摘要:
A system and method enable a wireless device to support simultaneously multiple push-to-talk (PTT) communications and interrupt certain PTT communication with higher priority ones. A user (302) subscribes to multiple PTT communication groups (314, 316) and designates one of the groups as the primary group. The wireless device receives and plays PTT communications from the multiple PTT communication groups and interrupts playing of a PTT communication from a non-primary group if a PTT communication is received from the primary PTT communication group.
摘要:
A wireless terminal receives base station position over an airlink, determines its relative position with respect to the base station and determines a timing adjustment correction. The wireless terminal applies the determined timing correction to control uplink signaling timing and achieve synchronization at the base station's receiver. The wireless terminal determines its relative velocity with respect to the base station and determines a Doppler shift adjustment which it adds to the uplink carrier frequency or to its baseband signal. A wireless terminal determines the position of a moving base station and determines timing and/or frequency corrections. Base station position is determined from the current time and stored information correlating the base station position with time, e.g., for a geo-synchronous satellite. Base station position information is determined from broadcast information, e.g., GPS base station position, for an aircraft base station. Wireless terminals may be mobile and include a GPS receiver for WIRELESS TERMINAL position determination.
摘要:
Downlink traffic channel data rate options and methods of indicating to a wireless terminal a utilized downlink data rate option are described. The downlink traffic channel rate option for a segment is conveyed using an assignment signal and/or a block in the downlink traffic channel segment which is not used for user data. Downlink segment assignment signals in some implementations allocate fewer bits for rate option indication than are required to uniquely identify each option, hi some implementations low rate options, e.g., using QPSK, are uniquely identified via assignment signals. Higher rate options, e.g., using QAMl 6 modulation, are conveyed via the distinct information block in the downlink traffic segment using a first coding/modulation method. Still higher rate options, e.g., using QAMl 6, QAM64, or QAM256, are conveyed via the information block in the segment using a second coding/modulation method which is applied to the rate option information.
摘要:
A wireless terminal using OFDM signaling supporting both terrestrial and satellite base station connectivity operates using conventional access probe signaling in a first mode of operation to establish a timing synchronized wireless link with a terrestrial base station. In a second mode of operation, used to establish a timing synchronized wireless link with a satellite base station, a slightly modified access protocol is employed. The round trip signaling time and timing ambiguity between a wireless terminal and a satellite base station is substantially greater than with a terrestrial base station. The modified access protocol uses coding of access probe signals to uniquely identify a superslot index within a beaconslot. The modified protocol uses multiple access probes with different timing offsets to further resolve timing ambiguity and allows the satellite base station access monitoring interval to remain small in duration. Terrestrial base station location/connection information is used to estimate initial timing.
摘要:
A stream of modulation symbols from a zero symbol rate (ZSR) coding/modulation module and a stream of modulation symbols from another type of coding/modulation module are input into an interweaver module. The interweaver module mixes the two input streams when assigning modulation symbols to be communicated in a segment. If a ZSR modulation symbol is non-zero, the ZSR modulation symbol is allocated a transmission position. If the ZSR modulation symbol is a zero modulation symbol, the modulation symbol from the other coding/modulation module is allocated the transmission position. The non-zero modulation symbols from the ZSR module are higher in power than the non-zero modulation symbols from the other module, thus facilitating detection and recovery.
摘要:
Group communications methods and apparatus are described. Multicast operation is supported with the transmission characteristics (1003, 1052), e.g., transmission power level, coding rate, and/or modulation method being selected to reliably communicate information to the end nodes (134, 136, 144, 146, 154, 156) in the group but not necessarily to all end nodes within the cell or sector (138, 148, 158). Thus resources can be conserved by matching transmission requirements with information on the requirements of one or more group members. The requirements for reliably reaching the end node with the worst channel conditions can, and in some embodiments is, used to determine the group transmission requirements. Power level and other transmission resource allocations can change in response to changes in group membership and/or conditions corresponding to existing group members.
摘要:
A flexible and relatively hardware efficient LDPC decoder (900) is described. The decoder cai be implemented with a level of parallelism which is less than the full parallelism of the code structure used to control the decoding process (901). Each command of a relatively simple control code used to describe the code structure can be stored and executed multiple times to complete the decoding of a codeword. Different codeword lengths (912) are supported using the same set of control code instructions but with the code being implemented a different number of times depending on the codeword length. The decoder can switch between decoding codewords of different lengths, without the need to change the stored code description information, by simply changing a code lifting factor (908) that is indicative of codeword length and is used to control the decoding process. When decoding codewords shorter than the maximum supported codeword length some block storage locations may go unused (916).
摘要:
MIP forwarding methods are described that use additional access link-layer identifiers and redirecting data packet identifiers to provide unambiguous forwarding through the MIP Foreign Agent when the Mobile Node has multiple Home Addresses, and/or when the Home Agent, or some intermediate MIP node between the Foreign Agent and the Home Agent, supports multiple pools of home addresses from overlapping address spaces. New identifiers are used to ensure that sufficient forwarding information exists in conjunction with the information in transmitted packets, to uniquely identify each packet flow. Each packet flow is a globally unique quartet of the MN identity, the HA, the HA address pool and the HoA.
摘要:
Methods and apparatus for efficient two-stage paging wireless communications systems are described. Wireless terminals are assigned to paging groups. A few first paging message information bits are modulated (using non-coherent modulation) into a first paging signal and communicated from a base station to wireless terminals. WTs wake-up, receive the first paging signal and quickly ascertain whether its paging group should expect a second paging signal, if so, the WT is operated to receive the second paging signal; otherwise, the WT goes back to sleep conserving power. The base station modulates (using coherent modulation) a number of second message information bits into a second paging signal and transmits the signal to WTs. From the information in first and second paging signals, a WT can determine that it is the paged WT and process the paging instructions. The intended paged WT can transmit an acknowledgement signal on a dedicated uplink resource.
摘要:
Transmit and/or receive diversity is achieved using multiple antennas. In some embodiments, a single transmitter chain within a wireless terminal is coupled over time to a plurality of transmit antennas (312). At any given time, a controllable switching module (310) couples the single transmitter chain to one the plurality of transmit antennas. Over time, the switching module couples the output signals from the single transmitter chain to different transmit antennas. Switching decisions are based upon predetermined information, dwell information, and/or channel condition feedback information. Switching is performed on some dwell and/or channel estimation boundaries. In some OFDM embodiments, each of multiple transmitter chains is coupled respectively to a different transmit antenna. Information to be transmitted is mapped to a plurality of tones. Different subsets of tones are formed for and transmitted through different transmit chain/antenna sets simultaneously. The balance of tones allocated to the subsets for each antenna are changed as a function of predetermined information, dwell information, and/or channel condition feedback information.