Abstract:
Systems and methods for a communication system including a set of transmitters, wherein operations of the set of transmitters are synchronized with an accuracy bound by a synchronization error. A controller forms a message with ordered symbols including data symbols and at least one identification symbol, and controls transmitters from the set of transmitters to transmit the message using a cyclic delay diversity (CDD). Wherein each transmitting transmitter prior to transmitting, circularly rotates the ordered symbols of the message with a unique shift, then copies some symbols located at an end of the message. Wherein a number of the copied symbols is based on a predetermined cyclic prefix length, into a first position in the rotated message, to form a transmitter identifiable message, and transmits via each transmitting transmitter the transmitter identifiable message.
Abstract:
Disclosed are methods and apparatus used in wireless communications. The methods and apparatus establish a codebook for use in sparse code multiple access (SCMA) encoded communications, in particular. The SCMA codebook is configured to set the codebook for at least one layer (i.e., a user) to include a constellation of points having a first grouping of constellation points located at first radial distance from an origin in a complex plane and a second grouping of constellation points located at a second radial distance from the origin. This codebook arrangement provides increased gains at receivers by optimizing the constellation shape to improve the distance between constellation points (i.e., SCMA codebook performance), and in particular more robust performance when encountering amplitude and phase misalignment in uplink (UL) multiple access.
Abstract:
A data processor selects a set of BOC correlations in accordance with a BOC correlation function for the sampling period if the primary amplitude exceeds or equals the secondary amplitude for the sampling period. The data processor selects a set of QBOC correlations in accordance with a QBOC correlation function for the sampling period if the secondary amplitude exceeds the primary amplitude for the sampling period. The data processor uses either the BOC correlation function or the QBOC correlation function, whichever with greater amplitude, at each sampling period for carrier tracking. Further, the data processor, through combining two sets of BOC correlations with different chip spacings provides an alternative unambiguous code acquisition of the received signal.
Abstract:
The current invention concerns a method and a device for generating a signal representing data. The method for generating a signal comprises modulating a portion (1P, 2P) of the data using phase shift keying and spreading the modulated portion over the at least one frequency base band using at least one highly auto-correlated spread code sequence (1C, 2C) associated with the frequency base band. The method for generating a signal is characterized by delaying, according to a delay determined using a remainder (1R, 2R) of the data (ID), the at least one spread code sequence (1C, 2C) by a time delay wherein the modulated portion (1MP, 2MP) is spread according the delayed spread code sequence (1DC, 2DC). This allows for additional bit rate through encoding of the data remainder in the delay.
Abstract:
A data processor selects a set of BOC correlations in accordance with a BOC correlation function for the sampling period if the primary amplitude exceeds or equals the secondary amplitude for the sampling period. The data processor selects a set of QBOC correlations in accordance with a QBOC correlation function for the sampling period if the secondary amplitude exceeds the primary amplitude for the sampling period. The data processor uses either the BOC correlation function or the QBOC correlation function, whichever with greater amplitude, at each sampling period to provide an aggregate correlation function that supports unambiguous code acquisition of the received signal.