443 results about "Channel assessment" patented technology

A method of controlling operation of a wireless device configured in a zero intermediate frequency architecture including a DC loop and a gain loop. The method includes processing energy in a wireless medium to generate a corresponding receive signal, monitoring the receive signal via a predetermined measurement window, detecting a changed condition in the channel, holding the gain feedback control loop at a constant gain level, and operating the DC loop in an attempt to search a stable DC value for the receive signal while the gain loop is held constant. A first case is DC saturation, where the gain is held constant until DC is controlled. A second case is clear channel assessment, where a prior stored gain setting is applied to the gain loop after detecting the end of the packet. A third case is preparation for receiving an expected acknowledgement packet after transmitting a packet, where again a prior stored gain setting is applied to the gain loop and DC is searched.

Methods (300) and corresponding systems (100) for adapting a clear channel assessment (CCA) threshold in a node in a wireless network includes determining a first successful transmission rate of the node and neighboring nodes in the wireless network when the node is set to use a first CCA threshold. Next, a second successful transmission rate of the node and the neighboring nodes is determined when the node is set to use a second CCA threshold. Thereafter, one of the first and the second CCA thresholds is selected based upon the first and second successful transmission rates. The determining a successful transmission rate of the node and neighboring nodes can include counting successful packet indications transmitted by the node and received by the node from the neighboring nodes. Transmitted successful packet indications can include transmitted acknowledgement messages.

A process, system, and apparatus are disclosed for mitigating access point data rate degradation with respect to a wireless communication between a wireless access point and a wireless client device. A channel assessment module is configured to assess the wireless communications, including interference signals, present on available wireless communications channels. The channel assessment module may establish quality parameters that at least partially describe the wireless communications quality of a given channel. A channel selection module is configured to select a best wireless communications channel based on the communications channel assessment. A channel connection module is configured to facilitate wireless communication between the wireless access point and the wireless client device on the best wireless communications channel.

Provided is a method for transmitting, by a transmitter, a first data having periodicity through a channel of an unlicensed band:

The transmitter adjusts at least one of transmission timing of the first data and clear channel assessment (CCA) timing for the channel to occupy the channel. The transmitter determines whether the channel may be occupied by performing a CCA on the channel at the CCA timing. The transmitter transmits the first data through the channel at the transmission timing of the first data, when it is determined that the channel may be occupied.

A system and method for classifying channels in a frequency hopping wireless communication system is provided. A data collection engine operates to obtain channel metrics indicating the level of interference for each channel used by the wireless communication system. A data analysis engine operates to provide a channel map for adaptive frequency hopping (AFH) and/or a channel map for channel avoidance. More specifically, the data analysis engine first operates to filter the channel metrics to remove channel metrics indicative of frequency hopping interference. Next, the channels are divided into a number of channel blocks each including at least two adjacent channels. For each channel block, the channel metrics of the channels within the channel block are combined to provide a metric sum. The data analysis engine then operates to classify each channel as usable or unusable based on the metric sums for each of the channel blocks.

Methods and apparatus for processing Physical layer Protocol Data Unit (PPDU) based on Basic Service Set (BSS) identification information in a High Efficiency WLAN (HEW) are described. An embodiment is a method for processing a PPDU by a station (STA) in a wireless local area network. The method may include determining whether the PPDU is transmitted from a different Basic Service Set (BSS) from a BSS to which the STA belongs or a same BSS as the BSS to which the STA belongs; and processing the PPDU using a first type of Clear Channel Assessment (CCA) threshold when the PPDU is determined to be transmitted from the different BSS, wherein the first type of CCA threshold is greater than a second type of CCA threshold which is used when the PPDU is determined to be transmitted from the same BSS.

Dynamic wireless channel selection and protocol control for streaming video utilizing transmission delay/packet loss information and channel utilization statistics. A transmission delay and packet loss monitor generates transmission delay information during the transmission of a video stream to remote wireless device(s) over a first wireless channel by timestamping and monitoring video packet(s) and associated transmission acknowledgement(s). The transmission delay information is compared to a predetermined threshold (e.g., a maximum tolerated delay threshold and/or total packet loss threshold) and, if the threshold is exceeded, a second wireless channel is selected for continued transmission of the video stream. In one mode, channel utilization statistics are likewise examined prior to a channel relocation event. Selection of the second wireless channel may be accomplished through a random or semi-random channel selection process, or through active scanning to collect clear channel assessment statistics for candidate channels. In another mode, at least one transmission protocol parameter is altered in response to a violation of one or more of the predetermined thresholds.

Disclosed are operation method of station in wireless local area network. An operation method comprises setting transmission power of a frame; setting a clear channel assessment (CCA) threshold based on a difference between the set transmission power and a default value of the transmission power; and performing a CCA operation based on the set CCA threshold. Therefore, performance of WLAN can be enhanced.

Techniques are described for channel access in a radio frequency spectrum band shared by a number of asynchronous operators. One or more clear channel assessment (CCA) procedures may be used to contend for one or more transmission periods in the radio frequency spectrum band. When the contention is won for one or more transmission periods, a determination may be made as to whether the a number of transmission periods for which contention has been won is equal to or greater than a threshold number of consecutive transmission periods. If the number of transmission periods for which contention has been won is at or above the threshold number, occupancy of the radio frequency spectrum band may be relinquished for a period of time, in order to allow another operator to access the radio frequency spectrum band.

A method to adjust either the detection sensitivity threshold (e.g., the clear channel assessment (CCA) for an 802.11 complaint wireless transceiver) and/or the receiver communication sensitivity threshold (e.g., the start of packet (SOP) for an 802.11 complaint wireless transceiver) to improve performance in a wireless networking environment, such as a high density environment. Both the detection cell and the communication cell can be set equal to each other or the detection cell and communication cell can be independently set. There are also described herein techniques for determining detection cell. Also described herein are techniques for determining communication cell. The present invention includes apparatuses configured to implement a method and/or technique described herein.

Channel state indication signals are transmitted to communication stations via wireless channels and SINR (Signal to Interference and Noise Ratio) values of the channel state indications signals or channel environment parameters according to the SINR values are received from the communication stations as feedback signals. A channel estimation apparatus includes: an average measurement unit for measuring average values of the feedback signals over a period of time, each of the average values being an average value of feedback signals received from an identical communication station during the period of time; and a channel evaluation unit for estimating wireless channel quality of each communication station according to a geographical environment thereof based on the average values measured by the average measurement unit.

A communication system is disclosed in which a communication device communicates with communication apparatus that operates a cell within which the communication device is located. The cell is operated as a licensed assisted access (LAA) cell and has an associated physical uplink control channel (PUCCH). The communication device has a controller that is adapted to: generate a control signal for transmitting to said communication apparatus; perform a clear channel assessment (CCA) on said PUCCH before the control signal is transmitted; and block transmission of the control signal on said PUCCH when said CCA indicates that said channel is not clear. The communication device is further adapted, when said controller has not blocked said transmission of the control signal, to transmit the control signal to said communication apparatus in said PUCCH.

A method for transmitting and receiving a wireless signal in a wireless communication system and an apparatus therefor are disclosed. Specifically, a method for transmitting and receiving a wireless signal in an unlicensed band by a wireless communication device in a wireless communication system comprises the steps of: performing a clear channel assessment (CCA) during a predetermined time interval in the unlicensed band; and transmitting a wireless signal in the unlicensed band when it is determined that the unlicensed band is in an idle state where the unlicensed band is not occupied by other wireless communication devices, wherein when the wireless communication device uses a directional antenna, a first difference between a CCA range and an interference range when the wireless signal is transmitted and received using the directional antenna may be adjusted to be equal to a second difference between the CCA range and the interference range when the wireless signal is transmitted and received using an omni-directional antenna.

The invention discloses a carrier sense method and a system. According to the method, a transmitting terminal sends an idle channel to assess clear channel assessment (CCA) request frames on a main channel of a transmission channel which needs to be detected; the transmitting terminal sends request to send (RTS) frames on the transmission channel which needs to be detected after sending a point coordination function inter-frame space (PIFS) subsequent to transmission of the CCA request frame; and the transmitting terminal performs data transmission on the transmission channel transmitting clear to send (CTS) frames after receiving an indication that CTS frames are permitted to send. The invention also discloses the carrier sense system, which comprises a transmitting terminal and a receiving terminal. According to the method and the system, the power consumption of the receiving terminal is reduced and reliable CCA results of all transmission channels are provided.

A system and method of reducing interference in a wireless communication network is disclosed. The method comprises adapting a transmission power of a signal of a wireless communication device when a clear channel assessment threshold equals a predetermined limit and a packet error rate exceeds a predetermined packet error rate threshold. In particular, the method includes increasing the transmission power of the signal when the clear channel assessment threshold equals a lower limit and the packet error rate exceeds an upper packet error rate threshold and decreasing the transmission power of the signal when the clear channel assessment threshold equals an upper limit and the packet error rate falls below a lower packet error rate threshold.

A method and an apparatus for transmitting a resource, and a method for the HARQ retransmission using an unlicensed band include an operation of performing clear channel assessment (CCA) for the unlicensed band; and an operation of occupying a channel of the unlicensed band according to the CCA and determining whether or not the resource is transmitted based on a position of a transmission time interval (TTI) within a channel occupancy time (COT) for the channel.

A system, method, and signal are disclosed for line probing. The invention provides an improved signal for line probing having desirable characteristics. In various embodiments the signal comprises a periodic sequence having good autocorrelation characteristics. The periodic sequence of the invention provides a faster and more accurate evaluation of the channel. Another embodiment of the invention comprises processing of the received sequence to determine a desired or maximum data rate for the line or channel. The invention also provides an evaluation and calculation of the noise on the line or channel.

Techniques for and apparatus capable of implementing packet detection and signal recognition in wireless communications systems are disclosed. In particular, the disclosed techniques and apparatus incorporate at least one of relative energy detection operable on assessment of a relative energy threshold for an inbound signal borne across an RF channel, carrier sense operable upon on assessment of at least one of a peak-to-sidelobe ratio and peak-to-peak distance defined by the inbound signal, and comparison operable upon demodulated data corresponding to the inbound signal as compared to predetermined preamble data. Clear channel assessment is performed based on determinations undertaken by one or more of the aforementioned relative energy detection, carrier sense and comparison operations.

A method is provided for performing a clear channel assessment in a wireless network. The method involves first listening for channel energy on a wireless channel. Whatever channel energy is heard over the wireless channel is demodulated into non-synchronized in-phase and non-synchronized quadrature phase components. Each of the non-synchronized in-phase and non-synchronized quadrature phase components are squared, and then the non-synchronized in-phase component is multiplied by the non-synchronized quadrature phase component to produce an I−Q product. The sum of the squared non-synchronized in-phase component, the inverse of the squared non-synchronized quadrature component, and double the I−Q product is determined as a clear channel assessment input value. A carrier signal detection function is then performed on the clear channel assessment input value to produce a clear channel assessment output value, which is used to determine whether a signal is present in the wireless channel.

Uplink control channel management is disclosed for LTE/LTE-A communication systems with unlicensed spectrum in which two or more physical resource blocks (PRBs) are allocated for uplink control channel transmission. The uplink control information (UCI) payload may be determined based on clear channel assessment (CCA) information associated with carriers scheduled for transmission of the UCI data. With the UCI payload determined, two or more uplink control channel messages may be generated according to at least one control channel format, wherein uplink control channel messages include the UCI payload. These generated uplink control channel messages may then be transmitted over the allocated PRBs.