TDMA access method and device based on multiple access points
First Claim
1. A TDMA access method for broadcasting a beacon frame from a multi-AP access device to a station (STA) for use in performing time synchronization, the method comprising:
- dividing n access points of a multi-AP access device that serves as a time source of a network into k groups Bi, with 1≦
k≦
n, and with a quantity j of the APs within any group Bi set as Bi={APi1, APi2, . . . APij};
dividing a super-frame having a length of m into k sub-super-frames, with an ith sub-super-frame being made to correspond with a group Bi;
reserving time slots within the ith sub-super-frame, with the quantity of reserved time slots in the ith sub-super-frame being made equal to the quantity j of the APs in the corresponding group Bi;
determining, for a present absolute time slot number (ASN) counted from 1, if ASN % m=(m/k)*(i−
1)+j; and
, when it is determined that ASN % m=(m/k)*(i−
1)+j is true, broadcasting a beacon frame within the corresponding time slot ASN from an APij within a group Bi, wherein 1≦
i≦
k and k is the number of sub-super-frames.
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Accused Products
Abstract
The present invention relates to a TDMA access method and device based on multiple access points. According to the problems that the existing method cannot simultaneously satisfy the demands of timeliness and reliability in actual industrial application and has low resource utilization rate, the present invention takes full consideration of the transmission characteristics and industrial automation application characteristics of wireless networks, and provides a TDMA access method and device based on multiple access points. The main ideas of the method in the present invention are: the multi-access point redundant communication manner is adopted to improve system reliability, beacon frames of multiple access points are utilized to perform time synchronization so as to improve synchronization precision, confirmation messages are fed back with regard to reliable access points to reduce the number of retransmissions, and a modularized multi-access point device design method is adopted to lower the difficulties of device maintenance and management.
6 Citations
12 Claims
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1. A TDMA access method for broadcasting a beacon frame from a multi-AP access device to a station (STA) for use in performing time synchronization, the method comprising:
-
dividing n access points of a multi-AP access device that serves as a time source of a network into k groups Bi, with 1≦
k≦
n, and with a quantity j of the APs within any group Bi set as Bi={APi1, APi2, . . . APij};dividing a super-frame having a length of m into k sub-super-frames, with an ith sub-super-frame being made to correspond with a group Bi; reserving time slots within the ith sub-super-frame, with the quantity of reserved time slots in the ith sub-super-frame being made equal to the quantity j of the APs in the corresponding group Bi; determining, for a present absolute time slot number (ASN) counted from 1, if ASN % m=(m/k)*(i−
1)+j; and
, when it is determined that ASN % m=(m/k)*(i−
1)+j is true, broadcasting a beacon frame within the corresponding time slot ASN from an APij within a group Bi, wherein 1≦
i≦
k and k is the number of sub-super-frames. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification