Method and system for multirate multiuser modulation
First Claim
1. Method for performing orthogonal multiple access, the method comprising the steps of:
- a first subscriber unit within a communication system being assigned a first set of subcarriers comprising a first number of subcarriers, wherein spacing between neighboring subcarriers within the first set of subcarriers is uniform, and wherein the first set of subcarriers are used for transmitting a first single-carrier symbol stream;
a second subscriber unit within the communication system being assigned a second set of subcarriers comprising a second number of subcarriers, wherein spacing between neighboring subcarriers within the second set of subcarriers is uniform and wherein the second set of subcarriers are used for transmitting a second single-carrier symbol stream;
wherein the first number of subcarriers differs from the second number of subcarriers;
wherein the first and the second set of subcarriers are assigned in an orthogonal fashion; and
wherein the first and the second set of subcarriers are used for frequency division multiple access between the first and the second subscriber units.
4 Assignments
0 Petitions
Accused Products
Abstract
A multi-rate interleaved frequency division multiple access (IFDMA) modulation scheme permits users to transmit at different data rates or to vary their data rates while providing frequency diversity and preserving low peak-to-average power ratios and orthogonality between user data rates. The modulation scheme allows user-specific data block and repetition sizes, as well as user-specific modulation codes. Code assignment rules are provided for maintaining orthogonality between the different user data rates. Block and phase ramp modulation codes can be used. Asynchronous transmissions by users are supported by ensuring that the length of the cyclic extension is sufficiently long to tolerate worst case relative signal arrival delays between users and the channel pulse response duration over the communication medium. The modulation scheme can be employed in wireless communication systems, such as cellular or paging systems.
-
Citations
22 Claims
-
1. Method for performing orthogonal multiple access, the method comprising the steps of:
-
a first subscriber unit within a communication system being assigned a first set of subcarriers comprising a first number of subcarriers, wherein spacing between neighboring subcarriers within the first set of subcarriers is uniform, and wherein the first set of subcarriers are used for transmitting a first single-carrier symbol stream; a second subscriber unit within the communication system being assigned a second set of subcarriers comprising a second number of subcarriers, wherein spacing between neighboring subcarriers within the second set of subcarriers is uniform and wherein the second set of subcarriers are used for transmitting a second single-carrier symbol stream; wherein the first number of subcarriers differs from the second number of subcarriers; wherein the first and the second set of subcarriers are assigned in an orthogonal fashion; and wherein the first and the second set of subcarriers are used for frequency division multiple access between the first and the second subscriber units. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. A method comprising the steps of:
-
a subscriber unit within a communication system receiving a subcarrier assignment; the subscriber unit generating a signal to be transmitted, wherein the signal comprises a first set of subcarriers corresponding to the received subcarrier assignment comprising a first number of subcarriers, wherein spacing between neighboring subcarriers within the first set of subcarriers is uniform, and wherein the first set of subcarriers are used for transmitting a single-carrier symbol stream; wherein the first number of subcarriers differs from a second number of subcarriers assigned to a second subscriber unit; wherein the first and the second set of subcarriers are assigned in an orthogonal fashion; wherein the first set of subcarriers are to be used for frequency division multiple access; and the subscriber unit transmitting the frequency division multiplexed signal. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
-
Specification