# US 10,455,604 B2 · Regret benefit ratio link scheduler for wireless backhaul with directional antennas

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- Number: US 10,455,604 B2
- Document ID: US10455604B2
- Status: Granted
- Kind: B2
- Application number: 15/865,568
- Filed: 2018-01-09
- Published: 2018-07-19
- Granted: 2019-10-22
- Earliest claimed: 2017-01-16
- Assignees: University of Florida Research Foundation, Inc.
- Applicants: University of Florida Research Foundation, Incorporated
- Inventors: Dapeng Oliver Wu; Yun Zhu; Jiade Li; Qiuyuan Huang
- Web page: https://patentgrep.com/patent/US10455604B2

## CPC

- H04W 72/54: based on quality criteria
- H04W 72/12: Wireless traffic scheduling
- H04W 72/566: of the information or information source or recipient
- H04W 72/569: {of the traffic information}
- H04B 7/024: Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
- H04W 72/046: {the resource being in the space domain, e.g. beams}
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- H04B: TRANSMISSION

## Abstract

A wireless system can include a plurality of directional antennas and a scheduler scheduling multiple links between the plurality of directional antennas. The scheduler can schedule the multiple links concurrently in the same time slot based on Regret Benefit Ratio (RBR). The RBR is a single indicator combining contention for one of the directional antennas and Quality of Service (QoS). The scheduler can introduce a contention graph for the directional antennas that capture a global knowledge of interference.

## Claims

### Claim 1

A wireless system, comprising:
a plurality of directional antennas; and
a scheduler for scheduling multiple links between the plurality of directional antennas,
wherein the scheduler schedules the multiple links concurrently in a same time slot based on a plurality of Regret Benefit Ratios (RBRs), wherein each RBR of the plurality of RBRs is associated with a link of the multiple links, wherein each RBR of the plurality of RBRs is a single ratio calculated based on contention between a link of the multiple links and contended neighbors of the link and a Quality of Service (QoS) of the link, and wherein contention between the link and contended neighbors of the link is determined based at least in part on a count of the contended neighbors.

### Claim 2 (depends on 1)

The wireless system according to claim 1, wherein the contended neighbors of the link comprise one or more links that cause interference to the link at a level higher than a threshold under concurrent transmissions.

### Claim 3 (depends on 1)

The wireless system according to claim 1, wherein the scheduler consults a contention graph for the plurality of directional antennas, and wherein the contention graph comprises a global knowledge of interference.

### Claim 4 (depends on 1)

The wireless system according to claim 1, wherein the scheduler assigns a priority to each link of the multiple links based on a QoS requirement for the link.

### Claim 5 (depends on 4)

The wireless system according to claim 4, wherein the scheduler assigns the priority as an inverse of a number of slots that a link needs in a channel time allocation period (CTAP) to achieve a QoS requirement for the link.

### Claim 6 (depends on 1)

The wireless system according to claim 1, wherein the scheduler calculates each RBR of the plurality of RBRs by using a contention graph for the plurality of directional antennas and a priority for each link of the multiple links.

### Claim 7 (depends on 6)

The wireless system according to claim 6, wherein an RBR of a link v is expressed as the following Formula 1:
r
v
=
∑
i
⁢
⁢
ϵ
⁢
⁢
N
G
⁡
(
v
)
⁢
P
i
P
v
Formula
⁢
⁢
1
where, rv is the RBR of link v, NG(v) is a neighbor set of link v, and Pv is a priority of link v.

### Claim 8 (depends on 7)

The wireless system according to claim 7, wherein the scheduler selects a link from the contention graph to add to a scheduling set and removes an unqualified link from the contention graph.

### Claim 9 (depends on 8)

The wireless system according to claim 8, wherein the unqualified link satisfies one or more of that it has achieved a QoS requirement for the unqualified link, that it has been scheduled and is currently ongoing, or that it is a neighbor of an ongoing link.

### Claim 10 (depends on 9)

The wireless system according to claim 9, wherein the scheduler iteratively selects a link with a smallest RBR from the contention graph and adds the selected link to the scheduling set.

### Claim 11 (depends on 10)

The wireless system according to claim 10, wherein the scheduler divides a slot into a number of stages.

### Claim 12 (depends on 11)

The wireless system according to claim 11, wherein an end of the number of stages is a finished slot in which a scheduling link achieves a QoS requirement for the scheduling link.

### Claim 13

A distributed network system, comprising;
a pair of directional antennas facing each other and providing a link configured to transmit data from a source to a destination;
a beacon coordinating the pair of directional antennas; and
a scheduler adjusting a back-off window for the link based on a Regret Benefit Ratio (RBR) for the link, wherein the RBR for the link is determined based at least in part on a Quality of Service (QoS) for the link and a number of contended neighbors of the link.

### Claim 14 (depends on 13)

The distributed network system according to claim 13, wherein the RBR is expressed as the following Formula 2:
C
⁢
⁢
W
∝
R
⁢
⁢
B
⁢
⁢
R
=
regret
benefit
,
Formula
⁢
⁢
2
where benefit is a Quality of Service (QoS), regret is a number of contended neighbors, and CW is a contention window.

### Claim 15 (depends on 14)

The distributed network system according to claim 14, wherein the scheduler initializes a random back-off window size within a minimum contention window size (CWmin) and a maximum contention window size (CWmax), wherein the CWmin and the CWmax are parameters of a priority level associated with the source.

### Claim 16 (depends on 15)

The distributed network system according to claim 15, wherein the scheduler adjusts CWmin and CWmax such that a probability that a randomized back-off window size of a given priority level i overlaps with that of priority level j (j≠i) is reduced to minimum.

### Claim 17 (depends on 14)

The distributed network system according to claim 14, wherein the scheduler maps the RBR to the CW by using a two-phase process.

### Claim 18 (depends on 13)

The distributed network system according to claim 13, wherein the number of contended neighbors is determined using a beacon signal periodically broadcasted by the beacon.

### Claim 19 (depends on 18)

The distributed network system according to claim 18, further comprising an omni-directional antenna for the beacon.

### Claim 20 (depends on 19)

The distributed network system according to claim 19, wherein the scheduler schedules the link according to a base station's contention level that is proportional to the number of contended neighbors.