Abstract: In the present invention, the subscriber unit (200) obtains a set of access point identifiers and measurement opportunity information for each access point identifier. A first measurement is performed on a first access point identified from the set of access point identifiers. A current timer value is determined after completing the step of performing, and a second access point identified from the set of access point identifiers in which to perform a second measurement is selected. Selecting the second access point is based on at least the measurement opportunity information for the second access point in relation to the current timer value.

Abstract: The invention concerns a method (200) and system (100) for improving the efficiency of a mobile station (112) during a listening interval (310). The method can include the step of setting (212) a paging message indicator (414) or a neighbor advertisement message indicator (416) in which the paging message indicator indicates whether a paging message (314) is the last paging message designated for the mobile station in the listening interval and the neighbor advertisement message indicator indicates the presence of a neighbor advertisement message (316). The method can also include the step of transmitting (214) the paging message indicator or the neighbor advertisement message indicator to the mobile station. Based on these indicators, the mobile station can selectively enter a sleep state during and/or after the listening interval to conserve battery life.

Abstract: The invention concerns a method (200) and system for improving transmission or receipt of channel descriptors. The method can include the steps of—in a wireless communication system (100) that periodically broadcasts regular channel descriptors (310) at a set interval (312)—changing (212) a modulation scheme and transmitting (216) one or more supplementary channel descriptors (314) during the set interval between regular channel descriptors. The method can also include the step of periodically transmitting (214) a channel descriptor count (412) that provides an indication of the changed modulation scheme.

Abstract: In the present invention, the subscriber unit (200) obtains a set of access point identifiers and measurement opportunity information for each access point identifier. A first measurement is performed on a first access point identified from the set of access point identifiers. A current timer value is determined after completing the step of performing, and a second access point identified from the set of access point identifiers in which to perform a second measurement is selected. Selecting the second access point is based on at least the measurement opportunity information for the second access point in relation to the current timer value.

Abstract: A mobile station (204) in a wireless local area network is associated with an access point (202), which controls timing of certain transmissions, such as beacons (402). The mobile station has a timer (108) that is driven by a high frequency clock source (110) while operating in an active mode, and a low frequency clock source (112) when in a low power mode, to conserve battery charge. To prevent timing errors from significantly affecting the accuracy for the timer (108) upon transitioning from one mode to the other, access point transmits timing information to the mobile station in the course of servicing requests from the mobile station. The timing information is included in a response sequence (300).

Abstract: A wireless local area network (WLAN) includes an access point (102) and a mobile station (106). The mobile station can operate in a low power mode by shutting down a WLAN subsystem (204) of the mobile station. While the mobile station is in a low power mode, the access point buffers data received at the access point destined for the mobile station (706). The mobile station wakes up to initiate a service period by transmitting a trigger frame to the access point, and identifies a traffic stream to be serviced in the presently initiated service period. The access point begins transmitting response frames to the mobile station, identifying the traffic stream requested by the mobile station, and in at least one response frame, the access point may indicate the buffer status of another traffic stream associated with the mobile station to allow the mobile station to make decisions regarding data retrieval and power save state.

Abstract: A mobile terminal (302, 304) wakes up from a low power state and initiates a frame exchange in a wireless local area network that supports voice traffic by transmitting a polling frame (602). If the mobile terminal had voice data to send, it is included in the polling frame. In response to receiving the polling frame, the access point transmits a delay frame (604) to acknowledge receipt of the polling frame. If the access point has data for the polling mobile terminal, it transmits a non-delay frame (606) including the voice data, otherwise it transmits a null frame (702). The mobile terminal acknowledges the data from the access point (608), and goes back to sleep until the beginning of the next service interval.

Abstract: A mobile station (106) establishes a real time communication link via an access point (102) for carrying voice or other time-sensitive data. A WLAN subsystem (204) of the mobile station is normally kept in a low power state. Upon initiating a communication link the mobile station signals to the access point that uplink poll-based power save delivery mode will be used (614), and the access point reserves resources to assure the necessary quality of service. The mobile station initiates a frame transaction by first powering up the WLAN subsystem (712), acquiring the WLAN channel (407), and transmitting a polling frame. Upon successful receipt of the polling frame the access point prepares to reply with a response frame at an unspecified time within service window, during which time the mobile station maintains the WLAN subsystem power up and ready to receive the response frame. Upon successful receipt of the response frame, the mobile station places the WLAN subsystem back into a low power state.

Abstract: A mobile station establishes a schedule by which data is exchanged with an access point. The schedule allows the mobile station to use a low power mode at times outside of the scheduled service periods. However, the mobile station may occasionally need to retrieve additional data from the access point, or transmit additional data to the access point, and so initiates an unscheduled service period to do so.

Abstract: A mobile station (106) establishes a real time communication link via an access point (102) for carrying voice or other time-sensitive data. A WLAN subsystem (204) of the mobile station is normally kept in a low power state. Upon initiating a communication link the mobile station signals to the access point that unscheduled power save delivery mode will be used (614), and the access point reserves resources to assure the necessary quality of service. The mobile station initiates a frame transaction by first powering up the WLAN subsystem (712), acquiring the WLAN channel (407), and transmitting a polling frame. Upon successful receipt of the polling frame the access point prepares to reply with an aggregate response. The aggregate response commences by transmitting all data in an aggregate buffer, including both reserved and unreserved data buffers. Upon successful receipt of the aggregate response, the mobile station places the WLAN subsystem back into a low power state.

Abstract: The invention provides an enhanced passive scanning method for a wireless local area network, including the steps of transmitting at least one of a beacon signal or a gratuitous probe response in a WLAN channel by an access point. The gratuitous probe response is a supplemental beacon signal that is transmitted at intervals between the occurrence of regular beacon signals, but contains only essential information to allow mobile station manage roaming and timing.

Abstract: A communication unit (10) can have at least a first receiver (11) and a second receiver (12). The latter typically consumes more power than the former during ordinary operation. Pursuant to one embodiment a communication unit can use the lower-power receiver to detect energy on a monitored channel while the second receiver is retained in a reduced power mode of operation. Upon detecting an absence of channel activity the second receiver can be restored to normal operability to effect such activities as are then presently required.

Abstract: An access point utilizes information (11) as provided by various subscriber units to provide a message (12) (as included with, for example, a beacon transmission) that reflects near term likely utilization of a shared communication resource. A subscriber unit (20) can then utilize that information to schedule its own monitoring activity. This, in turn, permits the subscriber unit to similarly schedule power saving activities to accommodate this reception schedule.

Abstract: The invention provides an enhanced passive scanning method for a wireless local area network, including the steps of receiving (405) at least one of a beacon signal (342, 348) or a gratuitous probe response (344), updating (435) a site timing table entry in a site timing table based on the received beacon signal (342, 348) or gratuitous probe response (344), setting (445) a scan start time based on entries in the updated site timing table, and determining (450) a power mode for a wireless communication device based on the scan start time. An enhanced passive scanning system (200, 500, 600) and computer usable medium for enhanced passive scanning is also disclosed.

Abstract: A method of providing RF signal quality information which includes the step of a probe request generator (110) monitoring a channel for probe requests being transmitted by a station (115) and/or probe responses being transmitted by an access point (105). The probe request generator can determine a time period between the successive probe request transmissions received from the station or successive probe responses received from the AP. The probe request generator can generate a series of probe requests (150) having the determined time period between successive probe request transmissions. The series of probe requests signal an access point (105) to transmit probe responses (155) which are detectable by the station.

Abstract: A system controller (106) is for transferring a low bit rate digital voice message. The system controller generates from an analog voice signal representing the voice message a set of speech model parameters, and generates a first derived set of speech model parameters from a first subset of the set of speech model parameters, the first derived set encoding the voice signal at a second voice quality and second vocoder rate that are less, respectively, than a first voice quality and vocoder rate. The system controller transmits (3610) the low bit rate-digital voice message comprising the first derived set of speech model parameters to a communication receiver (114). The communication receiver requests (3640) an incremental message when the quality of the voice message is unsatisfactory. The system controller generates and transmits (3555, 3650) an incremental message-and the communication receiver uses (3660) the incremental message to generate a higher quality voice message.

Abstract: A system controller (106) includes a speech encoder (107) that encodes a low bit rate digital voice message. The speech encoder sets values of words of a header of the encoded message. The values of the words define a quantity of frames in the voice message, N, and define a vocoder rate used for the encoded message. The speech encoder sets a state of each indicator in each frame status field of N frame status fields that are transmitted after the header of the encoded message. The speech encoder assembles N frame data fields, wherein each of the frame data fields comprises a set of data words. The N frame data fields follow the N frame status fields. Each set of data words conforms to at least one of the vocoder rate and the states of the indicators. A decoder (3310) decodes the encoded low bit rate digital message.

Abstract: A pitch determiner (931) of a system controller (106) that generates a smoothed pitch value for a current frame of a low bit rate voice message includes a pitch function generator (955) that generates a pitch detection function (PDF) for each frame of digital samples of a voice signal, a pitch candidate selector (960) that selects a future frame pitch candidate from a pitch detection function (PDF), and a pitch adjuster (978) that generates the smoothed pitch value. The pitch adjuster includes a subharmonic pitch corrector (965) that determines a future frame pitch value by performing pitch subharmonic correction of a future frame pitch candidate using a roughness factor of the frequency transformed window.

Abstract: A system controller (106) includes a speech encoder (107) that dynamically segments frames of a low bit rate digital voice message. Speech model parameters have been generated in a sequence of frames. The speech model parameters include quantized speech spectral parameter vectors. The speech encoder selects (1820) a first quantized speech spectral parameter vector as a current anchor vector, selects (1820, 1830) a second quantized speech spectral parameter vector located a predetermined number of frames (LMAX) from the current anchor vector as a target speech parameter vector, and perturbs (1840) the target speech parameter vector to derive a plurality (K) of perturbed speech parameter vectors.

Abstract: A technique is used in a speech encoder (107) that reduces non-speech activity of a low bit rate digital voice message. Speech model parameters that include quantized speech spectral parameter vectors are generated in a sequence of frames. A determination is made as to which frames of the sequence of frames are voiced frames and which frames are unvoiced frames. A consecutive sequence of frames of unvoiced frames is identified (2330) as an unvoiced burst when a length, NUV, of the consecutive sequence of frames exceeds a predetermined length, Ns. A non-speech activity portion of the unvoiced burst is identified (2335-2365) and removed.