Systems for communicating data through a satellite are disclosed. The systems generally include a radio designed for terrestrial communications that is configured to uplink data to one or more satellites. The one or more satellites are configured to receive the data from the terrestrial radio. In addition, the systems include terrestrial receivers, such as one or more chirp spread spectrum radios, positioned at ground level, which are configured to receive the data from the one or more satellites.

A mobile communication method according to the present invention includes the steps of: sending “INVITE” from a UE#1 to a P-CSCF/VATF in a visited network of the UE#1; sending “INVITE” from the P-CSCF/VATF to an IMS; and allocating, by the P-CSCF/VATF, an MGW#1 to the path for voice communications.

Methods and systems for calibrating the return and forward links of a satellite communication system are provided according to embodiments of the invention. The phase and/or amplitude variations caused by the return and forward links are calculated and/or estimated to aid in beamforming, such as ground-based beamforming. Calibration earth stations, distributed within one or more beam patterns, may be used to transmit calibration codes to the gateway to calibrate the return link. Return links variations may be estimated using a weighted minimum mean square algorithm at the gateway. Forward links may be calibrated with calibration codes transmitted from the gateway through a hybrid matrix to at least one calibration station. Forward calibration links may also calibrate for temperature-dependent signal variations such as diplexer variations at the satellite.

Aspects related to allocating transmission power in wireless communications are described. It can be determined whether data is to be transmitted on an uplink control channel in one or more upcoming transmission time intervals (TTIs). Based on this determination, transmission power is allocated to an uplink enhanced dedicated channel in the one or more upcoming TTIs. Where uplink control channel data is not to be transmitted in the one or more upcoming TTIs, transmission power that would have been used for the uplink control channels can instead be allocated to the enhanced dedicated channel.

A method for compensating group delay variations in a CDMA spread spectrum receiver, comprising: receiving an RF signal; generating an ideal replica signal; filtering the RF signal by one or more filters; obtaining an ideal auto-correlation function (ACF) of the ideal replica signal; distorting the ideal ACF to generate a distorted ACF by a filtering model of the one or more filters; aligning the ideal ACF and the distorted ACF; calculating a set of correction factors based on a ratio of the ideal ACF and the distorted ACF; calculating a cross-correlation signal based on the filtered RF signal and the ideal replica signal; and obtaining a compensated correlation signal by applying the set of correction factors to the cross-correlation signal.

A method for compensating group delay variations in a CDMA spread spectrum receiver, comprising: receiving an RF signal; generating an ideal replica signal; filtering the RF signal by one or more filters; obtaining an ideal auto-correlation function (ACF) of the ideal replica signal; distorting the ideal ACF to generate a distorted ACF by a filtering model of the one or more filters; aligning the ideal ACF and the distorted ACF; calculating a set of correction factors based on a ratio of the ideal ACF and the distorted ACF; calculating a cross-correlation signal based on the filtered RF signal and the ideal replica signal; and obtaining a compensated correlation signal by applying the set of correction factors to the cross-correlation signal.

An efficient return channel spectrum utilization technique for communication systems supporting adaptive spread spectrum. Requests for bandwidth allocation using a spread factor are analyzed to determine if there are any channels capable of supporting the spread factor. The request is acknowledged if at least one channel is capable of supporting the request. Adjacent channels required to accommodate the requested spread factor are reserved, and additional bandwidth requests are allocated on non-reserved channels.

Provided are a method and a device for performing communication using a non-orthogonal code multiple access scheme in a wireless communication system. A terminal divides a terminal identifier into a first field, a second field, a third field and a fourth field and selects a first reference signal based on the first field and a maximum number of reference signals, a second reference signal based on the second field and the maximum number of reference signals, a third reference signal based on the third field and the maximum number of reference signals, and a fourth reference signal based on the fourth field and the maximum number of reference signals. Based on the first reference signal, the second reference signal, the third reference signal or the fourth reference signal, the terminal transmits contention-based data to a base station.

Provided are a method and a device for performing communication using a non-orthogonal code multiple access scheme in a wireless communication system. A terminal divides a terminal identifier into a first field, a second field, a third field and a fourth field and selects a first reference signal based on the first field and a maximum number of reference signals, a second reference signal based on the second field and the maximum number of reference signals, a third reference signal based on the third field and the maximum number of reference signals, and a fourth reference signal based on the fourth field and the maximum number of reference signals. Based on the first reference signal, the second reference signal, the third reference signal or the fourth reference signal, the terminal transmits contention-based data to a base station.

A subscriber unit and a method for receiving data at a subscriber unit for wireless communications are provided. A subscriber unit includes a receiver and at least one processor configured to monitor and receive forward control information within a first time interval of a first slot of a plurality of slots. Each slot of the plurality of slots includes the first time interval and a second time interval subsequent to the first time interval. The receiver and the at least one processor are further configured to receive forward traffic data in the first time interval of a second slot of the plurality of slots in accordance with the forward control information, where the second slot is contiguous to the first slot.