rates, the process of the central node probing the service demands of peripheral nodes during time slot allocation is unrelated to the actual service demands, this invention proposes a dynamic uplink time slot reservation method for multi-point TDMA networks using phased array antenna scattering points. This method binds the real-time uplink service demand with the central node's process of probing the service demands of peripheral nodes, allocating time slots on demand. This avoids the problem of the probing process occupying the channel when there is no uplink service demand, thus improving channel utilization.

[0005] This invention is achieved through the following technical solution:

[0006] The uplink dynamic time slot reservation method for phased array antenna scattering points in a multi-point TDMA network includes the following steps:

[0007] Step 1: Divide the MAC layer time slots into two types, A and B, and let them appear alternately. During network synchronization, the A and B time slots of each node are aligned.

[0008] Step 2: The peripheral node initiates a reservation with the central node in time slot B according to the business needs and priorities; then, it receives the central node's reply in time slot A. If it does not receive the reply, it adjusts the priority and reservation sending frequency according to the time. If it receives the reply, it sends the business in the adjacent time slot of length T. After the business is sent, the priority and sending frequency of the business are adjusted to zero. The time slot of length T consists of one or more consecutive time slots B and A.

[0009] Step 3: When the central node is idle in time slot A, it detects its own services and adds them to the priority contention sequence. When it is idle in time slot B, it scans and receives services from peripheral nodes within and outside the network. If a reservation is received, the peripheral node's services are added to the priority contention sequence.

[0010] Step 4: The central node selects the highest priority service from the priority contention sequence. If it is the central node's own service, it processes the service in time slot A. If it is the service of an external node, it sends a reply to the service source node in time slot A, and then receives the service sent by the service source node in the adjacent time slot of length T.

[0011] Compared with the prior art, the advantages of the present invention are:

[0012] 1. In existing centralized wireless networking systems, when the topology is simplified to point-to-multipoint, downlink CSMA and uplink TDMA are often used. Compared with this, this invention can effectively reduce the waiting time of random nodes for bursty uplink services when the communication rate is very low. When multiple uplink services are concurrent, with priority, the management center can queue each service flow and allocate time slots as needed to achieve optimal channel occupancy configuration.

[0013] 2. This invention can combine orthogonal frequency hopping diversity and multi-beam reception technology to solve the priority ordering problem of time slot allocation when uplink services are concurrent. Attached Figure Description

[0014] Figure 1 This is a schematic diagram illustrating the application scenario of the present invention.

[0015] Figure 2 This is a schematic diagram of the AB time slot structure of the present invention.

[0016] Figure 3 This is a schematic diagram of the reservation communication process of the present invention.

[0017] Figure 4 This is a flowchart of the upstream reservation process of the present invention. Detailed Implementation

[0018] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples.

[0019] A method for uplink dynamic time slot reservation in a multi-point TDMA network using phased array antenna scattering points includes the following steps:

[0020] Step 1: Divide the MAC layer time slots into two types, A and B, and let them appear alternately. When the whole network is synchronized, the A and B time slots of each node are aligned. That is, although the A and B time slots have the same length, they are perceived as different time slots because they are distinguished by different labels.

[0021] Step 2: The peripheral node initiates a reservation with the central node in time slot B according to the business needs and priorities; then, it receives the central node's reply in time slot A. If it does not receive the reply, it adjusts the priority and reservation sending frequency according to the time. If it receives the reply, it sends the business in the adjacent time slot of length T. After the business is sent, the priority and sending frequency of the business are adjusted to zero. The time slot of length T consists of one or more consecutive time slots B and A.

[0022] Step 3: When the central node is idle in time slot A, it detects its own services and adds them to the priority contention sequence. When it is idle in time slot B, it scans and receives services from peripheral nodes within and outside the network. If a reservation is received, the peripheral node's services are added to the priority contention sequence.

[0023] Step 4: The central node selects the highest priority service from the priority contention sequence. If it is the central node's own service, it processes the service in time slot A. If it is the service of an external node, it sends a reply to the service source node in time slot A, and then receives the service sent by the service source node in the adjacent time slot of length T.

[0024] This method divides MAC layer time slots into two types, A and B, which alternate. The AB time slot is the shortest in the diversified time slot design, and other time slot types are combinations of AB time slots. During service communication, the central node performs time slot allocation after comprehensively considering uplink and downlink service requirements. The signaling frame used in the uplink time slot reservation process occupies one A or B time slot. When an external node has a service transmission requirement, it will occupy the B time slot for uplink reservation. After receiving the reservation, the central node will reply with the reservation result using the A time slot.

[0025] In this method, time slots allocated with the central node as the transmission source all start with time slot A, and time slots allocated with the peripheral node as the transmission source all start with time slot B. The allocated time slots can be time slots A and B, or other time slot structures containing multiple sets of A and B.

[0026] In addition, when the central node allocates time slots for services, the time slot length does not exceed the threshold Tth, which is related to the fading period of the scattering channel. Several idle B time slots are reserved between service allocation periods to reserve service reservation space for the uplink channel when services are busy. The number of idle B time slots is related to the number of peripheral nodes in the network and the number of known uplink service demands.

[0027] Peripheral nodes occupy time slot B for uplink reservation. This can be combined with orthogonal frequency hopping diversity technology to ensure that signals from multiple peripheral nodes initiating reservations at the central node receiver do not collide.

[0028] Peripheral nodes occupy time slot B to make uplink reservations. The central node may be in other states and therefore may not receive the reservation. The peripheral nodes will dynamically adjust the reservation initiation frequency based on the time it takes to receive a response to the target reservation, and continue to initiate reservations until a response to the target reservation is received.

[0029] When the central node is in an idle B time slot, it will sequentially perform a multi-beam receiving process with the receiving beam pointing in the direction of all peripheral nodes in the network. If the number of peripheral nodes in the network exceeds the number of beams received in a single operation, it will perform time-division scanning coverage.

[0030] The central node's multi-beam reception process can employ different frequencies for beam reception, combined with orthogonal frequency hopping diversity technology to achieve time slot multiplexing, thus enabling the simultaneous reception of uplink reservations from different peripheral nodes.

[0031] Here is a specific example:

[0032] exist Figure 1 In the application scenario shown, the time slot structure for synchronous operation after all nodes join the network is as follows: Figure 2 As shown, the conditions under which an uplink reservation is accepted by the central node are:

[0033] 1. Good channel;

[0034] 2. The central node receives the beam pointing to the peripheral node that initiated the reservation;

[0035] 3. The frequency hopping pattern received by the central node is the same as the frequency hopping pattern sent by the peripheral node that initiated the reservation;

[0036] 4. The central node is in an idle B time slot, which is in the default receiving state.

[0037] After receiving a reservation from a peripheral node, the central node replies in time slot A, but not necessarily in the adjacent time slot A. The allocation of time slots is dynamically controlled by priority relationships. As a result, there may be situations where the same peripheral node's reservation is received multiple times. The service priority carried in the reservation is based on the last reservation before sending the reply. The central station can compete for and allocate service time slots based on the service priority carried in the reservation.

[0038] When the uplink service wins in priority contention, the central node will use time slot A to reply to the service source node. The reply will include the service time slot allocation result, and will allocate the immediately adjacent time slot of length T, starting with time slot B, to the service source node. <Tth。

[0039] After receiving the reply, the service source node will send the service in the adjacent time slot of length T, starting with time slot B, according to the service time slot allocation result carried in the reply. The central node will simultaneously receive this service, completing one reservation communication process. Figure 3 As shown.

[0040] When considering the time slot allocation results, the central node aims to transmit the current service as quickly as possible under the current channel conditions. However, when the service volume is large or the channel conditions are poor, a single scheduled communication process cannot transmit the service from the service source node in one go. In this case, the node will recalculate the priority based on the remaining service and start a new scheduled communication process.

[0041] Figure 4 A flowchart of the uplink reservation process for the central node and peripheral nodes is provided.

[0042] Peripheral nodes:

[0043] Step 1: Based on business needs and priorities, initiate a reservation with the central node in time slot B;

[0044] Step 2: Receive the reply from the central node in time slot A. If no reply is received, adjust the priority and scheduled transmission frequency according to time. If a reply is received, transmit the service in the immediately adjacent time slot of length T.

[0045] Step 3: Send the service in the allocated T-length time slot, adjust the priority and scheduled sending frequency. If the service is completed, adjust the priority and sending frequency to zero.

[0046] Central node:

[0047] Step 1: During idle B time slots, scan and receive data from peripheral nodes within the network. If the data is received, add the service to the priority contention sequence.

[0048] Step 2: When the service wins the competition, allocate a time slot and send a reply to the service source node;

[0049] Step 3: Receive the service from the source node in the adjacent T-length time slot.

[0050] In summary, this invention employs an AB time slot combination dynamic allocation method, with both uplink and downlink operating under a TDMA system. This increases the likelihood of uplink proactive time slot reservation while maintaining the management center's control over time slot allocation. Compared to downlink CSMA and uplink TDMA, this invention effectively reduces the waiting time for bursty uplink services at random nodes in low-speed TDMA networks. When multiple uplink services are concurrent, prioritization allows the management center to queue various service flows and allocate time slots as needed, achieving optimal channel occupancy.

Claims

1. A method for uplink dynamic time slot reservation in a multi-point TDMA network using phased array antenna scattering points, characterized in that, Includes the following steps: Step 1: Divide the MAC layer time slots into two types, A and B, and let them appear alternately. The lengths of time slots A and B are equal. When the whole network is synchronized, the A and B time slots of each node are aligned. That is, the A time slots of different nodes are aligned with the A time slots, and the B time slots are aligned with the B time slots. Step 2: The peripheral nodes initiate a reservation with the central node in time slot B based on business needs and priorities. Then, the response from the central node is received in time slot A. If it is not received, the priority and scheduled transmission frequency are adjusted according to the time. If it is received, the service is sent in the adjacent time slot of length T. After the service is sent, the priority and transmission frequency of the service are adjusted to zero. The time slot of length T consists of one or more consecutive time slots B and A. Step 3: When the central node is idle in time slot A, it detects its own services and adds them to the priority contention sequence. When it is idle in time slot B, it scans and receives services from peripheral nodes within and outside the network. If a reservation is received, the peripheral node's services are added to the priority contention sequence. Step 4: The central node selects the highest priority service from the priority contention sequence. If it is the central node's own service, it processes the service in time slot A. If it is the service of an external node, it sends a reply to the service source node in time slot A, and then receives the service sent by the service source node in the adjacent time slot of length T.

Images