Abstract: Carrier Interferometry (CI) codes include families of orthogonal polyphase codes that have no length restrictions and can be used for direct-sequence and multicarrier coding. Quasi-orthogonal CI channel codes simultaneously improve probability-of-error performance and increase throughput. CI filtering, which is based on CI codes, enables filtering and correlation operations via sampling and adding. CI codes simplify transform operations, such as Fourier transforms, by reducing or eliminating complex multiplications. CI filtering may be used to simplify synthesis and analysis functions and allow all physical-layer processing operations to be consolidated into simple sub-carrier selection and weighting operations. Thus, CI processing enables a software-defined baseband processor.

Abstract: Frequency-dependent cancellation separates a plurality of interfering signals received by a plurality of receivers. Received wideband single-carrier signals or multicarrier signals are separated into a plurality of narrowband subcarriers. Sub-carrier frequencies and frequency-band characteristics may be selected with respect to channel characteristics (e.g., coherence bandwidth, interference, etc.). A cancellation circuit provides complex weights to the sub-carrier components. Weighted components associated with each sub-carrier frequency are combined to separate a plurality of interfering signals. Optionally, a plurality of the separated subcarriers may be combined to reconstruct at least one transmitted single-carrier signal from a plurality of frequency components.

Abstract: A redundently modulated multicarrier protocol known as Carrier Interference Multiple Access (CIMA) is used in an optical-fiber network having wireless links at network nodes. CIMA is a protocol that can be used to create wireless protocols (such as TDMA and CDMA) having enhanced capacity and reduced system complexity. A CIMA optical-fiber network uses dispersion to enhance signal quality and facilitate switching. CIMA achieves both diversity benefits and capacity enhancements by providing redundancy in at least one diversity parameter while providing orthogonality in another diversity parameter. This basic operating principle of CIMA may be combined with multi-user detection to achieve frequency reuse and improved power efficiency. In the wireless link, diversity may be used to reduce the effects of small-scale fading on interferometry multiplexing.