US-12621846-B2 - Reservation signal forwarding using 2-stage sidelink control information (SCI)

US12621846B2US 12621846 B2US12621846 B2US 12621846B2US-12621846-B2

Abstract

The methods and systems discussed herein describe a first wireless communication device receiving reservation signals from two other wireless communication devices, each reservation signal identifying one or more time-slots reserved for data transmissions and a data priority level associated with the data transmissions. When the first wireless communication device determines that the reservation signals have at least one common identified time-slot, the first wireless communication device transmits a forwarded reservation signal, which identifies the time-slots reserved by the wireless communication device with the higher data priority level, to the wireless communication device with a lower data priority level. The wireless communication device that receives the forwarded reservation signal determines whether to transmit data during the time-slots identified in the forwarded reservation signal.

Inventors

Amit Kalhan
Masato Fujishiro
Henry Chang

Assignees

KYOCERA CORPORATION

Dates

Publication Date: 20260505
Application Date: 20210930

Claims (20)

1 . A first wireless communication device, the first wireless communication device comprising: a receiver configured to: receive, from a second wireless communication device, a first reservation signal that identifies one or more first resources that have been reserved by the second wireless communication device for data transmissions, the first reservation signal containing an indication of a first data priority level associated with the second wireless communication device data transmissions, and receive, from a third wireless communication device, a second reservation signal that identifies one or more second resources that have been reserved by the third wireless communication device for data transmissions, at least one of the identified second resources in the second reservation signal being the same as at least one of the identified first resources in the first reservation signal, the second reservation signal containing an indication of a second data priority level associated with the third wireless communication device data transmissions, the second data priority level being lower than the first data priority level; and a transmitter configured to transmit, to the third wireless communication device, a signal that indicates the one or more second resources are reserved by another wireless communication device such that the third wireless communication device reselects, based at least partially on the signal, one or more unused resources for data transmissions.
2 . The first wireless communication device of claim 1 , wherein the transmitter is further configured to transmit the signal before the one or more first resources that have been reserved by the second wireless communication device for data transmissions.
3 . The first wireless communication device of claim 2 , wherein the transmitter is further configured to transmit the signal an integer number of time-slots before the one or more first resources that have been reserved by the second wireless communication device for data transmissions.
4 . The first wireless communication device of claim 2 , wherein the transmitter is further configured to transmit the signal based, at least partially, on an estimated time required for the third wireless communication device to receive and decode the signal.
5 . The first wireless communication device of claim 1 , wherein the transmitter is further configured to transmit the signal in response to the first wireless communication device having no data to transmit beyond that contained in the signal.
6 . The first wireless communication device of claim 5 , wherein the transmitter is configured to transmit the signal in response to the first wireless communication device having no data to transmit beyond that contained in the signal, based on a network-configured data traffic condition threshold.
7 . The first wireless communication device of claim 1 , wherein the transmitter is further configured to transmit the signal in a second stage of a 2-stage Sidelink Control Information (SCI) transmission.
8 . The first wireless communication device of claim 7 , wherein the transmitter is further configured to modulate and encode the second stage of the 2-stage SCI transmission in accordance with a most robust modulation and coding scheme available to the first wireless communication device.
9 . The first wireless communication device of claim 7 , wherein the transmitter is further configured to modulate and encode the second stage of the 2-stage SCI transmission in accordance with a same modulation and coding scheme used to modulate and encode a first stage of the 2-stage SCI transmission.
10 . The first wireless communication device of claim 1 , wherein the transmitter is further configured to transmit the signal as a data transmission in a Physical Sidelink Shared Channel.
11 . A first wireless communication device, the first wireless communication device comprising: a transmitter configured to transmit, to a second wireless communication device, a first reservation signal that identifies one or more first resources that have been reserved by the first wireless communication device for data transmissions, the first reservation signal containing an indication of a first data priority level associated with the first wireless communication device data transmissions; a receiver configured to receive, from the second wireless communication device, a signal sent in response to a determination that at least one of the identified first resources in the first reservation signal is the same as one or more second resources identified in a second reservation signal received at the second wireless communication device from a third wireless communication device, the one or more identified second resources in the second reservation signal reserved by the third wireless communication device for data transmissions, the second reservation signal containing an indication of a second data priority level associated with the third wireless communication device data transmissions, the second data priority level being higher than the first data priority level, the signal indicating the one or more first resources are reserved by another wireless communication device; and a controller configured to reselect, based at least partially on the signal, one or more unused resources for data transmissions.
12 . The first wireless communication device of claim 11 , wherein the receiver is further configured to receive the signal in a second stage of a 2-stage Sidelink Control Information (SCI) transmission.
13 . The first wireless communication device of claim 12 , wherein the receiver is further configured to demodulate and decode the second stage of the 2-stage SCI transmission in accordance with a most robust modulation and coding scheme available to the first wireless communication device.
14 . The first wireless communication device of claim 12 , wherein the receiver is further configured to demodulate and decode the second stage of the 2-stage SCI transmission in accordance with a same modulation and coding scheme used to demodulate and decode a first stage of the 2-stage SCI transmission.
15 . A method performed at a first wireless communication device, the method comprising: receiving, from a second wireless communication device, a first reservation signal that identifies one or more first resources that have been reserved by the second wireless communication device for data transmissions, the first reservation signal containing an indication of a first data priority level associated with the second wireless communication device data transmissions; receiving, from a third wireless communication device, a second reservation signal that identifies one or more second resources that have been reserved by the third wireless communication device for data transmissions, at least one of the identified second resources in the second reservation signal being the same as at least one of the identified first resources in the first reservation signal, the second reservation signal containing an indication of a second data priority level associated with the third wireless communication device data transmissions, the second data priority level being lower than the first data priority level; and transmitting, to the third wireless communication device, a signal that indicates the one or more second resources are reserved by another wireless communication device such that the third wireless communication device reselects, based at least partially on the signal, one or more unused resources for data transmissions.
16 . The method of claim 15 , wherein transmitting the signal comprises transmitting the signal in response to the first wireless communication device having no data to transmit beyond that contained in the forwarded reservation signal.
17 . The method of claim 16 , wherein transmitting the signal comprises transmitting the signal in response to the first wireless communication device having no data to transmit beyond that contained in the forwarded reservation signal, based on a network-configured data traffic condition threshold.
18 . The method of claim 15 , wherein transmitting the signal comprises transmitting the signal in a second stage of a 2-stage Sidelink Control Information (SCI) transmission.
19 . The method of claim 18 , further comprising: modulating and encoding the second stage of the 2-stage SCI transmission in accordance with a most robust modulation and coding scheme available to the first wireless communication device.
20 . The method of claim 18 , further comprising: modulating and encoding the second stage of the 2-stage SCI transmission in accordance with a same modulation and coding scheme used to modulate and encode a first stage of the 2-stage SCI transmission.

Description

CLAIM OF PRIORITY The present application claims priority to Provisional Application No. 63/091,033, entitled “ENHANCED METHOD TO USE THE 2-STAGE SIDELINK CONTROL INFORMATION (SCI) DESIGN TO SUPPORT THE FORWARDING”, filed Oct. 13, 2020, which is assigned to the assignee hereof and hereby expressly incorporated by reference in its entirety. FIELD This invention generally relates to wireless communications and more particularly to vehicle-to-everything (V2X) communications between wireless communication devices. BACKGROUND A vehicle ad-hoc network (VANET) is an autonomously created wireless network of vehicles. In some VANETs, the wireless communication devices, which are located within the vehicles of the VANET, autonomously select the time-frequency resources for data transmissions to other vehicles within the VANET. However, if the number of transmitting vehicle-to-vehicle (V2V) devices is large with respect to the resources available for data transmissions, the probability of data transmission collisions is high. SUMMARY The methods and systems discussed herein describe a first wireless communication device receiving reservation signals from two other wireless communication devices, each reservation signal identifying one or more time-slots reserved for data transmissions and a data priority level associated with the data transmissions. When the first wireless communication device determines that the reservation signals have at least one common identified time-slot, the first wireless communication device transmits a forwarded reservation signal, which identifies the time-slots reserved by the wireless communication device with the higher data priority level, to the wireless communication device with a lower data priority level. The wireless communication device that receives the forwarded reservation signal determines whether to transmit data during the time-slots identified in the forwarded reservation signal. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a block diagram of an example of a system in which a plurality of wireless communication devices are nodes of a vehicle ad-hoc network (VANET). FIG. 1B is a block diagram of an example of a system in which the wireless communication devices of FIG. 1A are using reservation signal forwarding to avoid data transmission collisions in the VANET. FIG. 2A is a block diagram of an example of the base station shown in FIG. 1A. FIG. 2B is a block diagram of an example of a wireless communication device shown in FIG. 1A. FIG. 3 is a diagram of an example of a time-frequency space showing the reservation signals and the forwarded reservation signal that are transmitted in FIG. 1B. FIG. 4 is a flowchart of an example of a method in which a first wireless communication device receives first and second reservation signals from a second and third wireless communication device, respectively. Each reservation signal includes an indication of a data priority level and identifies one or more time-slots that have been reserved by the respective second and third wireless communication devices for data transmissions. At least one of the identified time-slots in the first reservation signal is the same as at least one of the identified time-slots in the second reservation signal. The second data priority level indicated in the second reservation signal is lower than the first data priority level indicated in the first reservation signal. The first wireless communication device transmits a forwarded reservation signal that identifies the one or more time-slots that have been reserved by the second wireless communication device. DETAILED DESCRIPTION The examples discussed below are generally directed to vehicle-to-vehicle (V2V) communication between two or more vehicles that are part of a vehicle ad-hoc network (VANET). However, any of the following examples may be applied to vehicle-to-everything (V2X) communication, which is the passing of information from a vehicle to any entity that may affect the vehicle or that the vehicle may affect. For example, V2X is a vehicular communication system that incorporates other, more specific types of communication, including V2V, V2I (vehicle-to-infrastructure), V2N (vehicle-to-network), V2P (vehicle-to-pedestrian), V2D (vehicle-to-device), and V2G (vehicle-to-grid). There are two types of V2X communication technology depending on the underlying technology being used: wireless local area network (WLAN)-based V2X, and cellular-based V2X (C-V2X). Some examples of V2X protocols include Long-Term Evolution (LTE) (Rel-14) V2X Mode 4 and 5G New Radio (NR) V2X Mode 2. In order to minimize the number of data transmission collisions in a VANET, a wireless communication device interested in transmitting data transmits a reservation signal, which is also referred to herein as a reservation channel transmission, which indicates resources to be used for the data transmission at a future time. The other wireless communication devices in the VANET recei