Abstract: A method and apparatus for protecting high throughput (HT) stations (STAs) are disclosed. In one embodiment, a physical layer (PHY) legacy preamble transmitted by one STA is decoded by another STA that does not use a legacy preamble. In another embodiment, one STA is identified by another STA by using bits in the preamble of a packet to indicate which PHY type will be used in the remaining portion of the packet. In yet another embodiment, one STA sends ready-to-send (RTS)/clear-to-send (CTS) or CTS-to-self messages for reserving a medium in the presence of another STA of a different type than the one STA. In yet another embodiment, an access point (AP) transmits a beacon or an association message including a capability information element (IE) that indicates operation or support for a legacy preamble, HT STA preambles and a medium access control (MAC) packet transmission with HT protection mechanisms.

Abstract: A system and method for automatic gain control for a wireless transmit and receive unit in a time-slotted communications system includes initializing an automatic gain control loop, sampling a received signal, and estimating the power of the received signal. The estimated power of the received signal is compared with a reference power level and an error signal is generated based upon the difference between the estimated power and the reference power level. The error signals generated by a plurality of received signals are accumulated in an accumulator, and the value of the accumulator is looked up in a table to locate a control word for an attenuator. The control word is then passed to the attenuator to adjust the gain.

Abstract: A correct escape mechanism is determined according to interference type. Transmission is arranged so that interference may be measured at all time slots as needed to compute a measure of variance in interference in time slots. If the variance is above a predetermined value, time division duplex escape mechanisms are employed. If the variance is below a predetermined value, appropriate escape mechanisms are employed depending on whether the escape mechanism is being implemented during an uplink or downlink. Interference causing FDD WTUs may be handed over to carrier bands to control interference experienced by TDD users.

Abstract: A wireless digital communication system includes a base station in communication with a plurality of user equipment mobile terminals (UEs). The system prioritizes the forwarding of blocks of downlink data to designated ones of the UEs. The system employs adaptive modulation and coding (AM&C) to achieve improved radio resource utilization and provides optimum data rates for user services. Blocks of downlink (DL) data are received by the base station which requests downlink (DL) channel quality measurements only from those mobile terminals (UEs) with pending downlink transmissions. The UEs respond to the request by measuring and reporting DL channel quality to the base station, which then allocates resources such that the UEs will make best use of radio resources. The base station notifies the UEs of the physical channel allocation indicating the modulation/coding rate and allocated slots followed by transmission of blocks of downlink data which are transmitted to the UEs.

Abstract: A wireless communication system which comprises a plurality of base stations and a user equipment. Each base station transmits a common primary synchronization code (PSC) in a primary synchronization channel at a different timing within a system frame, and a midamble code in a broadcast channel. A transmitted power level of the PSC and midamble code are at a common fixed ratio for each base station. The user equipment (UE) is capable of conducting cell search and includes a receiver for receiving said PSCs, a signal power measuring device for measuring the power level of received PSCs and identifying a frame timing of received PSCs which exceed a power threshold, and a processor for analyzing data signals received in the primary synchronization channel associated with the PSC with the highest power level of the received PSCs with a threshold exceeding power level.

Abstract: A method and apparatus for selecting an antenna mapping in multiple-in/multiple-out (MIMO) enabled wireless communication networks. A candidate set of currently available antenna mappings is determined based upon measured long term channel conditions. An antenna mapping is selected from the candidate set, and the mapping is calibrated with a selected antenna mapping of a receiving wireless transmit/receive unit (WTRU). When the selected mappings are calibrated, packet data transmission begins. In an alternative embodiment, a calibration training frame (CTF) is used to calibrate multiple antenna mappings simultaneously or sequentially. Also disclosed are physical layer and medium access control layer frame formats for implementing antenna mapping selection according to the invention.

Abstract: A model for a wireless code division multiple access communication system is generated. A plurality of first snapshots is provided. Each first snapshot has a plurality of user equipments (UEs) and base stations. Locations of the UEs in each first snapshot vary between the first snapshots. For each first snapshot, that first snapshot is divided into an uplink and downlink snapshot. For the uplink snapshot, uplink resources are assigned to each UE and an uplink transmission power level is determined of that UE. Dropped and not admitted UEs are determined in the uplink snapshot. For the downlink snapshot, downlink resources are assigned to each UE. Dropped and not admitted UEs are determined in the downlink snapshot based on the assigned downlink resources. Statistics are gathered on a performance of the system using the determined dropped and not admitted UEs.

Abstract: A correct escape mechanism is determined according to interference type. Transmission is arranged so that interference may be measured at all time slots as needed to compute a measure of variance in interference in time slots. If the variance is above a predetermined value, time division duplex escape mechanisms are employed. If the variance is below a predetermined value, appropriate escape mechanisms are employed depending on whether the escape mechanism is being implemented during an uplink or downlink. Interference causing FDD WTUs may be handed over to carrier bands to control interference experienced by TDD users.

Abstract: A method and system for improving responsiveness in exchanging management and control frames in a wireless local area network are disclosed. An initiator sends a frame (action, management, control or data frame) to a responder. Upon correctly receiving the frame, the responder sends a response frame to the initiator instead of directly sending an acknowledgement (ACK) packet. The responder preferably accesses the wireless medium to send the response frame in a short inter-frame spacing (SIFS). With this scheme, a long delay associated with having to contend for the wireless medium to send the response frame is avoided and therefore, the responsiveness and timeliness of the feedback mechanism is significantly enhanced. The response frame may be piggybacked on or aggregated with another packet.

Abstract: A method for assigning physical channels to time slots in a hybrid wireless time division multiple access/code division multiple access communication system begins by providing physical channels for assignment. A set of time slots is provided for potential assignment. The set of time slots is arranged into a sequence based on a quality of each of the set of time slots. The provided physical channels are assigned to the time slots in a time slot order of the sequence.

Abstract: A wireless digital communication method for a plurality of user equipment mobile terminals (UEs) to communicate with a base station. Adaptive modulation and coding (AM&C) is used to achieve improved radio resource utilization and provide optimum data rates for user services. Blocks of downlink (DL) data are received by the base station which requests downlink DL channel quality measurements only from those mobile terminals (UEs) with pending downlink transmissions. The UEs respond to the request by measuring and reporting DL channel quality to the base station, which then allocates resources such that the UEs will make best use of radio resources. The base station notifies the UEs of the physical channel allocation indicating the modulation/coding rate and allocated slots followed by transmission of blocks of downlink data which are transmitted to the UEs.

Abstract: A preamble for a random access channel (RACH) transmission is provided by selecting one out of sixteen preamble signatures. Each of the sixteen preamble signatures having sixteen symbols. A code is produced based on the preamble sequence. The produced code is phase rotated to produce a preamble code.

Abstract: A peer-to-peer communication system using a direct link setup (DLS) is disclosed. A mobile station (STA) establishes a direct communication link with another STA by sending a message requesting a DLS to an access point (AP), (i.e., a centralized controller). The AP may accept or reject the DLS request based on channel measurements. If the DLS request is accepted, the DLS is established such that the STAs may directly communicate with each other. An established DLS connection may be torn down by the AP sending a message including a DLS teardown request to one of the STAs, or based on channel measurements. The system may be an Ad hoc network comprising a plurality of STAs without an AP where each STA maintains a database of one-hop and two-hop STAs, and establishes a direct link to other STAs after informing neighboring STAs of an intention to establish a direct communication link.

Abstract: A method and system for eliminating interference caused by hidden nodes is disclosed. An initiator control message is defined for an initiator, (typically a wireless station (STA)), in order to begin an aggregate frame exchange with at least one responder. The initiator control message includes information on the queue sizes at the initiator. A responder, (typically an access point (AP)), sets up the required protection for the transmission of data by the initiator based on information on the queue sizes indicated in a field of the initiator control message using a responder control message. Other STAs that receive the responder control message set parameters for a wireless medium access accordingly. In another embodiment, multiple receiver aggregate multi-poll (MMP) and power save aggregation descriptor (PSAD) control frames are configured for transmission by a non-AP STA to provide enhanced scheduling and mitigate hidden node problems.

Abstract: Physical channels of a new user service are to be assigned to a set of time slots in a hybrid time division multiple access/code division multiple access wireless communication system. The new user service physical channels are ordered based on a desired reception quality of each of the new user service physical channels. The new user service physical channels are assigned to the set of time slots based on the order and the time slot sequence.

Abstract: A time division duplex method for determining whether to initiate handover of a mobile unit from a serving base station to a target base station, the method comprises receiving the broadcast channel from the serving base station (BCHser); calculating the serving base station received signal code power (RSCPser); receiving the broadcast channel from the target base station (BCHtar); calculating the target base station received signal code power (RSCPtar); determining interference signal code power for the serving base station (ISCPser); determining interference signal code power for the target base station (ISCPtar); calculating RSCPser/ISCPser; calculating RSCPtar/ISCPtar; and determining whether RSCPser/ISCPser is less than RSCPtar/ISCPtar, and if so, commencing handover from the serving base station to the target base station.

Abstract: A TTD system implements dynamic link adaptation by adding or changing control information to notify the receiver which timeslots and codes are currently active and which timeslots should be avoided. The system synchronizes the transmitter and the receiver such that the receiver knows which timeslots and codes the transmitter has used to map the coded composite transport channel onto physical channels. The system attempts to avoid the timeslots which are experiencing transmission difficulties, while attempting to utilize the timeslots which are not experiencing transmission problems.

Abstract: A base station transmits access control signals on a periodic basis having a first transmission rate. The base station transmits access control modification signals at a second transmission rate higher than the first transmission rate. The user equipment transmits an access attempt signal. The access attempt signal requests the base station to permit the user equipment access to the channel. The user equipment receives the transmitted access control signals and access modification signals. A wait period is determined based on in part the received access control signals and access control modification signals. In response to an unsuccessful access attempt, the user equipment delays transmitting a subsequent access attempt signal for the wait period.

Abstract: One out of sixteen preamble signatures is selected. A code is produced based on the selected preamble signature. The produced code is phase rotated to produce a processed preamble signature signal. The processed preamble signature signal is used in processing the CDMA RACH signal and the CDMA RACH signal is used to access a CDMA system.

Abstract: A UE system implements dynamic link adaptation by adding or changing control information to notify a receiver which timeslots and codes are currently active and which timeslots should be avoided. The UE provides synchronization such that the receiver knows which timeslots and codes the UE has used to map the coded composite transport channel onto physical channels. The UE attempts to avoid the timeslots which are experiencing transmission difficulties, while attempting to utilize the timeslots which are not experiencing transmission problems.