Method and arrangement in a telecommunications system
AssigneeTelefonaktiebolaget L M Ericsson (publ)
InventorsMiguel M. Lopez, Olof Liberg, Xun Qiu, Måarten Sundberg
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Abstract
Methods and arrangements are provided where signaling of the modulation type by means of rotation of the training sequence is provided. For each modulation type, a set of rotation angles is chosen. These sets have no element in common. New training sequences are generated by rotating one original training sequence. The rotation angle that minimizes the PAPR of the transmit signal can be chosen. At the receiver side, knowing the original training sequence, the receiver estimates blindly the rotation angle among the known possible rotation angles. The estimated rotation angle in the receiver maps to a unique modulation type.
Claims12
A method of transmitting a pre-coded Enhanced General Packet Radio Service (EPGRS)/EPGRS phase 2 (EGPRS2) symbol sequence, the symbol sequence comprising data sequence symbols and training sequence symbols, the method comprising:
- selecting a modulation method and a set of rotation angles corresponding to the selected modulation method, wherein sets of rotation angles corresponding to different modulation methods have no rotation angle in common, and wherein all the angles in said set of rotation angles are integer multiples of 2π divided by the total number of precoded data and training symbols;
- generating a set of training sequences from one original training sequence by rotating the original training sequence by the angles in said set of rotation angles;
- selecting a rotation angle from said set of rotation angles;
- and
- pre-coding and transmitting the EGPRS/EGPRS2 symbol sequence using the selected modulation method and rotating the training symbol sequence using the selected rotation angle.
A transmitter for transmitting a pre-coded Enhanced General Packet Radio Service (EPGRS)/EPGRS phase 2 (EGPRS2) symbol sequence, the symbol sequence comprising data sequence symbols and training sequence symbols, the transmitter comprising controller circuitry configured to:
- select a modulation method and a set of rotation angles corresponding to the selected modulation method, wherein sets of rotation angles corresponding to different modulation methods have no rotation angle in common, and wherein all the angles in said set of rotation angles are integer multiples of 2π divided by the total number of precoded data sequence and training sequence symbols;
- generate a set of training sequences from one original training sequence by rotating the original training sequence by the angles in said set of rotation angles;
- select a rotation angle from said set of rotation angles;
- and
- pre-code and transmit the EGPRS/EGPRS2 symbol sequence using the selected modulation method and rotating the training symbol sequence using the selected rotation angle.
A method of receiving a pre-coded Enhanced General Packet Radio Service (EPGRS)/EPGRS phase 2 (EGPRS2) symbol sequence, the symbol sequence comprising data sequence symbols and training sequence symbols, the method comprising:
- receiving a precoded EGPRS/EGPRS2 symbol sequence including a rotated training symbol sequence, the rotation of the training symbol sequence uniquely identifying the modulation method used for the received symbol sequence;
- and
- knowing the original, unrotated training symbol sequence, blindly detecting the received symbol sequence and determining the modulation method of the received symbol sequence by determining the rotation angle of the training symbol sequence;
- wherein said blindly detecting comprises blindly detecting rotation angles from sets of rotation angles corresponding to different modulation methods, wherein the sets of rotation angles corresponding to different modulation methods have no rotation angle in common, and wherein all angles in the sets are integer multiples of 2π divided by the total number of precoded data sequence and training sequence symbols.
A receiver for receiving a pre-coded Enhanced General Packet Radio Service (EPGRS)/EPGRS phase 2 (EGPRS2) symbol sequence, the symbol sequence comprising data sequence symbols and training sequence symbols, the receiver comprising controller circuitry configured to:
- receive a precoded EGPRS/EGPRS2 symbol sequence including a rotated training symbol sequence, the rotation of the training symbol sequence uniquely identifying the modulation method used for the received symbol sequence;
- and
- knowing the original, unrotated training symbol sequence, blindly detect the received symbol sequence and determine the modulation method of the received symbol sequence by determining the rotation angle of the training symbol sequence;
- wherein to blindly detect the received symbol sequence, the controller circuitry is configured to blindly detect rotation angles from sets of rotation angles corresponding to different modulation methods, wherein the sets of rotation angles corresponding to different modulation methods have no rotation angle in common, and wherein all angles in the sets that are integer multiples of 2π divided by the total number of precoded data sequence and training sequence symbols.
Dependencies are inferred from the claim text.