METHOD FOR CHANNEL STATE MEASUREMENT IN MULTI-MODE MULTI-HOP WIRELESS NETWORKS

• US 20120195225A1
• Filed: 10/08/2010
• Published: 08/02/2012
• Est. Priority Date: 10/08/2009
• Status: Active Grant

• Current Assignee: InterDigital CE Patent Holdings SAS (InterDigital, Inc.)
• Original Assignee: Thomson Licensing (Vantiva SA)
• Inventors: Salonidis, Theodoros, Lundgren, Henrik, Towsley, Don, Subramanian, Anand Prabhu
• Granted Patent: US 9,125,097 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals

Abstract

The invention concerns a method for measuring channel state information of multiple transmission/reception modes in a wireless network comprising a plurality of nodes, said modes being defined by frequency channels and/or antenna patterns, said wireless network comprising a MAC (Media Access Control) layer and every node comprising at least one MAC queue, comprising the steps of: periodically sending broadcast probe packets by at least one node called transmitter node, using a pre-determined and globally known period and predetermined sequence of transmission modes, each of said probe packets containing the transmission mode used for its transmission a sequence number of the transmission mode in the pre-determined sequence of transmission modes and a timestamp value containing the time said broadcast probe packet was buffered at the MAC queue of the transmitter node; measuring, by at least one second node called receiving node receiving a broadcast probe packet, channel state information of a transmission/reception mode for the link between the transmitter node and the receiving node; storing, by said receiving node, said measured transmission/reception mode for said link; using information contained in said received broadcast probe packet, by said receiving node, to determine its reception mode and the beginning and end time instants it will use this reception mode, in order to receive a further broadcast probe packet and measure the next transmission mode of transmitter node, during a next measurement period of transmitter node.

Claims

1-14. -14. (canceled)

15. Method for measuring channel state information of multiple transmission/reception modes in a wireless network comprising a plurality of nodes, said transmission/reception modes being defined by frequency channels and/or antenna patterns, said wireless network comprising a MAC layer and each node comprising at least one MAC queue, comprising the steps of:

periodically receiving broadcast probe packets by at least one node called receiving node from at least one node, called a transmitter node, using a pre-determined and globally known period and predetermined and globally known sequence of transmission modes, each of said probe packets containing

(i) the transmission mode used for its transmission;

(ii) a sequence number of the transmission mode in the pre-determined sequence of transmission modes; and

(iii) a timestamp value containing the time at which said broadcast probe packet was buffered at the MAC queue of the transmitter node;

measuring, by the receiving node, channel state information of a transmission/reception mode for a link connecting the transmitter node and the receiving node;

storing, by said receiving node, said measured transmission/reception mode for said link;

using information contained in said received broadcast probe packet, by said receiving node, to determine

(i) the reception mode of said receiving node); and

(ii) the time during which said receiving node will use said reception mode in order to receive a further broadcast probe packet from said transmitter node during a next measurement period of transmitter node.

16. Method according to claim 15, wherein every node acts both as a receiving node and a transmitter node, transmitting a broadcast probe packet in a transmission mode and receiving at least one broadcast probe packet in at least one reception mode from its neighboring nodes during a measurement period.

17. Method according to claim 15, wherein a node can transmit at a single transmission mode or receive at a single reception mode at a time.

18. Method according to claim 15, wherein said channel state information is Received Signal Strength.

19. Method according to claim 15, wherein said channel state information is Signal-to-Noise ratio.

20. Method according to claim 15, wherein said transmitter node continuously executes successive measurement rounds, wherein each measurement round consists of M measurement periods, wherein each measurement period lasts TM time units and wherein, at the beginning of the m-th measurement period, a m-th broadcast probe packet is sent to a MAC protocol buffer.

21. Method according to claim 20, wherein, during a measurement period, said transmitter node broadcasts one probe packet after having switched to the corresponding transmission mode, and may receive one or more probe packets from other nodes while receiving in one or more different receiving modes.

22. Method according to claim 15, wherein, when a receiving node receives a broadcast probe packet, it computes a new start time for receiving in a next measurement period using a timestamp in the broadcast probe packet.

23. Method according to claim 22, wherein said receiving node computes its receiving duration for the next measurement period by computing broadcast probe packet transmission durations of its neighbor nodes, the delay for switching to receiving mode, a delay factor to account for MAC protocol delays, an estimate of the maximum clock phase difference between node and its neighbor nodes provided by the timestamps in the probe packets received by the neighbors of node and maximum propagation delay between node and its neighbor nodes.

24. Method according to claim 23, wherein said receiving node selects the receiving mode to be used in its receiving duration for the next measurement period using the transmission modes that its neighbor nodes will use during the next measurement period.

25. Method according to claim 24, wherein said receiving node selects the receiving mode according to specific criteria.

26. Method according to claim 25, wherein said receiving node selects the receiving mode that corresponds to the least recently received transmission/reception mode across its neighbor nodes.

27. Method according to claim 25, wherein said receiving node selects the least recently received transmission/reception mode across its neighbour nodes a limited number of consecutive times in order to avoid repeatedly selecting a non-functioning transmission/reception mode.

28. Method according to claim 24, wherein said receiving node sets a timer to schedule to switch to the selected receiving mode at the previously computed start time for the next measurement period of transmitter node.

29. Node comprising means for implementing the steps of the method for measuring channel state information according to claim 15.