Techniques for supporting harmonized co-existence of multiple co-located body area networks

• US 8,902,832 B2
• Filed: 08/07/2009
• Issued: 12/02/2014
• Est. Priority Date: 08/11/2008
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Patel, Maulin D., Chen, Richard
• Primary Examiner(s): Sinkantarakorn, Pao
• Assistant Examiner(s): CHANG, RICHARD K
• Application Number:
  US13/058,006
• Publication Number:
  US 20110268055A1
• Time in Patent Office: 1,943 Days
• Field of Search: 370/235, 370/311, 370/329, 370/350, 455/502
• US Class Current: 370/329
• CPC Class Codes: H04B 13/005 Transmission systems in which the medium consists of the human body
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 56/0015 one node acting as a reference for the others
• CPC Class Codes: H04W 56/0045 compensating for timing error by altering transmission time

Abstract

A method (400) for coordinating access to a wireless medium among multiple co-located body area networks (BANs). The method comprises detecting, by a master device of a first BAN, at least one alien BAN using beacons received from at least one co-located BAN, wherein an alien BAN is a BAN having its round start time (RST) misaligned with a RST of the first BAN (S410); recording a RST offset between the first BAN and the at least one alien BAN (S420); based on the RST offset determining which of the first BAN and the at least one alien BAN is an initiator BAN and which is a target BAN (S430); and realigning the RST of the initiator BAN with the RST of the target BAN (S460).

Claims

1. A method for coordinating access to a wireless medium among multiple co-located body area networks (BANs), each BAN including a plurality of slave devices and a plurality of master devices arranged in a two-tier architecture, the method comprising,

detecting, by a master device of a first BAN, at least one alien BAN using beacons received from at least one co-located BAN, wherein an alien BAN is a BAN where a round start time (RST) is misaligned with a RST of the first BAN;

recording a RST offset between the first BAN and the at least one alien BAN;

based on the RST offset, determining which of the first BAN and the at least one alien BAN is an initiator BAN and which is a target BAN; and

realigning, by all master devices belonging to the initiator BAN, the RST of the initiator BAN with the RST of the target BAN.

2. The method of claim 1, further comprising:

setting a realignment offset field, wherein the realignment offset field indicates a positive amount of time that all master devices in the initiator BAN delay their RSTs to align with a RST of the target BAN; and

setting a countdown variable to indicate a time when the realignment of the initiator BAN with the target BAN is triggered.

3. The method of claim 1, wherein the first BAN is determined to be the initiator BAN when a RST of the at least one alien BAN falls within the first half of a superframe of the first BAN.

4. The method of claim 1, wherein the RST is a start time of a round time, and wherein the time round includes a plurality of superframes and each superframe includes a plurality of time slots.

5. The method of claim 2, wherein the realignment offset field is included in a global beacon and transmitted to all master devices in the initiator BAN.

6. The method of claim 2, wherein the value of the countdown variable is identical for all master devices in the initiator BAN.

7. The method of claim 3, wherein an alien BAN with the largest RST offset is determined to be the target BAN, when multiple alien BANs were detected.

8. The method of claim 4, wherein one or more time slots are allocated for a global beacon period of a co-located BAN, and wherein during the global beacon period master devices of the co-located BAN transmit global beacons.

9. The method of claim 4, further comprising dividing time slots available for medium access reservation into time zones, wherein each BAN among the at least one co-located BAN owns a predetermined number of time slots.

10. The method of claim 8, wherein the realignment of the RSTs ensures at least synchronization among superframes of co-located BANs and non-overlapping among global beacon periods of co-located BANs.

11. The method of claim 9, wherein the realignment of the RSTs ensures non-overlapping between time zones owned by the initiator BAN and time zones owned by the at least one co-located BAN.

12. The method of claim 10, wherein global beacon periods of co-located BANs are separated by at least two superframes.

13. A method for coordinating access to a wireless medium among multiple co-located body area networks (BANs), the method comprising,

detecting, by a master device of a first BAN, at least one alien BAN using beacons received from at least one co-located BAN, wherein an alien BAN is a BAN where a round start time (RST) is misaligned with a RST of the first BAN;

recording a RST offset between the first BAN and the at least one alien BAN;

based on the RST offset, determining which of the first BAN and the at least one alien BAN is an initiator BAN and which is a target BAN; and

realigning the RST of the initiator BAN with the RST of the target BAN, wherein the RST is a start time of a round time, and wherein the time round includes a plurality of superframes and each superframe includes a plurality of time slots;

the method further comprising dividing time slots available for medium access reservation into time zones, wherein each BAN among the at least one co-located BAN owns a predetermined number of time slots, wherein the number of time zone reserved for a BAN is determined as follows;

14. The method of claim 13, wherein the number of reserved time zones for each BAN can be dynamically changed.

15. A non-transitory computer readable medium having stored thereon computer executable code, when executed, causing a processor to perform a process of coordinating access to a wireless medium among multiple co-located body area networks (BANs), each BAN including a plurality of slave devices and a plurality of master devices arranged in a two-tier architecture, the process comprising,

detecting, by a master device of a first BAN, at least one alien BAN using beacons received from at least one co-located BAN, wherein an alien BAN is a BAN where a round start time (RST) is misaligned with a RST of the first BAN;

recording a RST offset between the first BAN and the at least one alien BAN;

based on the RST offset, determining which of the first BAN and the at least one alien BAN is an initiator BAN and which is a target BAN; and

realigning, by all master devices belonging to the initiator BAN, the RST of the initiator BAN with the RST of the target BAN.