Abstract: System and methodologies are provided herein for multiuser scheduling in a multiple-input multiple-output (MIMO) communication system. Various aspects described herein facilitate full feedback scheduling, wherein multiuser scheduling is performed based on an antenna selection and signal quality feedback, such as signal-to-interference-plus-noise ratio (SINR) feedback, from respective users. Based on information received from respective users, independent information streams can be transmitted from respective transmit antennas to respective users with the highest signal quality. Receive antenna selection can also be employed to allow respective users to select a single receive antenna on which information is to be received. Additional aspects described herein facilitate quantized feedback scheduling, wherein scheduling is performed based on signal quality feedback that is quantized into a finite number of bits by respective users.

Abstract: Systems, methods, and computer-readable media for a fair and efficient channel allocation and spectrum sensing for cognitive transmission in wireless networks are presented herein. A base station can send a cognitive user device a request to sense an idle channel associated with a primary network, and in response to receiving a willingness indicator or an attribute from the cognitive user device and/or a number of idle channels associated with the primary network sensed by the cognitive user device, the base station can assign the cognitive user device to transmit data on the idle channel associated with the primary network.

Abstract: Cluster-based cooperative spectrum sensing is provided for cognitive radio systems. For each cluster of cognitive users, a cluster head is determined. Each cluster head collects energies of a reporting channel measured by the cognitive users within the cluster and decides whether a primary user is absent from a given spectrum. A common receiver then aggregates the cluster-level decisions made by the cluster heads, and makes a decision across multiple, or all of, the clusters whether the primary user is absent based on a fusion function of the cluster-level decisions. If the primary (licensed) user is absent, then secondary (unlicensed) users may utilize the spectrum.

Abstract: For cognitive radio systems, the transmit power of a cognitive radio device is controlled so that the cognitive, unlicensed radio device does not interfere with the use of a shared spectrum by a primary, licensed device. Controlling the transmit power includes determining a distance, or a function of the distance, between a primary transmitter of the primary device and the cognitive radio device based on sensing information from a spectrum sensing process. The maximum transmit power of the cognitive radio device is then dynamically controlled based on the distance, or the function of the distance, while considering a worst case scenario of an underlying cognitive radio model, to guarantee a quality of service requirement of the primary device.

Abstract: A full-rate distributed space-time (ST) code design is provided for amplify-and-forward cooperative wireless channels. A signal space diversity technique is employed at the source node and a unique signature vector at each relay node. The distributed space-time (ST) codes can achieve full cooperative diversity and full rate. The achievable diversity gain is M+1, where M is the number of relay nodes. Optimal power allocation can be used to maximize the coding gain under a total power constraint.

Abstract: For cognitive radio systems, the transmit power of a cognitive radio device is controlled so that the cognitive, unlicensed radio device does not interfere with the use of a shared spectrum by a primary, licensed device. Controlling the transmit power includes determining a distance, or a function of the distance, between a primary transmitter of the primary device and the cognitive radio device based on sensing information from a spectrum sensing process. The maximum transmit power of the cognitive radio device is then dynamically controlled based on the distance, or the function of the distance, while considering a worst case scenario of an underlying cognitive radio model, to guarantee a quality of service requirement of the primary device.

Abstract: User cooperation is an emerging transmission framework where users act as relays of each other to provide extra diversity paths for better overall performance. In various embodiments, systems and methods for transmitting data from a basestation to a mobile device in an adaptive communications network including user cooperation are provided. Among various embodiments, relaying is performed according to a time division duplex (TDD) system according to either a downlink-assisted relaying (DAR) which performs a relaying operation in a defined supplemental downlink timeslot or according to an uplink-assisted relaying (UAR) which performs a relaying operation in a defined supplemental uplink timeslot.

Abstract: For cognitive radio systems, the transmit power of a cognitive radio device is controlled so that the cognitive, unlicensed radio device does not interfere with the use of a shared spectrum by a primary, licensed device. Controlling the transmit power includes determining a distance, or a function of the distance, between a primary transmitter of the primary device and the cognitive radio device based on sensing information from a spectrum sensing process. The maximum transmit power of the cognitive radio device is then dynamically controlled based on the distance, or the function of the distance, while considering a worst case scenario of an underlying cognitive radio model, to guarantee a quality of service requirement of the primary device.

Abstract: For cognitive radio systems, the transmit power of a cognitive radio device is controlled so that the cognitive, unlicensed radio device does not interfere with the use of a shared spectrum by a primary, licensed device. Controlling the transmit power includes determining a distance, or a function of the distance, between a primary transmitter of the primary device and the cognitive radio device based on sensing information from a spectrum sensing process. The maximum transmit power of the cognitive radio device is then dynamically controlled based on the distance, or the function of the distance, while considering a worst case scenario of an underlying cognitive radio model, to guarantee a quality of service requirement of the primary device.

Abstract: Systems, methods, and computer-readable media for a fair and efficient channel allocation and spectrum sensing for cognitive transmission in wireless networks are presented herein. A base station can send a cognitive user device a request to sense an idle channel associated with a primary network, and in response to receiving a willingness indicator or an attribute from the cognitive user device and/or a number of idle channels associated with the primary network sensed by the cognitive user device, the base station can assign the cognitive user device to transmit data on the idle channel associated with the primary network.

Abstract: Cooperative concatenated coding techniques are provided for wireless communications between at least two users and a base station. A network system employing cooperative concatenated coding includes cooperating user devices each configured to encode and transmit at least a portion of a joint message. The joint message includes at least a portion of a first message from a first cooperating user device and at least a portion of a second message from a second cooperating user device. An embodiment includes encoding a first message from a first cooperating user, receiving a second message from a second cooperating user and decoding the second message. The methodology also includes re-encoding at least a portion of the decoded message with at least a portion of the first message to form a combined message, and then transmitting at least a portion of the combined message.

Abstract: Cooperative concatenated coding techniques are provided for wireless communications between at least two users and a base station. A network system employing cooperative concatenated coding includes cooperating user devices each configured to encode and transmit at least a portion of a joint message. The joint message includes at least a portion of a first message from a first cooperating user device and at least a portion of a second message from a second cooperating user device. An embodiment includes encoding a first message from a first cooperating user, receiving a second message from a second cooperating user and decoding the second message. The methodology also includes re-encoding at least a portion of the decoded message with at least a portion of the first message to form a combined message, and then transmitting at least a portion of the combined message.

Abstract: System and methodologies are provided herein for multiuser scheduling in a multiple-input multiple-output (MIMO) communication system. Various aspects described herein facilitate full feedback scheduling, wherein multiuser scheduling is performed based on an antenna selection and signal quality feedback, such as signal-to-interference-plus-noise ratio (SINR) feedback, from respective users. Based on information received from respective users, independent information streams can be transmitted from respective transmit antennas to respective users with the highest signal quality. Receive antenna selection can also be employed to allow respective users to select a single receive antenna on which information is to be received. Additional aspects described herein facilitate quantized feedback scheduling, wherein scheduling is performed based on signal quality feedback that is quantized into a finite number of bits by respective users.

Abstract: For cognitive radio systems, the transmit power of a cognitive radio device is controlled so that the cognitive, unlicensed radio device does not interfere with the use of a shared spectrum by a primary, licensed device. Controlling the transmit power includes determining a distance, or a function of the distance, between a primary transmitter of the primary device and the cognitive radio device based on sensing information from a spectrum sensing process. The maximum transmit power of the cognitive radio device is then dynamically controlled based on the distance, or the function of the distance, while considering a worst case scenario of an underlying cognitive radio model, to guarantee a quality of service requirement of the primary device.

Abstract: System and methodologies are provided herein for multiuser scheduling in a multiple-input multiple-output (MIMO) communication system. Various aspects described herein facilitate full feedback scheduling, wherein multiuser scheduling is performed based on an antenna selection and signal quality feedback, such as signal-to-interference-plus-noise ratio (SINR) feedback, from respective users. Based on information received from respective users, independent information streams can be transmitted from respective transmit antennas to respective users with the highest signal quality. Receive antenna selection can also be employed to allow respective users to select a single receive antenna on which information is to be received. Additional aspects described herein facilitate quantized feedback scheduling, wherein scheduling is performed based on signal quality feedback that is quantized into a finite number of bits by respective users.

Abstract: For cognitive radio systems, the transmit power of a cognitive radio device is controlled so that the cognitive, unlicensed radio device does not interfere with the use of a shared spectrum by a primary, licensed device. Controlling the transmit power includes determining a distance, or a function of the distance, between a primary transmitter of the primary device and the cognitive radio device based on sensing information from a spectrum sensing process. The maximum transmit power of the cognitive radio device is then dynamically controlled based on the distance, or the function of the distance, while considering a worst case scenario of an underlying cognitive radio model, to guarantee a quality of service requirement of the primary device.

Abstract: The disclosed subject matter relates to communicatively coupled cognitive radio systems, devices, methodologies, or combinations thereof, facilitating improved utilization of unused portions of spectral bands by secondary users generally allocated to other primary users. This improved utilization can be achieved by cooperative spectrum sensing employing ST coding and/or SF coding for transmit diversity. Further, cooperative spectrum sensing can be improved by employing relay diversity with or without algebraic coding. It is illustrated that a threshold probability of false alarm can be reduced by applying transmit diversity with space time coding and/or space frequency coding. It is further illustrated that relay diversity can be employed to compensate for reduced sensing diversity order were some nodes in a cooperative spectrum sensing system cannot report directly.

Abstract: The disclosed subject matter relates to communicatively coupled cognitive radio systems, devices, methodologies, or combinations thereof, facilitating improved utilization of unused portions of spectral bands by secondary users generally allocated to other primary users. This improved utilization can be achieved by cooperative spectrum sensing employing ST coding and/or SF coding for transmit diversity. Further, cooperative spectrum sensing can be improved by employing relay diversity with or without algebraic coding. It is illustrated that a threshold probability of false alarm can be reduced by applying transmit diversity with space time coding and/or space frequency coding. It is further illustrated that relay diversity can be employed to compensate for reduced sensing diversity order were some nodes in a cooperative spectrum sensing system cannot report directly.

Abstract: A full-rate distributed space-time (ST) code design is provided for amplify-and-forward cooperative wireless channels. A signal space diversity technique is employed at the source node and a unique signature vector at each relay node. The distributed space-time (ST) codes can achieve full cooperative diversity and full rate. The achievable diversity gain is M+1, where M is the number of relay nodes. Optimal power allocation can be used to maximize the coding gain under a total power constraint.

Abstract: Various embodiments of multi input multi output (MIMO) communication systems include a transmit Tomlinson-Harashima Precoding (THP) technique and a single carrier frequency domain equalization (SC-FDE) technique. Parallel THP-FDE and successive THP-FDE are proposed based on the minimum mean square error (MMSE) criterion. For the successive THP-FDE technique, where all transmit streams are subsequently precoded, both suboptimal and optimal MMSE ordering algorithm are set forth. Since the feedback processing is performed at the transmitter, no error propagation problem exists in the THP-FDE MIMO techniques, yielding significant performance improvements over conventional FDE MIMO techniques. Applying channel prediction and THP compensation techniques can also further enhance performance.