Network congestion control with adaptive QoS bit-rate differentiation

Patent metadata

Field	Value
Publication number	US-9419906-B2
Application number	US-201114129365-A
Country	US
Kind code	B2
Filing date	Jul 5, 2011
Priority date	Jul 5, 2011
Publication date	Aug 16, 2016
Grant date	Aug 16, 2016

Abstract

A method is provided for congestion control in a network node ( 114; 510; 700; 900 ) of a communication network ( 701 ). The network node handles a plurality of data connections (DC 1-N ; RAB 1-N ) for conveying data between a first side and a second side of the communication network. The congestion control involves associating the data connections with respective target weights (w k ; k=1-N) for Quality-of-Service (QoS) bit-rate differentiation. The method comprises the following steps, performed in the network node. Experienced bit-rates (r k =1-N) are obtained ( 620 ) for the data connections (DC 1-N ; RAB 1-N). For each data connection (DC i ; RAB i), a time integrated difference is determined ( 632 ) between the data connection's targeted bit-rate according to its target weight (w i ), and its experienced bit-rate (r i ). Then, for each data connection, an adjusted weight (w′ i ) for QoS bit-rate differentiation is calculated ( 634 ) based on the determined time integrated difference and the target weight (w i ). The adjusted weights (w′ k ; k=1-N) are used for the congestion control of the data connections.

First claim

The invention claimed is:

1. A method for congestion control in a network node of a communication network, said network node being adapted to handle a plurality of data connections for conveying data between a first side and a second side of said communication network, wherein the congestion control involves associating the data connections with respective target weights for Quality-of-Service (QoS) bit-rate differentiation, the method comprising the steps, in said network node, of:
obtaining experienced bit-rates for the data connections;
for each data connection:
determining a time integrated difference between the data connection's targeted bit-rate according to its target weight, and its experienced bit-rate; and
calculating an adjusted weight for QoS bit-rate differentiation based on the determined time integrated difference and the target weight; and

using the adjusted weights for the congestion control of the data connections;
wherein calculating the adjusted weight for an individual data connection involves calculating a scaling factor v i (t) for said individual data connection at a time instant t as:

v
i

⁡

(
t
)

=

max
⁡

(

0
,

v
i

⁡

(

t
-
1

)

+

p
⁡

(

w
i

⁡

(
t
)

⁢

∑

k
=
1

N

⁢

⁢

r
k

⁡

(
t
)

∑

k
=
1

N

⁢

⁢

w
k

⁡

(
t
)

-

r
i

⁡

(
t
)

)

)

,

where p>0 is a settable parameter which determines a tradeoff between an ability to adapt to environmental changes in said communication network on the one hand, and reduced adaptation accuracy of small continuous variations on the other hand, where r k (t) is the experienced bit rate, and where w i (t) is the target for the individual data connection.

2. The method according to claim 1 , wherein the adjusted weight for an individual data connection is obtained by multiplying the calculated scaling factor v i (t) by the target weight for said individual data connection.

3. The method according to claim 1 , wherein the congestion control further comprises a congestion controlling action which involves:
detecting a condition indicative of a congestion for any of the data connections; selecting, among the data connections, a data connection for which a bit-rate reduction is to be caused; and
initiating the reduction of the bit-rate for the selected data connection.

4. The method according to claim 3 , wherein initiating the reduction of the bit-rate for the selected data connection involves causing discarding of a data packet on said selected data connection.

5. The method according to claim 4 , wherein the communication network is a transport network for a radio communication system, the network node is a radio base station, the plurality of data connections are radio access bearers, and the data packets are conveyed in the payload of protocol data units (PDU) in HS-DSCH data frames.

6. The method according to claim 3 , wherein detecting a condition indicative of a congestion for any of the data connections involves:
monitoring sequence numbers associated with incoming data packets, wherein said condition is triggered when the monitored sequence numbers indicate that data has been lost or received out of

Assignees

• Lundin Erik Geijer
• Lundin Leif
• Ericsson Telefon Ab L M

Inventors

• Lundin Erik Geijer

Classifications

• H04L47/25 Primary

  with rate being modified by the source upon detecting a change of network conditions · CPC title

• H04W28/0247 Primary

  based on conditions of the access network or the infrastructure network (central resource management H04W28/16) · CPC title

• H04L47/12

  Avoiding congestion; Recovering from congestion · CPC title

• H04L47/193

  at the transport layer, e.g. TCP related · CPC title

• H04L47/24

  Traffic characterised by specific attributes, e.g. priority or QoS · CPC title