Systems And Methods For Allocating Timeslots For Unicast Transmissions

Abstract

Systems and methods are described for reducing an end-to-end latency occurring in link layer unicast transmissions by shifting the timeslots in the super frame of the TDMA mode based on membership to a multicast group. In this manner, transmission to all of the multicast subscribers occupy adjacent timeslots, which results in an optimization of slot allocation and improvement of the end-to-end latency for multicast communication.

Description

[0001]This application claims priority to U.S. provisional patent application having Ser. No. 62 / 880,355 filed on Jul. 30, 2019. This and all other referenced extrinsic materials are incorporated herein by reference in their entirety. Where a definition or use of a term in a reference that is incorporated by reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein is deemed to be controlling.FIELD OF THE INVENTION[0002]The field of the invention is multicast communication, such as for use in intra-vehicular wireless sensor networks, Internet of Things, home automation, and low-power devices, for example.BACKGROUND[0003]The following description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced i...

AI Technical Summary

Benefits of technology

The patent text discusses a system and method that can be used with the IEEE 802.15.4 protocol to reduce latency in multicast groups. It suggests that by reallocating timeslots in the super frame, transmissions to individual members of a group can be optimized, resulting in improved end-to-end latency. The system is designed to be adaptable to different protocols, so it can be used with later-developed protocols as well.

Problems solved by technology

However, current standards including Institute of Electrical and Electronics Engineers (IEEE) 802.15.4 do not natively support multicast.

While link layer unicast transmissions offer high reliability due to the re-transmissions based on acknowledgment, they have poor end-to-end latency as individual transmissions are required to each of the multicast subscribers and require high energy consumption.

In contrast, broadcast transmissions have low end-to-end latency and low energy consumption due to a single transmission to all multicast subscribers, but there is lower reliability because of the lack of re-transmissions and acknowledgements.

Thus, while various techniques have been developed to attempt to address the problems identified above, each has its own problems.

However, the 802.11aa standard is a non-deterministic scheme based on CSMA and the GCR service adds overhead depending on the number of retries and becomes inefficient and unnecessary when the link quality is good.

TRM-MAC can be disadvantageous because it does not propose a way to optimize slots allocation in the CFP.

In addition, the CCA operation may fail in the presence of hidden nodes, and therefore, the proposed prioritized-CSMA channel access mechanism does not completely avoid the collision between NACK messages.

Unfortunately, the algorithm uses broadcast slots for its multicast transmission, which is unreliable.

In addition, the algorithm is quite complex to put in place and requires some computational power.

The algorithm may also require bigger timeslots adding latency to the overall slot frame.

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