Abstract: A signal activity detector (SAD) combines at least three decision signals to generate a combined decision signal as input to a hangover addition circuit of the SAD. Each of the decision signals indicating whether or not activity is detected in the input signal according to respective decision criteria. The SAD sends the combined decision signal to the hangover addition circuit to generate a final decision signal of the SAD as to whether or not activity is detected in the input signal.

Abstract: An apparatus and method for an audio user interface solution that avoids the time variation problems seen when using an acoustic echo canceler in an audio system. The solution as disclosed and claimed herein results in lower CPU usage in the audio system because a synchronous sample rate correction (SSRC) is performed on the sample rate multiple rate content and the asynchronous sample rate correction (ASRC) is applied on a small number of signals used to feed the ASRC.

Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive a discovery reference signal from a base station on an anchor channel. The UE may perform a first random or pseudorandom frequency hopping procedure to identify a plurality of downlink carriers for a first time period. The UE may perform a second random or pseudorandom frequency hopping procedure within the plurality of downlink carriers to select one of the plurality of downlink carriers as the uplink channel for a second time period. The UE may then transmit an uplink communication during the second time period on the selected uplink channel. In some examples, the uplink communication may be transmitted based at least in part on time division multiplexing (TDM) information.

Abstract: An apparatus for selective AEC filter bypass is disclosed. A method and computer program product also perform the functions of the apparatus. An apparatus for selective AEC filter bypass is disclosed that includes a filter for an audio handling device that performs acoustic echo cancellation (AEC) on a microphone signal to produce an AEC-filtered microphone signal, a bypass controller that determines whether an AEC bypass parameter corresponding to an audio stream is enabled and a mixer that combines the audio stream with the AEC-filtered microphone signal to produce an AEC-filtered selectively combined signal in response to determining that the AEC bypass parameter corresponding to the audio stream is enabled.

Abstract: A method for performing uplink transmission in a time domain transmission unit includes receiving, from a base station, hopping-mode information indicating whether a frequency hopping is an inter-slot hopping or an inter-subframe hopping and performing the uplink transmission using a resource block in the time domain transmission unit.

Abstract: A first device of a Multimedia Over Coax Alliance (MoCA) network may communicate with a second device of the MoCA network to control power-save operation of the second MoCA device. The first device may control the power-save operation of the second MoCA device based on an amount of data stored in a buffer, wherein the data stored in the buffer is destined for the second device. The buffer may be in a third device which sends the data to the second device, and/or the buffer may be in the first device. The first device may be operable to buffer data destined for the second device while the second device is in a power-saving state.

Abstract: A method and apparatus for handling a control channel for carrier aggregation in wireless communications. The method includes determining which component carrier to listen to, detecting the downlink control channel, processing mapping information related to downlink and uplink transmissions and operating discontinuous reception with respect to carrier aggregation. The method also includes detecting a component carrier, determining the component carrier type and locating the anchor component carrier, if necessary, where the anchor component carrier carries the carrier aggregation information.

Abstract: An embodiment may include determining at least one respective amount of buffer memory to be used to store at least one respective portion of network traffic. The determining may be based at least in part upon at least one respective parameter associated with the at least one respective network traffic portion. The at least one respective amount may be sufficient to store the at least one respective portion of the network traffic. The at least one respective parameter may reflect at least one actual characteristic of the at least one respective portion of the network traffic. This embodiment also may permit at least one respective portion of the buffer memory that may correspond to the at least one respective amount to be selectively powered-on to permit the at least one portion of the buffer memory to be used to store the at least one respective network traffic portion.

Abstract: Apparatuses and methods are disclosed for automatic volume control of an audio stream reproduced by a captioning communication service for use by a call assistant in generating a text transcription of a communication session between a hearing-impaired user and a far-end user. The automatic volume control automatically adjusts a volume of the audio stream reproduced by the captioning communication service responsive to a volume control command identifying which of the far-end voice signal and the near-end voice signal is active at a given time. The system further includes an echo modifier configured to add distortion to an echo portion of the far-end voice signal when generating the audio stream.

Abstract: An echo component of a first signal received at an audio input device is removed. A second signal is output from an audio output device. The echo component in the first signal is the result of the second signal traversing an echo path. The characteristics of the first and second signals are compared, and if the first signal only comprises the echo, an estimate of the echo path is determined by comparing the first and second signals. The echo path estimate is applied to the first signal to determine an equalized first signal, which is is compared with the second signal to determine an estimate of the echo component. The echo component from the first signal is removed in dependence on the estimate of the echo component.

Abstract: An audio coding terminal and method is provided. The terminal includes a coding mode setting unit to set an operation mode, from plural operation modes, for input audio coding by a codec configured to code the input audio based on the set operation mode such that when the set operation mode is a high frame erasure rate (FER) mode the codec codes a current frame of the input audio according to a select frame erasure concealment (FEC) mode of one or more FEC modes. Upon the setting of the operation mode to be the High FER mode the one FEC mode is selected, from the one or more FEC modes predetermined for the High FER mode, to control the codec by incorporating of redundancy within a coding of the input audio or as separate redundancy information separate from the coded input audio according to the selected one FEC mode.

Abstract: Methods and apparatus permitting the coexistence of multiple communication links to distinct wireless systems in a client device are disclosed. A wireless device can interface with both a primary communications system and at least one distinct communications system by managing the coexistence of active communications with the multiple communication systems. The wireless device can initially configure communications with the primary communications system for dynamically reconfigurable time multiplexed operation having scheduled periods of inactivity. The wireless device can determine timing and scheduling of communications with the distinct communications systems and can schedule the communications with the distinct communications systems during periods of inactivity in the primary communications system. The periods of inactivity may be limited to the scheduled periods of inactivity or can include unscheduled periods of inactivity occurring during active periods of the time multiplexed operation.

Abstract: The invention relates to a method for communicating between at least one first system (2) and at least one second system (3) via a full-duplex synchronous serial link (4) capable of simultaneously routing data between said systems (2, 3), said data comprising: at least one message (12; 43) from the first system (2) to the second system (3), at least one message (16; 45) from the second system (3) to the first system (2), and a clock signal (13; 44). According to the method: the second system (3) receives a message (12; 43) and a clock signal (13; 44) sent by the first system (2), delayed and substantially in phase; the second system (3) sends the first system (2) a message (16; 45); the clock signal (13; 44) received by the second system (3) is returned (17; 46) to the first system (2) along with the message (16; 45) sent by the second system (3); and the first system (2) receives the message (16; 45) sent by the second system (3) and the returned clock signal (17; 46), delayed and substantially in phase.

Abstract: System and methods provide acoustic echo monitoring and cancellation for real time media processing in an internet protocol (IP) media server in an IP network. An echo monitor is configured to selectively compare audio streams into and out of the IP media server through a selected port. The comparison determines an occurrence of an echo. An echo canceller in communication with the echo monitor is configured to respond to the determination by the echo monitor so as to remove the echo from at least one of the audio streams. A talk burst detector may be used to detect speech in at least one of the audio streams through the selected port. The echo monitor selectively compares the audio streams in response to a signal from the talk burst detector that indicates detection of speech.

Abstract: Techniques for performing analysis of a cellular telephone signaling environment in the presence of interferers. The techniques do the analysis by employing a receiver to listen to the cellular environment during holes in the interference. The holes have a timing which differs from that used by the cellular telephone signaling environment and will thus over time overlap with structures of interest in the cellular telephone environment. The holes may be smaller than the structure of interest. The signals which the receiver hears in the holes are analyzed and combined to reproduce the structure. The combination may involve statistical methods and weighted decoding. The analysis obtains information which permits surgical attacks on individual wireless devices which are in the traffic state. Example applications of the techniques are given for the GSM and CDMA cellular telephone standards.

Abstract: Embodiments of the invention provide systems and methods for deactivating reactive jamming attacks and other sophisticated attacks in wireless sensor networks (WSNs). In one system, trigger nodes (nodes whose transmissions invoke jammer nodes) are identified and communications between the sensor nodes of the WSN are routed to avoid sending (e.g., transmitting) information from identified trigger nodes. For example, identified trigger nodes are routed as receivers only. One method of identification uses an advanced randomized error-tolerant non-adaptive group testing technique and a clique-independent set problem solution. Another method of identification uses a hexagon tiling coloring and sequential group testing scheme.

Abstract: An echo canceler 10 generates an echo elimination signal by filtering through adaptive filters 101 and 102 reference signals input from sound sources causing echoes. It includes a sound source number detecting unit 103 for detecting the number of the sound sources causing echoes from the reference signals, and a control unit 105 for making the number of taps of the adaptive filters 101 and 102 variable in accordance with the number of the sound sources detected by the sound source number detecting unit 103.

Abstract: A system and method for provide a stable gain from an adaptive gain control device in a signal path. An echo canceller is also located in the signal path, and is used to provide performance information regarding losses in the signal. This performance information is fed to the automatic gain control device via a connection. The automatic gain control device thereafter uses the performance information to determine a maximum gain that might be provided based upon losses cause by echo conditions. The gain however is limited in order to provide for a stable system. The performance information includes a loss rate that includes a combination of the echo return loss and the echo return loss enhancement.

Abstract: Aspects of a method and system for Ethernet Switching, Conversion, and PHY optimization based on link length in Audio/Video Systems are provided. In this regard, the length of a link over which a first communication device communicates with a second communication device may be determined and Ethernet PHY's residing in the communication devices may be configured based on the determination. One or both of the communication devices may comprise an Ethernet switch operable to switch packetized audio and/or video content. The packetized audio and/or video may be switched between the configured Ethernet PHY and one or more other Ethernet PHYs. Audio and/or video data may be received via the one or more corresponding Ethernet PHYs, the received audio and/or video data may be reformatted to be compatible with an audio and/or video interface, and the reformatted audio and/or video data may be transmitted via the audio and/or video interface.

Abstract: Speech frames of a first speech coding scheme are utilized as speech frames of a second speech coding scheme, where the speech coding schemes use similar core compression schemes for the speech frames, preferably bit stream compatible. An occurrence of a state mismatch in an energy parameter between the first speech coding scheme and the second speech coding scheme is identified, preferably either by determining an occurrence of a predetermined speech evolution, such as a speech type transition, e.g. an onset of speech following a period of speech inactivity, or by tentative decoding of the energy parameter in the two encoding schemes followed by a comparison. Subsequently, the energy parameter in at least one frame of the second speech coding scheme following the occurrence of the state mismatch is adjusted. The present invention also presents transcoders and communications systems providing such transcoding functionality.

Abstract: Systems, methods, and other embodiments associated with echo cancellation are described. According to one embodiment, a method uses two signals from a transmitter as input to a look-up table to generate a non-linear echo cancellation signal. The non-linear echo cancellation signal is applied to a receiving path to reduce non-linear echo distortion on the receiving path based at least in part on the current signal and the previous signal.

Abstract: A multimedia conferencing system includes a loud speaker system, one or more microphones for receiving a local audio signal and a remote audio signal, a state machine and an echo canceller that operates in conjunction with two reference signals to remove substantially all of a feedback signal component in the local audio signal that results from reinforcing and playing the local audio signal over the loud speaker system. The state machine operates to detect that only the local audio is active, and if so controls the operation of the echo canceller such that only the feedback component of the local audio signal is removed and the local audio signal is not suppressed.

Abstract: A method for performing a call between a near-end user and a far-end user, which includes the following operations performed during the call by the near-end user's communications device. Automatic gain control (AGC) is performed to update a gain applied to an uplink speech signal. A frame is detected in a downlink signal that contains speech; in response, the updating of the gain is frozen. Other embodiments are also described and claimed.

Abstract: A voice communication end device provides echo reduction when operating in a full duplex mode using acoustic echo cancellation, which includes periodic audio queue adjustments to account for drift. The end device performs a quality assessment by calculating consistency statistics for the queue adjustments to determine whether acoustic echo cancellation would be ineffective, and if so falls back to a half duplex mode using voice switching.

Abstract: A cancellation system is disclosed for processing incoming and outgoing signals in a transform domain to create a cancellation signal for reducing or removing unwanted interference. Data is ordered based on Good-Thomas indexing into a two dimensional array in a buffer. The two dimensional array may have lr rows and lw columns. From the buffer, the columns of data undergo a Winograd small transform. The rows of data undergo a Cooley-Tukey operation to complete the transform operation into the frequency domain. Multipliers scale the transformed data to generate a cancellation signal in the frequency domain. Inverse (Cooley-Tukey) and Winograd transforms perform inverse processing on the cancellation signal to return the cancellation signal or data to the time domain. Re-ordering the data and combination of the cancellation signal or data with incoming or outgoing signals achieve interference cancellation.

Abstract: A system, method, and program product are provided for filtering sound from a selected application on a computer without interrupting voice communications on the computer. The method comprises: monitoring a selected program for an outgoing digital audio signal from a selected application; detecting said digital audio signal; and filtering an analog microphone input with the digital audio signal.

Abstract: Sound signals captured by a microphone are adjusted to provide improved sound quality. More particularly, an Acoustic Echo Reduction system which performs a first stage of echo reduction (e.g., acoustic echo cancellation) on a received signal is configured to perform a second stage of echo reduction (e.g., acoustic echo suppression) by segmenting the received signal into a plurality of frequency bins respectively comprised within a number of frames (e.g., 0.3 s to 0.5 s sound signal segments) for a given block. Data comprised within respective frequency bins is modeled according to a probability density function (e.g., Gaussian distribution). The probability of whether respective frequency bins comprise predominantly near-end signal or predominantly residual echo is calculated.

Abstract: In a data processing system, a method includes receiving samples of a send path input signal (Sin) and samples of a receive path input signal (Rin); in response to receiving each sample of the send path input signal, providing a double-talk indicator to indicate whether or not double-talk has been detected; using the double-talk indicator to determine a double-talk density within a predetermined number of samples of the send path input signal or the receive path input signal; and using the double-talk density to provide a heavy double-talk indicator which indicates whether or not heavy double-talk has been detected. In response to the heavy double-talk indicator indicating that heavy double-talk has been detected, a heavy double-talk mode may be entered.

Abstract: A network interface including: a medium access control device configured to operate at a first power state during an inactive power mode, and operate at a second power state during an active power mode; a physical layer device including (i) an energy detect module configured to detect energy on a medium during the inactive power mode, and (ii) an energy save module configured to time a first pre-determined period subsequent to the energy detect module detecting energy on the medium. The medium access control device is further configured to, subsequent to the energy detect module detecting energy on the medium, transition to the second power state of the active power mode, and communication with the medium access control device via the medium is enabled subsequent to expiration of the first pre-determined period.

Abstract: Methods and apparatus are provided for CDR and equalization update qualification. A block of received data comprising a plurality of multiple tone patterns is processed. Equalization adaptation and/or updates to a timing recovery process can be selectively disabled if one or more of the multiple tone patterns exceed a corresponding predefined threshold.

Abstract: The method for an eNodeB transmitting control channels with pre-allocated resources comprising steps of the eNodeB determining whether to transmit the control channels according to its needs; the eNodeB transmitting the control channels with pre-allocated resources according to properties of the signaling to be transmitted. With the method proposed in present invention, operations in a receiving end are simplified so that the time spent in receiving signaling is shortened and power consumption is well reduced.

Abstract: A startup protocol is provided for use in a communications system having a communications line with a master transceiver at a first end and a slave transceiver at a second end, each transceiver having a noise reduction system, a timing recovery system and at least one equalizer all converging at startup of the system. The operation of the startup protocol is partitioned into stages. The first stage includes the step of converging the equalizer and the timing recovery system of the slave while converging the noise reduction system of the master. Upon completion of the first stage the protocol enters a second stage which includes the step of converging the equalizer and the timing recovery system of the master, converging the noise reduction system of the slave, freezing the timing recovery system of the slave, and resetting the noise reduction system of the master.

Abstract: A startup protocol is provided for use in a communications system having a plurality of transceivers, one transceiver acting as a master and another transceiver acting as slave, each transceiver having a noise reduction system, a timing recovery system and at least one equalizer. The operation of the startup protocol is partitioned into three stages. During the first stage the timing recovery system and the equalizer of the slave are trained and the noise reduction system of the master is trained. During the second stage the timing recovery system of the master is trained in both frequency and phase, the equalizer of the master is trained and the noise reduction system of the slave is trained. During the third stage the noise reduction system of the master is retrained, the timing recovery system of the master is retrained in phase and the timing recovery system of the slave is retrained in both frequency and phase.

Abstract: A communication system includes transmit and receive paths, a balancing filter, a noise generator, a detector, and an interface. The transmit path is operable to generate data for communication on a communication network. The receive path is operable to receive data from the communication network. The balancing filter is coupled between the transmit path and the receive path. The noise generator is operable to inject a noise signal on the receive path. The detector is operable to measure reflected power in the transmit path associated with the noise signal. The interface is operable to receive a plurality of sets of coefficients for configuring the balancing filter, wherein the detector is operable to measure the reflected power for each of the sets of coefficients.

Abstract: A method and apparatus for removing an echo signal in a signal transmission/reception apparatus of a communication system is provided. A signal transmission/reception apparatus estimates an input channel response using a training sequence, generates a first signal by removing the input channel response from a first reception signal, detects an echo channel impulse response using the first signal, detects an echo signal removing coefficient using the echo channel impulse response, generates a second signal in which an echo signal is removed by applying the echo signal removing coefficient to a second reception signal, and removes the second signal from a third signal, wherein the first signal is received prior to receiving the second signal and the second signal is received prior to receiving the third signal.

Abstract: Signal detectors are described herein. By way of example, a system for detecting signals can include a microphone signal detector, a loudspeaker signal detector, a signal discriminator and a decision component. When the microphone signal detector detects the presence of a microphone signal, the loudspeaker signal detector detects the presence of a loudspeaker signal and the signal discriminator determines that near-end speech dominates loudspeaker echo, the decision component can confirm the presence of doubletalk. When the microphone signal detector detects the presence of a microphone signal and the signal discriminator determines that near-end speech dominates loudspeaker echo, the decision component confirms the presence of near-end signal.

Abstract: An apparatus having a corresponding method and computer program comprises an input circuit to receive packets of data from a network; a memory to store packet filter criteria for one or more wireless clients; a filter circuit to drop one or more of the packets of data according to the packet filter criteria; and a wireless output circuit to wirelessly transmit, to the one or more wireless clients, only the packets of data that are not dropped by the filter circuit.

Abstract: A device reconfigurable to support communication using different communication technologies is provided. The device includes, but is not limited to, a plurality of communication processing modules and a switching interface. The switching interface couples to the plurality of communication processing modules. An instruction set is written into the device to select one or more communication processing module of the plurality of communication processing modules to connect using the switching interface. One or more of the communication processing modules may be programmable. The instruction set may include programmable parameters and/or programming instructions for the one or more programmable communication processing modules. As a result, the device is reprogrammable and reconfigurable to process different communication signals while utilizing less power than conventional designs.

Abstract: A system for suppressing transmission channel noise in a signal transmission/reception device—particularly a time division duplex (TDD) wireless communications device—is provided. The system provides one or more shunt elements, instantiated at some point along the device's signal transmission channel. One or more attenuation elements are also instantiated at some point along the signal transmission channel, as are one or more disabling elements. A trigger signal indicates when the device is shifting from signal transmission operation (or mode) to signal reception operation. Responsive to assertion of the trigger signal, the shunt, attenuation and disabling elements are activated.

Abstract: This invention provides a technique to reduce echoes not adequately attenuated by echo cancellers during initial periods of voice communication. Signals transmitted across communication networks are often reflected back to the caller resulting in echo. Echo cancellers are employed in the communication system to cancel this effect in order to maintain a high quality transmission. However, echo cancellers require time to detect, adapt, and effectively remove echo, often resulting in echo during the initial moments of the call and thereby degrading the quality of service. By installing an attenuation device into the communication system, all signals that pass through it are reduced to a preset value for a set period of time. This reduces any echo below a detectable threshold. After the period of time expires, the attenuation device allows the signal to pass unaffected, by which time the echo cancellers have adaptively adjusted to any echoes in the system.

Abstract: A demodulator cancels out the echo signal properties in the received signal to generate a primary signal, and cancels out the primary signal properties in the received signal to generate a separate echo signal. In addition, the demodulator may combine the primary signal and the echo signal in a comparison/combination operation to generate a third combined signal. Error correction operations may then be performed on all three of the primary signal, echo signal and combined signal, with the results of those error correction operations being used to select which of the three signals will serve as the transport stream.

Abstract: A network communication apparatus that includes a function for performing communications via an IP network and that includes an ITU-T standard T.38 communication function but does not include a voice communication function is disclosed. The network communication apparatus includes: a unit configured to generate a call connection signal including T.38 communication capability and dummy voice capability to start call connection operation; and a unit configured to perform T.38 communication operation after sending a dummy CNG packet when detecting that a second network communication apparatus at the other end does not include the T.38 communication function based on a call connection signal received from the second network communication apparatus.

Abstract: A Time Division Duplex (TDD) wireless communication system includes a switch connected to an output port of a transmitter, a first transmission line for transmitting a transmission signal and for isolating a transmission path according to a mode, a first transmission line stub connected between the isolator and the first transmission line for reflecting a transmission signal transmitted from the isolator, a second transmission line connected between an output port of the first transmission line and an input port of a receiver for isolating a reception path in the transmission mode and for providing a reception signal received from the antenna feed line to the receiver, and a second transmission line stub connected in a stub form between the second transmission line and the input port of the receiver, for controlling the second transmission line to isolate the reception path.

Abstract: Automatic Protection Switching (APS) and error signal processing coordination apparatus and methods are disclosed. If a communication module that enables communication signals and error signals to be exchanged with a remote communication module is configured in an APS protection group, error signal processing by the communication module is restricted. This prevents Time Division Multiplexing (TDM) T1/E1 Remote Defect Indication (RDI) signal processing, for example, from interfering with Synchronous Optical Network/Synchronous Digital Hierarchy (SONET/SDH) unidirectional One-plus-One APS. Under certain conditions, however, a restricted communication module may be allowed to perform a restricted error processing operation or revert to normal unrestricted error signal processing.

Abstract: A voice communication end device performs quality checks to determine whether acoustic echo cancellation would be ineffective, such as due to noise or clock drift or discontinuities between incoming and outgoing voice channels. In the case where echo cancellation would prove ineffective, the device falls back on a tri-state voice switching operation that includes a bi-direction state in which both channels are on in full duplex operation, which provides a smoother transition switching between active channels. The tri-state voice switching supports both voluntary transitions where the active user voluntarily stops to yield the active channel, and forced transitions where the active user is forcedly interrupted by the other user speaking more loudly.

Abstract: A method of shaping an orthogonal frequency division multiplexing (OFDM) signal spectrum of a transmitted signal is disclosed. An input signal including an input component is received and a first instance of the input component is generated. The method also includes determining that a second instance of the input component is to be different than the first instance. The second instance of the input component that is different from the first instance is generated. An output signal to be transmitted is generated and includes the first instance and the second instance of the input component.

Abstract: A startup protocol is provided for use in a communications system having a communications line with a master transceiver at a first end and a slave transceiver at a second end, each transceiver having a noise reduction system, a timing recovery system and at least one equalizer all converging at startup of the system. The operation of the startup protocol is partitioned into stages. The first stage includes the step of converging the equalizer and the timing recovery system of the slave while converging the noise reduction system of the master. Upon completion of the first stage the protocol enters a second stage which includes the step of converging the equalizer and the timing recovery system of the master, converging the noise reduction system of the slave, freezing the timing recovery system of the slave, and resetting the noise reduction system of the master.

Abstract: Method for upgrading software in a network bridge that is part of a VLAN includes sending notification to other bridges of the VLAN that the bridge is scheduled for upgrading; suspending VLAN registration and membership information in the other bridges while upgrading the bridge; restoring a state of the updated bridge and sending notification to the other bridges that the upgrading has been completed. As a result of the notification, the other bridges do not expect additional messages from the upgrading bridge. The step of restoring a state of the bridge includes synchronizing a GVRP protocol running within the network to a current VLAN membership table. Apparatus includes a forwarding plane adapted to store VLAN membership information and a control plane adapted for issuing and executing instructions that control registration and de-registration of one or more ports of the bridge according to the VLAN membership information and the presented method.

Abstract: A startup protocol is provided for use in a communications system having a plurality of transceivers, one transceiver acting as a master and another transceiver acting as slave, each transceiver having a noise reduction system, a timing recovery system and at least one equalizer. The operation of the startup protocol is partitioned into three stages. During the first stage the timing recovery system and the equalizer of the slave are trained and the noise reduction system of the master is trained. During the second stage the timing recovery system of the master is trained in both frequency and phase, the equalizer of the master is trained and the noise reduction system of the slave is trained. During the third stage the noise reduction system of the master is retrained, the timing recovery system of the master is retrained in phase and the timing recovery system of the slave is retrained in both frequency and phase.

Abstract: The invention relates to communication between terminals. Where communication is over an ideal channel then a high throughput modulation scheme can be used. Where the terminals suffer interference or noise, transmission can be modified to a more robust modulation scheme. The modulation scheme for a signal to be transmitted from the terminal is normally selected based up measurements made on a signal received by the terminal. However, the uplink and downlink between two terminals may not be experiencing the same interference and noise. For example, an interfering source may affect one terminal more than another. Under these circumstances, the terminal will not get a good picture of the status of the channel or link over which it is about to transmit. Therefore, the invention provides a system where quality information is passed from the terminal receiving a signal to the terminal which sent the signal to help to determine the most appropriate modulation scheme.