Method for synchronizing bluetooth packets
AssigneeNokia Corporation
InventorJukka Reunamaki
Life of this patent
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Abstract
In Bluethooth medium rate packets, the access code and the header are frequently modulated by Gausian Frequency Shift Keying, and the actual payload is phase-modulated by a differential Quadrature Phase Shift Keying or an 8-ary DQPSK scheme. Guard time and a synchronization sequence are placed between the header and the payload parts because of the need to change the modulation scheme and because of the ease in packet transfer. A sequence having a form of ABA is added to a Barker sequence having a form of BABBAAA for providing the synchronization sequence having the form of ABABABBAAA, where A and B are different states in a binary representation.
Claims20
A method for improving synchronization between one communication device and another communication device using a packet, wherein the packet comprises an access code, a header and a payload segment, and the access code comprises an N-symbol synchronization word for synchronization purposes, wherein the N-symbol synchronization word is a generalized Barker sequence either in a first form or a second form, wherein
- in the first form the generalized Barker sequence consists of a two-symbol part having a form of (BA) preceding an (N−2)-symbol part, and wherein
- in the second form the generalized Barker sequence consists of a two-symbol part having a form of (AB) following a different (N−2)-symbol part, and wherein A is different from B in a binary representation, said method comprising the step of:
- extending the synchronization word for providing an extended synchronization word of at least (N+3) symbols by
- adding at least a 3-symbol sequence having a form of ABA immediately preceding the N-symbol synchronization word when the generalized Barker sequence is in the first form, and
- adding said at least a 3-symbol sequence immediately following the N-symbol synchronization word when the generalized Barker sequence is in the second form.
A data structure embodied in an electronically readable medium for storage in at least one of a plurality of communication devices to allow said at least one communication device to synchronize with another of said plurality of communication devices using a packet, wherein the packet includes a synchronization word, and said data structure is used to correlate with the synchronization word in the packet for synchronization purpose, said data structure comprising:
- an N-symbol generalized Barker sequence, and
- an extension part comprising at least a 3-symbol sequence having a form of ABA, wherein A is a different state from B in a binary representation, and wherein the generalized Barker sequence is either in a first form or a second form, wherein
- in the first form the generalized Barker sequence consists of a two-symbol part having a form of (BA) preceding an (N−2)-symbol part, and wherein
- in the second form the generalized Barker sequence consists of a two-symbol part having a form of (AB) following a different (N−2)-symbol part;
- and wherein
- when the generalized Barker sequence is in the first form, the extension part is immediately preceding the generalized Barker sequence, and
- when the generalized Barker sequence is in the second form, the extension part is immediately following the generalized Barker sequence.
Dependencies are inferred from the claim text.