US 8,798,034 B2Granted

System and method for selecting a route based on link metrics incorporating channel bandwidth, spatial streams and/or guard interval in a multiple-input multiple-output (MIMO) network

AssigneeMotorola Solutions, Inc.

InventorsPankaj Aggarwal, Hrishikesh Gossain, Avinash Joshi, Manish Shukla

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Abstract

Systems and methods are provided for determining a link metric for a communication link along a path between a source node to a destination node is provided. A node can generate a link metric (LM) for the communication link between the particular node and next-hop node towards the destination node in the path based on a plurality of variables. The node can determine the LM for the communication link based on a plurality of variables including: bandwidth on the communication link, a number of spatial streams used to transmit over the communication link, and a guard interval used used to transmit over the communication link.

Claims13

Dependent claims

A method for selecting one of a plurality of paths between a source node and a destination node in an ad-hoc multi-hopping peer-to-peer wireless communications network with MIMO capability based on link metrics (LMs) for each of the paths, the method comprising:

selecting, at a source node, a first path from the plurality of possible paths to the destination node, wherein the first path comprises one or more communication links that wirelessly connect the source node to the destination node;
determining, at each node along the first path after each transmission on that communication link towards the next-hop node, a corresponding LM for each communication link between each particular node and next-hop node towards the destination node in the first path, wherein each LM is determined using an equation:
LM
=
t
s
⁢
{
mod_Fec
,
L
}
+
t
e
PCR
*
⁡
(
1
+
(
Nss
-
1
)
·
Ps
⁡
(
t
)
)
·
(
1
+
(
Nb
⁢
⁢
max
Nb
⁢
⁢
min
-
1
)
·
Pb
⁡
(
t
)
)
·
(
1
+
(
Ng
⁢
⁢
max
-
Ng
⁢
⁢
min
Ngu
)
·
Pg
⁡
(
t
)
)
wherein:
ts is a total transmission time including overhead as a function of modulation scheme (mod), forward error correction (Fec), and packet length (L),
te is time spent on backoffs,
PCR is packet completion rate,
Nss is a maximum number of spatial streams that are possible to use during transmissions,
Nbmax is a maximum channel bandwidth that is possible to use during transmission,
Nbmin is a minimum channel bandwidth that is possible to use during transmission,
Ngmax is a maximum symbol length that is possible to use during transmission;
Ngu is a symbol length indicative of the guard interval scheme was used for the last transmission,
Ngmin is a minimum symbol length that is possible to use during transmission;
Ps(t) is an exponentially weighted moving average of a scaling factor for the number of streams that have been used during recent transmissions,
Pb(t) is an exponentially weighted moving average of a scaling factor for the bandwidth usage during recent transmissions, and
Pg(t) is an exponentially weighted moving average of a scaling factor for the guard interval that has been used during recent transmissions;
and
summing, at the source node, the link metrics (LMs) for each communication link along the path to generate a path metric for the first path.

91 more elements

A method for determining a link metric for a communication link, the method comprising:

determining, at a particular node, a link metric (LM) for the communication link between the particular node and a next-hop node towards a destination node, wherein the link metric (LM) is determined using an equation:
LM
=
t
s
⁢
{
mod_Fec
,
L
}
+
t
e
PCR
*
⁡
(
1
+
(
Nss
-
1
)
·
Ps
⁡
(
t
)
)
·
(
1
+
(
Nb
⁢
⁢
max
Nb
⁢
⁢
min
-
1
)
·
Pb
⁡
(
t
)
)
·
(
1
+
(
Ng
⁢
⁢
max
-
Ng
⁢
⁢
min
Ngu
)
·
Pg
⁡
(
t
)
)
wherein:
ts is a total transmission time including overhead as a function of modulation scheme (mod), forward error correction (Fec), and packet length (L),
te is time spent on backoffs,
PCR is packet completion rate,
Nss is a maximum number of spatial streams that are possible to use during transmission,
Nbmax is a maximum channel bandwidth that is possible to use during transmission;
Nbmin is a minimum channel bandwidth that is possible to use during transmission;
Ngmax is a maximum symbol length that is possible to use during transmission;
Ngu is a symbol length indicative of the guard interval scheme was used for the last transmission;
Ngmin is a minimum symbol length that is possible to use during transmission;
Ps(t) is an exponentially weighted moving average of a scaling factor for the number of streams that have been used during recent transmissions;
Pb(t) is an exponentially weighted moving average of a scaling factor for the bandwidth usage during recent transmissions;
and
Pg(t) is an exponentially weighted moving average of a scaling factor for the guard interval that has been used during recent transmissions,
wherein a source node uses the determined LM in a path selection operation.

90 more elements

Dependencies are inferred from the claim text.