Transmit diversity framing structure for multipath channels
First Claim
1. A method of transmitting dual signal-unit pairs from diverse antennas, comprising a) deriving a first N-point signal unit from a first portion of source data, and deriving a second N-point signal unit from a second portion of source data, b) processing in the time domain to i) establish a complex conjugated and modulo-N time-inverted form of the first N-point signal unit as a first variant signal unit, ii) establish a negative complex conjugated and modulo-N time-inverted form of the second N-point signal unit as a second variant signal unit, and iii) prepend a corresponding cyclic prefix on each signal unit to form a prefixed first signal unit, a prefixed first variant signal unit, a prefixed second signal unit, and a prefixed second variant signal unit;
- c) transmitting, substantially concurrently, the prefixed first signal unit from a first antenna and the prefixed second variant signal unit from a second antenna, and d) transmitting, substantially concurrently, the prefixed second signal unit from the first antenna and the prefixed first variant signal unit from the second antenna.
3 Assignments
0 Petitions
Accused Products
Abstract
Systems and techniques are disclosed for framing and processing single-carrier and/or OFDM transmit-diversity transmissions through delay-spread channels, as well as for deframing and processing the corresponding merged signals, received from a plurality of antennas, to estimate the transmitted information. Time-domain processing techniques may be used for both types of transmissions to create multiplexed dual signal-unit pairs, particularly when cyclic prefixes are needed to reduce delay-spreading effects. Repetitive pilot words may be employed in burst preambles and/or in payloads of transmission bursts to minimize or provide flexibility in the amount of bandwidth that is consumed to generate good channel response estimates under changing channel conditions.
182 Citations
60 Claims
-
1. A method of transmitting dual signal-unit pairs from diverse antennas, comprising
a) deriving a first N-point signal unit from a first portion of source data, and deriving a second N-point signal unit from a second portion of source data, b) processing in the time domain to i) establish a complex conjugated and modulo-N time-inverted form of the first N-point signal unit as a first variant signal unit, ii) establish a negative complex conjugated and modulo-N time-inverted form of the second N-point signal unit as a second variant signal unit, and iii) prepend a corresponding cyclic prefix on each signal unit to form a prefixed first signal unit, a prefixed first variant signal unit, a prefixed second signal unit, and a prefixed second variant signal unit; -
c) transmitting, substantially concurrently, the prefixed first signal unit from a first antenna and the prefixed second variant signal unit from a second antenna, and d) transmitting, substantially concurrently, the prefixed second signal unit from the first antenna and the prefixed first variant signal unit from the second antenna. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
-
-
19. A method of interpreting signals received by a receiver that were transmitted in multiplexed forms from diverse transmit antennas, the method comprising:
-
a) identifying a received pilot word that includes a first M-point pilot signal unit preceded by a cyclic prefix corresponding thereto, and a second M-point pilot signal unit preceded by a cyclic prefix corresponding thereto;
b) determining i) a first pilot received signal unit PR0 by using the first M-point pilot signal unit, after discarding the corresponding cyclic prefix, and ii) a second pilot received signal unit PR1 by using the second M-point pilot signal unit, after discarding the corresponding cyclic prefix;
c) producing i) a first channel estimate H˜
0 of a first channel response H0 by combining forms of PR0 and PR1 in a first manner with forms of corresponding expected pilot signal units ES0 and ES1, andii) a second channel estimate H˜
1 of a second channel response H1 by combining forms of PR0 and PR1 in a different second manner with forms of ES0 and ES1;
d) receiving a payload element that includes a first L-point received payload signal unit R0 and a second received payload signal unit R1;
e) combining forms of H˜
0 and H˜
1 with forms of R0 and R1 to obtain a first L-point combined signal unit C0 and a second L-point combined signal unit C1; and
f) deriving, from C0 and C1, estimates S˜
0 and S˜
1 of L-point transmitted payload signal units S0 and S1. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
-
-
34. A method of transmitting dual signal-unit pairs from diverse antennas, comprising:
-
a) deriving a first M-point pilot signal unit from a first portion of pilot data expected by a receiver, and deriving a second M-point pilot signal unit from a second portion of pilot data expected by the receiver;
b) establishing a complex conjugated form of the first pilot signal unit as a first variant pilot signal unit, and a negative complex conjugated form of the second pilot signal unit as a second variant pilot signal unit;
c) prependiing a corresponding cyclic prefix on each of the pilot signal units of steps (a) and (b) to form a prefixed first pilot signal unit, a prefixed second pilot signal unit, a prefixed first variant pilot signal unit, and a prefixed second variant pilot signal unit;
d) transmitting, substantially concurrently, the prefixed first pilot signal unit from a first antenna and the prefixed second variant pilot signal unit from a second antenna;
e) transmitting, substantially concurrently, the prefixed second pilot signal unit from the first antenna and the prefixed first variant pilot signal unit from the second antenna;
f) transmitting a repetitive pilot signal unit without a preamble, where J and/or P is an integer greater than 1, by i) transmitting, (J−
1) times immediately subsequent to step (d), the first pilot signal unit from a first antenna and the second variant pilot signal unit substantially concurrently from a second antenna, andii) transmitting, (P−
1) times immediately subsequent to step (e), the second pilot signal unit from the first antenna and the first variant pilot signal unit substantially concurrently from the second antenna. - View Dependent Claims (35, 36)
-
-
37. A system for transmitting dual signal-unit pairs from diverse antennas, comprising
a) first and second antennas; -
b) a signal-unit derivation block configured to derive N-point signal-units of time-domain samples from modulated source information;
c) a diversity multiplexer block configured to multiplex pairs of the derived N-point signal units into multiplexed dual signal-unit pairs, each multiplexed dual signal-unit pair including a first and a second N-pdint multiplexed-signal-unit (“
MSU”
) for the first antenna and a first and a second N-point MSU for the second antenna, wherein;
i) the first N-point MSU for the first antenna is related to the second N-point MSU for the second antenna by complex conjugation and modulo-N sample time inversion, and ii) the second N-point MSU for the first antenna is related to the first N-point MSU for the second antenna by complex conjugation, negation, and modulo-N sample time inversion;
d) a first output processing block configured to cyclically prefix the first and second N-point MSUs for the first antenna, and to process the prefixed MSUs for sequential transmission from the first antenna; and
e) a second output processing block configured to cyclically prefix the first and second N-point MSUs for the second antenna, and to process the prefixed MSUs for sequential transmission from the second antenna substantially concurrently with the sequential transmission from the first antenna. - View Dependent Claims (38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50)
-
-
51. A receiver system for receiving paired multiplexed signals transmitted from plural antennas, the system comprising:
-
a) a receive and alignment block configured to receive and align prefixed multiplexed-signal-units (“
MSUs”
) received sequentially in a frame structure having a preamble portion and a payload portion;
b) a cyclic prefix removal block configured to remove cyclic prefixes from received MSUs;
c) a pilot word identification block configured to identify, in accordance with relative position within the frame structure, J concatenated copies of a first received pilot MSU, RP0, followed by P concatenated copies of a second received pilot MSU, RP1, that were transmitted based upon a first expected pilot signal-unit EP0 and a second expected pilot signal-unit EP1; and
d) a channel estimation block configured to combine a representation of RP0 and a representation of RP1 with complex conjugated forms of EP0 and EP1 to create a first channel estimate H1, and to combine the representations of RP0 and RP1 with forms of EP0 and EP1 that are not complex conjugated to create a second channel estimate HE2. - View Dependent Claims (52, 53, 54, 55, 56, 57, 58, 59, 60)
-
Specification