33results about How to "Reduce channel interference" patented technology

A circuit for reducing adjacent-channel interference by pre-linearizing and pre-distorting an input signal to be transmitted via a power amplifier having a non-linear transmission characteristic is disclosed. A portion of the input signal exceeding a dynamic range of the power amplifier is determined and expanded along the time axis to produce an expanded version thereof. The expanded version and the input signal are combined, such that the expanded version is subtracted from the input signal, to produce a pre-linearized signal. The circuit further has a pre-distorting unit for pre-distorting the pre-linearized signal using complex pre-distortion coefficients, such that the distortion introduced by the non-linear transmission characteristic of the power amplifier is substantially compensated for according to magnitude and phase.

A Next Generation Data Network is described. It leverages the “cloud” for data management, low frequency data computation and analytics. The wireless network is a single frequency network that permits limited non-line of sight operation. The wireless network using packet switched beams, the beams are formed and switched electronically. It utilizes advanced signal processing to compensate for low transmit signal power and multipath reflections that can be frequency or flat fades.

A method and apparatus are described including receiving, by a transmitter, a report from an associated client, setting and using a downlink transmit power level responsive to the report for data transmissions to the associated client, determining a downlink data loss rate and adjusting the downlink transmit power level responsive to the downlink data loss rate, wherein said report includes received signal strength, client transmit power level and one of link margin and receiver sensitivity. Also described are a method and apparatus including receiving, by a receiver, a request for a report, transmitting the requested report, receiving an instruction to use an uplink transmit power level, setting and using the uplink transmit power level, determining an uplink data loss rate and adjusting the uplink transmit power level responsive to the uplink data loss rate, wherein said report includes said received signal strength, client transmit power level and one of said link margin and said receiver sensitivity.

A method of radio control, adapted in a wireless device that includes a cognitive radio and a free radio. First, the cognitive radio scans within vicinity or range to receive frames sent from or to the free radio, for retrieving therefrom network information of on-air frames indicative of past operational status of the free radio. Next, network operation commands of the free radio are sensed by the cognitive radio, in which the network operations commands being indicative of present operational status of the free radio. Then, a step is performed using the cognitive radio to read network flags generated in the free radio indicative of future operational status of the free radio. Following operation of the cognitive radio is then configured based on at least one of the past, present and future operational status of the free radio so as to reduce channel interferences with the free radio

A Next Generation Data Network is described. It leverages the “cloud” for data management, low frequency data computation and analytics. The wireless network is a single frequency network that permits limited non-line of sight operation. The wireless network using packet switched beams, the beams are formed and switched electronically. It utilizes advanced signal processing to compensate for low transmit signal power and multipath reflections that can be frequency or flat fades.

A television receiver for receiving digital and analog signals that reduces adjacent channel interference when receiving digital signals susceptible to interference caused by a lower adjacent NTSC signal. Upon receiving the digital signal, the receiver heterodynes the digital signal with a local oscillator (LO) signal to produce an intermediate frequency (IF) signal. A microprocessor searches a memory unit for stored information regarding the digital broadcast channel and determines the presence or absence of a lower adjacent NTSC channel. In the case a lower adjacent NTSC channel is present, the microprocessor shifts the frequency of the LO signal causing the IF signal to shift towards the lower band edge of a surface acoustic wave (SAW) filter present in a digital signal processor further attenuating the lower adjacent NTSC channel.

The present invention relates to a wireless communication system. More particularly, the present invention relates to a method and apparatus which indicate, using multiple CQIs, channel quality in the event multiple users are scheduled in the same time / frequency area, and to a method and apparatus which estimate a channel state using said multiple CQIs. According to the embodiments of the present invention, a channel state can be estimated in a more accurate manner in a multi-user MIMO system.

An improved multicarrier modulation system and method is introduced which has the advantages of both isotropic orthogonal transfer algorithm orthogonal frequency division multiplexing (IOTA OFDM) and scalable advanced modulation (SAM). The invention reduces adjacent channel interference (ACI) in the multicarrier modulation system used in multicast systems by generating (2601) a spectrally efficient modified pulse for multicarrier modulation and then adapting (2605) the pulse at the edge of the subchannel for reducing the ACI product by the total multicarrier signal (2607). This BTRRC OFDM (2607) is an Offset OFDM with BTRRC pulse (2605) while the prior art RRC OFDM (604) is an Offset OFDM with RRC pulse (603). BTRRC OFDM has characteristics similar to RRC OFDM and has better power efficiency in simulcast or Nakagami fading environments where there is a timing error. Thus, BTRRC OFDM is desirable to substitute SAM in a simulcast environment.

According to one embodiment of the invention, a method for managing channels in a wireless network includes retrieving device parameters from a wireless network device communicating on a channel in the wireless network. The device parameters include a parameter indicative of a location of the wireless network device and a parameter indicative of the channel of the wireless network device. The channel is associated with a data transmission frequency. The method also includes generating a list of available channels for the wireless network device by determining a channel pattern in the wireless network. The method further includes specifying the channel on which the wireless network device should communicate based on the generated list of available channels to reduce channel interference to the wireless network device.

The present invention reduces adjacent channel interference for a wireless peripheral device. A direct digital synthesizer generates a waveform having intermediate angular changes during a transition time between symbol intervals. After the transition time, the direct digital synthesizer generates the waveform with an angular value that corresponds to the symbol being transmitted. In an exemplary embodiment, a generated waveform is characterized by one of two designated frequencies in response to a value of an input information bit. The waveform is further characterized by at least one intermediate frequency during a transition time between a change of the designated frequency. Another embodiment of the invention utilizes phase changes rather than frequency changes during reduce adjacent channel interference. With another aspect of the invention, methods are provided to determine waveform parameters for reducing adjacent channel power (ACP) to a maximum level of interference.

Base stations having potentially interfering terminal stations that are geographically located on the same or similar diagonal or Line of Sight (relative to the base station) operate on a first set of time frames (e.g., “even” time frames). Similarly, base stations having potentially interfering terminal stations that are not geographically located on the same or similar diagonals operate on a second set of time frames (e.g., “odd” time frames). By alternating in their use of the even and odd frames, the potential for co-channel interference between terminal stations is minimized. Systems and methods are disclosed which reduce co-channel and adjacent channel interference between terminal stations of different cells as well as adjacent channel interference between terminal stations of adjacent cells. The methods and systems so described can be used during the deployment or expansion of a communication system in a region.

A method of radio control, adapted in a wireless device that includes a cognitive radio and a free radio. First, the cognitive radio scans within vicinity or range to receive frames sent from or to the free radio, for retrieving therefrom network information of on-air frames indicative of past operational status of the free radio. Next, network operation commands of the free radio are sensed by the cognitive radio, in which the network operations commands being indicative of present operational status of the free radio. Then, a step is performed using the cognitive radio to read network flags generated in the free radio indicative of future operational status of the free radio. Following operation of the cognitive radio is then configured based on at least one of the past, present and future operational status of the free radio so as to reduce channel interferences with the free radio.

In a communication system and a communication method using a TDD-OFDMA communication method, inter-carrier interference due to delay dispersion is prevented by suppressing the delay time within a guard interval.In a base station device 10, based on a pilot symbol included in uplink information transmitted from a terminal device 20 through an assigned channel assigned by a channel assignment response, it is estimated whether a received timing of receiving the uplink information is early or late, the received timing estimation result is recorded in a timing recording unit, and when transmitting downlink information from the base station device 10, a transmission timing request is added to the downlink information based on content recorded in the timing recording unit and the downlink information is transmitted to the terminal device 20 (Step S15), and in the terminal device 20, the received transmission timing request is recorded in a transmission timing recording unit, and uplink information is transmitted from the terminal device 20 to the base station device 10 at a timing instructed by a transmission timing request (Step S16).

An improved multicarrier modulation system and method is introduced which has the advantages of both isotropic orthogonal transfer algorithm orthogonal frequency division multiplexing (IOTA OFDM) and scalable advanced modulation (SAM). The invention reduces adjacent channel interference (ACI) in the multicarrier modulation system used in multicast systems by generating (2601) a spectrally efficient modified pulse for multicarrier modulation and then adapting (2605) the pulse at the edge of the subchannel for reducing the ACI product by the total multicarrier signal (2607). This BTRRC OFDM (2607) is an Offset OFDM with BTRRC pulse (2605) while the prior art RRC OFDM (604) is an Offset OFDM with RRC pulse (603). BTRRC OFDM has characteristics similar to RRC OFDM and has better power efficiency in simulcast or Nakagami fading environments where there is a timing error. Thus, BTRRC OFDM is desirable to substitute SAM in a simulcast environment.

Selection between first and second communication channels of differing bandwidths for communication between communication devices may be chosen by a method, an apparatus, or a computer-readable medium wherein the first channel is employed as a communication channel, a determination is made whether a criterion associated with the communication channel is met, and, if the criterion associated with the communication channel is met, an evaluation of the second channel is performed and one of the first and second channels is chosen to subsequently employ as the communication channel based on the evaluation of the second channel.

The invention discloses a single-frequency network method base on orthogonal frequency division multiplexing technique, dissolving the problem that channel interference between sub-networks at the junction of the existing single frequency network area affects the network quality of the borders. The invention comprises the following steps: the invention undergoes unified resource planning about the single frequency network; the invention undergoes unified addressing about areas provided with service from the single frequency network so that adjacent areas have different network addresses; the invention synchronizes aerial signal of the single frequency network; the invention classifies a transmitter and a honeycomb in the single frequency network; the invention determines the best distance between the transmitters in the single frequency network; the invention deals with a control channel of the single frequency network related to area; the invention deals with a business channel of the single frequency network related to area. The single frequency network needs to undergo reasonable planning about regional service at the junction of different areas, reduces channel interference between systems in different areas and improves service quality of the single frequency network.

The disclosed embodiments relate to reducing adjacent channel interference in an OFDM receiver. An error metric is monitored and the carrier frequency of the desired channel is slowly adjusted in response to the error metric. In this manner, the received OFDM signal, including the desired signal corrupted by the adjacent interfering channel, may be shifted until the zero crossings of the adjacent channel line up with the FFT bins. A multi-tap equalizer may then be used to remove the inter-bin interference that results from the frequency offset in the desired channel.

The present invention relates to a wireless communication system. More particularly, the present invention relates to a method and apparatus which indicate, using multiple CQIs, channel quality in the event multiple users are scheduled in the same time / frequency area, and to a method and apparatus which estimate a channel state using said multiple CQIs. According to the embodiments of the present invention, a channel state can be estimated in a more accurate manner in a multi-user MIMO system.

The invention relates to a broadcast channel searching method and device, an equipment terminal and a storage medium, and the searching method comprises the steps: determining a target intermediate frequency signal corresponding to a current radio frequency point according to a plurality of preset intermediate frequency points, acquiring the signal average power of a target intermediate frequency signal corresponding to the current radio frequency point in a preset power spectrum window and the signal average power and the noise average power corresponding to the previous adjacent radio frequency point; calculating a difference value between the signal average power corresponding to the current radio frequency point and the signal average power corresponding to the previous adjacent radio frequency point, and judging whether the difference value is greater than a preset signal power threshold value or not; if yes, calculating an absolute value of a difference value between the signal average power corresponding to the current radio frequency point and the noise average power corresponding to the previous adjacent radio frequency point, and judging whether the absolute value of the difference value is smaller than a preset noise power threshold value or not; and if yes, taking the broadcast channel corresponding to the current radio frequency point as the target broadcast frequency. According to the searching method, the channel quality of the searched target broadcast channel is improved.

A vehicle to everything (V2X) mesh network system supporting a mobility operation of a production factory includes a road side unit (RSU) which is disposed in plural in the production factory, and connects infra-to-infra (I2I) wireless communication with an infrastructure facility, and connects vehicle-to-infra (V2I) wireless communication with an on board unit (OBU) mounted on an autonomous driving vehicle to form a V2X mesh network; and a control server controlling operation states of the RSU and the vehicle through the V2X mesh network.

The present invention provides a channel allocation method in D2D communication where an unlicensed frequency band and WiFi coexist. The method mainly includes: clustering the D2D-U devices coexisting with WiFi based on the distance, assigning a cluster head to each cluster, and the cluster head of each cluster according to the monitoring results of the surrounding spectrum environment by the D2D-U device members in the cluster, Dynamically select the currently used channel of its cluster, and the cluster head uses a competition mechanism to obtain the right to use the currently used channel on behalf of its cluster, and allocates the resources of the currently used channel to each D2D-U device in the cluster for use. The present invention aims at the randomness of WiFi AP positions and WiFi AP working channels. By dividing D2D-U devices into several disjoint clusters, and dynamically adjusting the working channels in the clusters according to the spectrum environment, not only makes full use of the idle spectrum At the same time, it can reduce the channel interference between D2D-U devices and between D2D-U devices and WiFi users, and improve the performance of communication links as much as possible.

The invention discloses a multi-user MAC channel access method based on a hopping pattern. Based upon an indoor visible light communication system with few user nodes and a small network coverage range, a reliable, high-speed and real-time channel access method is provided. Hardware upon which an MAC layer access scheme of a hopping pattern concept proposed by the invention is based is implementedconveniently, and can be implemented by using an existing commercial component, and the hopping pattern control can be implemented by software, so the cost is low and the method has a commercial value; the hopping pattern concept proposed by the invention can support illumination and communication dual functions; for requirements (not only is indoor illumination met, but a communication functionis also achieved) of the indoor visible light communication system, the method has a practical value and can be applied to production; the multi-user MAC channel access method is proposed based on characteristics of an indoor visible light communication system network; and the hopping pattern reduces channel interference between adjacent network APs when a terminal initially establishes channel access, so an RTS / CTS handshaking protocol is replaced, the access procedures are simplified, and the multi-user MAC channel access method has the feasibility and the effectiveness.

The invention discloses a multi-user MAC channel access method based on a hopping pattern, which provides a reliable, high-speed, and real-time channel access method for an indoor visible light communication system with few user nodes and a small network coverage. The hardware implementation based on the MAC layer access solution of the pattern concept is relatively convenient, and can be implemented by using existing commercial components. The hopping pattern control can be realized through software, which is low in cost and has commercial value. The hopping pattern concept proposed by the present invention can support dual functions of lighting and communication, and has practical value for the requirements of indoor visible light communication systems (meeting both indoor lighting and communication functions), and can be applied in production. The present invention is proposed for the characteristics of the indoor visible light communication system network. The hopping pattern reduces the channel interference of the adjacent network access point AP when the terminal first establishes channel access, replaces the RTS / CTS handshake protocol, simplifies the access process, and has the advantages of Feasibility and effectiveness.

A receiving device and method using a single RF chain includes a reception antenna module radiating a plurality of orthogonal beam patterns to receive a signal, a single RF chain processing a reception signal from the reception antenna module, a signal component extracting unit extracting a reception signal component corresponding to each beam pattern using the reception signal received through the reception antenna module and the single RF chain and a code value previously allocated to the plurality of beam patterns, and a beam pattern controller controlling a beam pattern radiated by the reception antenna module.