Efficient MAC layer scheduling method based on OFDMA

Abstract

The invention discloses an efficient MAC (Media Access Control) layer scheduling method based on OFDMA (Orthogonal Frequency Division Multiple Access), which is mainly applied to TDMA (Time Division Multiple Access) network communication, for example, a WIA-FA industrial wireless network system is based on a TDMA transmission scheduling mechanism, each wireless communication device in the system realizes time synchronization based on a timestamp, and each wireless communication device comprises a wireless access point and a field device. The wireless communication equipment configures default triggering OFDMA uplink and OFDMA downlink functions, and assigns and sets wireless access point OFDMA RU resource allocation and RU resource information of field equipment through a register; the same TDMA time slot number is distributed to the field device, and the field device forcibly performs OFDMA synchronous transmission in the TDMA time slot based on a clock; the wireless access point synchronously receives the data of the plurality of field devices based on the OFDMA, and simultaneously sends the data of the plurality of field devices based on the OFDMA, so that TDMA communication time slot resources are saved, and an efficient MAC layer communication scheduling scheme under a TDMA mechanism is realized.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to an OFDMA-based efficient MAC layer scheduling method. Background Art

[0002] Key industries such as manufacturing, electricity, energy, and transportation usually use high-speed wireless communication technologies such as WIA-FA, WiFi, and 5G for wireless data transmission, but some scenarios require high real-time and high reliability scenarios. There is currently no reliable wireless communication technology. Wireless communication technologies with the underlying time division multiple access (TDMA) access mechanism, such as WIA-FA, can guarantee a relatively certain communication delay, but in large-scale networks, multiple field terminal wireless devices need to transmit uplink data at the same time, which will cause a large number of queues waiting for TDMA transmission time slots. The congestion phenomenon, communication efficiency and wireless resource utilization are not as expected.

[0003] When the aggregated data frame or management frame of the wireless access point (AP) sends downlink data to multiple field devices (STA) via broadcast, the field devices reply with confirmation frames (ACK) in turn, which wastes a lot of communication resources and increases latency; if the field devices do not reply with ACK, the communication reliability cannot be guaranteed.

[0004] Orthogonal Frequency Division Multiple Access (OFDMA) is a key technology in Wi-Fi 6 (802.11ax), which allows multiple users to communicate using different subcarrier sets at the same time, thereby improving spectrum utilization and system capacity. However, OFDMA in WiFi networks is not triggered in every transmission, and its triggering mechanism depends on multiple factors such as network congestion, client density, service type, AP scheduling strategy, channel conditions, etc.

[0005] OFDMA technology is suitable for synchronous transmission of small data under multiple devices, greatly improving communication transmission efficiency, and is suitable for small data and high real-time transmission scenarios such as industrial acquisition and control. WiFi's Carrier Sense Multiple Access (CSMA) technology is not suitable for industrial control scenarios, and the WIA-FA industrial wireless technology based on the TDMA mechanism has no OFDMA technical measures. Therefore, it is necessary to propose an efficient MAC layer scheduling method based on OFDMA to solve the above problems. Summary of the invention

[0006] The invention provides an OFDMA-based efficient MAC layer scheduling method, which realizes an efficient MAC layer communication scheduling scheme under a TDMA mechanism.

[0007] The present invention provides an OFDMA-based efficient MAC layer scheduling method, the method comprising:

[0008] The WIA-FA industrial wireless network system is based on the TDMA transmission scheduling mechanism. Each wireless communication device in the system implements time synchronization based on timestamps. The wireless communication device includes a wireless access point and a field device. The wireless communication device is configured to trigger the OFDMA uplink and OFDMA downlink functions by default. The OFDMA RU resource allocation of the wireless access point and the RU resource information of the field device are set by specifying the register.

[0009] The same TDMA time slot number is allocated to the field devices, and the field devices are forced to perform OFDMA synchronous transmission in the TDMA time slot based on the clock;

[0010] The wireless access point synchronously receives data from multiple field devices based on OFDMA, and simultaneously sends data from multiple field devices based on OFDMA.

[0011] Furthermore, the method also includes: the wireless access point occupies the time slot of the pre-configured TDMA, and based on OFDMA modulation, sends downlink data to multiple field devices; at the same time, the multiple field devices reply ACK on their designated RUs, the wireless access point synchronously receives ACKs of the multiple field devices based on OFDMA, determines which field devices have not successfully received the data through the ACK information, and resends the data to the field devices that have not successfully received the data.

[0012] Furthermore, the method also includes: the on-site equipment occupies the time slot of the pre-configured TDMA, turns on the uplink OFDMA function, the on-site equipment sends data in the pre-configured TDMA time slot and in the RUs divided respectively at the same time, the wireless access point receives the data and replies with ACK; the on-site equipment determines whether the data is sent successfully based on the content of the ACK replied by the wireless access point, and resends the data if it is not sent successfully.

[0013] Furthermore, the method also includes: the wireless communication device configures the OFDMA function and supports the configuration of whether to trigger the uplink and downlink ACK confirmation function; in the absence of the ACK confirmation function, the wireless communication device supports the configuration of the number of uplink and downlink OFDMA transmissions; if the ACK confirmation function is configured, the wireless communication device supports the configuration of the number of OFDMA data retransmissions and the retransmission rate level.

[0014] Furthermore, the method also includes: the wireless communication device configures an OFDMA function, and using the OFDMA function, the wireless communication device redundantly sends the transmitted data on multiple allocated RUs.

[0015] Furthermore, the method also includes: the uplink OFDMA function of the wireless communication device triggers the uplink OFDMA data transmission based on the scheduling frame sent downlink by the wireless access point; if the wireless access point sends the scheduling frame data in the TDMA downlink time slot; the wireless access point enters the uplink OFDMA data receiving state, and the field device triggers the use of OFDMA to send uplink data to the wireless access point in the next time slot based on the scheduling frame data information received in the TDMA time slot of the wireless access point.

[0016] The present invention has the following beneficial effects: an efficient MAC layer scheduling method based on OFDMA of the present invention realizes the optimal scheduling scheme of wireless communication resources in large-scale, small-data and high-concurrency scenarios under industrial control scenarios, that is, it forces the use of OFDMA uplink transmission technology to perform parallel transmission of multi-device data, saving TDMA communication time slot resources; and fully combines the characteristics of the broadcast mode under the star networking architecture to solve the problem of low efficiency of replying ACK separately in the broadcast mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the embodiments are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 The present invention provides a flowchart of an efficient OFDMA-based MAC layer scheduling method. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. The technical solutions provided by the embodiments of the present invention are described in detail below in conjunction with the drawings.

[0020] See also Figure 1 , an efficient MAC layer scheduling method based on OFDMA provided by the present invention, the method comprising:

[0021] S101, the WIA-FA industrial wireless network system is based on the TDMA transmission scheduling mechanism. Each wireless communication device in the system implements time synchronization based on a timestamp. The wireless communication device includes a wireless access point and a field device. The wireless communication device is configured to trigger the OFDMA uplink and OFDMA downlink functions by default. The OFDMA RU resource allocation of the wireless access point and the RU resource information of the field device are set by specifying the register.

[0022] Specifically, the wireless communication system is based on the TDMA transmission scheduling mechanism. Each wireless communication device in the wireless communication system implements strict time synchronization based on timestamps. Data transmission is based on microsecond time slot scheduling, which has the basis for OFDMA synchronous transmission. In this embodiment, the wireless communication system is a WIA-FA industrial wireless network system. In addition, the wireless communication system can also be other real-time wireless communication systems that can be used in manufacturing, electricity, energy, transportation and other industrial industries. RU is a resource unit (RU).

[0023] S102, allocating the same TDMA time slot number to the field devices, and the field devices are forced to perform OFDMA synchronous transmission in the TDMA time slot based on the clock.

[0024] Specifically, this method is aimed at industrial control and acquisition scenarios, and the data types transmitted are small data, high concurrency, and frequent transmission.

[0025] S103, the wireless access point synchronously receives data of multiple field devices based on OFDMA, and simultaneously sends data of multiple field devices based on OFDMA.

[0026] As an optional implementation, the method further includes: the wireless access point occupies the time slot of the pre-configured TDMA, based on OFDMA modulation, sends downlink data to multiple field devices; at the same time, the multiple field devices reply ACK on the RUs designated by them, the wireless access point synchronously receives ACKs of multiple field devices based on OFDMA, determines which field devices have not successfully received the data through the ACK information, and resends the data to the field devices that have not successfully received the data. The ACK information of the field device can be aggregated and sent with the uplink control frame, data frame, management frame, etc.

[0027] As an optional implementation, the method further includes: the field device occupies the time slot of the preconfigured TDMA, turns on the uplink OFDMA function, the field device sends data in the preconfigured TDMA time slot and in the RUs divided accordingly, the wireless access point receives the data and replies with an ACK; the field device determines whether the data is sent successfully based on the content of the ACK replied by the wireless access point, and resends the data if the data is not sent successfully.

[0028] As an optional implementation, the method also includes: the wireless communication device configures the OFDMA function and supports the configuration of whether to trigger the uplink and downlink ACK confirmation function; in the absence of the ACK confirmation function, the wireless communication device supports the configuration of the number of uplink and downlink OFDMA transmissions to ensure the reliability of data transmission; if the ACK confirmation function is configured, the wireless communication device supports the configuration of the number of OFDMA data retransmissions and the retransmission rate level.

[0029] As an optional implementation, the method further includes: the wireless communication device configures an OFDMA function, and using the OFDMA function, the wireless communication device redundantly sends the transmitted data on multiple allocated RUs, thereby improving the reliability of data transmission.

[0030] As an optional implementation, the method further includes: an uplink OFDMA function of the wireless communication device triggers uplink OFDMA data transmission based on a scheduling frame sent downlink by a wireless access point; if the wireless access point sends the scheduling frame data in a TDMA downlink time slot; the wireless access point enters a state of receiving uplink OFDMA data, and the field device triggers the use of OFDMA to send uplink data to the wireless access point in the next time slot based on the scheduling frame data information received in the TDMA time slot of the wireless access point.

[0031] The above-described embodiments of the present invention do not limit the protection scope of the present invention.

Claims

1. An efficient MAC layer scheduling method based on OFDMA, characterized in that: The method comprises: The WIA-FA industrial wireless network system is based on the TDMA transmission scheduling mechanism. Each wireless communication device in the system implements time synchronization based on timestamps. The wireless communication device includes a wireless access point and a field device. The wireless communication device is configured to trigger the OFDMA uplink and OFDMA downlink functions by default. The OFDMA RU resource allocation of the wireless access point and the RU resource information of the field device are set by specifying the register. The same TDMA time slot number is allocated to the field devices, and the field devices are forced to perform OFDMA synchronous transmission in the TDMA time slot based on the clock; The wireless access point synchronously receives data from multiple field devices based on OFDMA, and simultaneously sends data from multiple field devices based on OFDMA.

2. The efficient MAC layer scheduling method based on OFDMA as claimed in claim 1, characterized in that: The method further comprises: The wireless access point occupies the pre-configured TDMA time slot and sends downlink data to multiple field devices based on OFDMA modulation. At the same time, multiple field devices reply ACK on their designated RUs. The wireless access point synchronously receives ACKs from multiple field devices based on OFDMA, determines which field devices have not successfully received the data through the ACK information, and resends the data to the field devices that have not successfully received the data.

3. The efficient MAC layer scheduling method based on OFDMA as claimed in claim 1, characterized in that: The method further comprises: The field equipment occupies the pre-configured TDMA time slot and turns on the uplink OFDMA function. The field equipment sends data in the pre-configured TDMA time slot and in the RUs designated by them at the same time. The wireless access point receives the data and replies with ACK. The field equipment determines whether the data is sent successfully based on the ACK content replied by the wireless access point. If not, the data is resent.

4. The efficient MAC layer scheduling method based on OFDMA as claimed in claim 1, characterized in that: The method further comprises: The wireless communication device is configured with the OFDMA function and supports the configuration of whether to trigger the uplink and downlink ACK confirmation function; in the absence of the ACK confirmation function, the wireless communication device supports the configuration of the number of uplink and downlink OFDMA transmissions; if the ACK confirmation function is configured, the wireless communication device supports the configuration of the number of OFDMA data retransmissions and the retransmission rate level.

5. The OFDMA-based efficient MAC layer scheduling method according to claim 1, characterized in that: The method further comprises: The wireless communication device is configured with an OFDMA function. By using the OFDMA function, the wireless communication device redundantly sends the transmitted data on multiple allocated RUs.

6. The efficient MAC layer scheduling method based on OFDMA as claimed in claim 1, characterized in that: The method further comprises: The uplink OFDMA function of the wireless communication device triggers the uplink OFDMA data transmission based on the scheduling frame sent downlink by the wireless access point; if the wireless access point sends the scheduling frame data in the TDMA downlink time slot; the wireless access point enters the uplink OFDMA data receiving state, and the field equipment triggers the use of OFDMA to send uplink data to the wireless access point in the next time slot based on the scheduling frame data information received in the TDMA time slot of the wireless access point.

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