摘要:
Frame structures and transmission techniques for a wireless communication system are described. In one frame structure, a super-frame includes multiple outer-frames, and each outer-frame includes multiple frames, and each frame includes multiple time slots. The time slots in each super-frame are allocated for downlink and uplink and for different radio technologies (e.g., W-CDMA and OFDM) based on loading. Each physical channel is allocated at least one time slot in at least one frame of each outer-frame in the super-frame. An OFDM waveform is generated for each downlink OFDM slot and multiplexed onto the slot. A W-CDMA waveform is generated for each downlink W-CDMA slot and multiplexed onto the slot. A modulated signal is generated for the multiplexed W-CDMA and OFDM waveforms and transmitted on the downlink. Each physical channel is transmitted in bursts. The slot allocation and coding and modulation for each physical channel can change for each super-frame.
摘要:
Techniques for determining time of arrivals (TOAs) of signals in a wireless communication network are described. Each cell may transmit (i) synchronization signals on a set of contiguous subcarriers in the center portion of the system bandwidth and (ii) reference signals on different sets of non-contiguous subcarriers distributed across the system bandwidth. A UE may determine TOA for a cell based on multiple signals transmitted on different sets of subcarriers. The UE may perform correlation for a first signal (e.g., a synchronization signal) from the cell to obtain first correlation results for different time offsets. The UE may perform correlation for a second signal (e.g., a reference signal) from the cell to obtain second correlation results for different time offsets. The UE may combine the first and second correlation results and may determine the TOA for the cell based on the combined correlation results.
摘要:
Techniques are provided for performing hierarchical coding in a multi-antenna communication system (e.g., a SIMO, MISO, or MIMO system). At a transmitter, a base stream and an enhancement stream are coded and modulated separately to obtain first and second data symbol streams, respectively. The first data symbol stream is processed in accordance with a first spatial processing scheme (e.g., a transmit diversity or a spatial multiplexing scheme) to obtain a first set of symbol substreams. The second data symbol stream is processed in accordance with a second spatial processing scheme (e.g., transmit diversity or spatial multiplexing) to obtain a second set of symbol substreams. The first set of symbol substreams is combined (e.g., using time division multiplexing or superposition) with the second set of symbol substreams to obtain multiple transmit symbol streams for transmission from multiple transmit antennas. A receiver performs complementary processing to recover the base stream and enhancement stream.
摘要:
Techniques for managing interference in a wireless network are described. In an aspect, reduce interference requests and interference indicators may be used for interference management to enable operation in scenarios with dominant interferers. In one design, a terminal may receive a reduce interference request from a first base station requesting lower interference on specified time-frequency resources. The terminal may also receive an interference indicator conveying the interference observed by a second base station. The terminal may determine its transmit power based on the reduce interference request and the interference indicator. For example, the terminal may determine an initial transmit power based on the reduce interference request (or the interference indicator) and may adjust the initial transmit power based on the interference indicator (or the reduce interference request) to obtain its transmit power. The terminal may transmit data to a serving base station at the determined transmit power.
摘要:
Techniques for transmitting null pilots to support interference estimation in a wireless network are described. A null pilot is non-transmission on designated time-frequency resources by a cell or a cluster of cells supporting cooperative transmission to a UE. The received power of the null pilot from the cell or cluster of cells may be indicative of interference from other cells. In one design, a cell in the cluster may determine resources for sending a null pilot by the cell. The cell may transmit the null pilot (i.e., send no transmissions) on the resources to allow UEs to estimate out-of-cluster interference. Some or all cells in the cluster may transmit null pilots on the same resources. The cell may receive interference and channel information from the UE and may send data transmission to the UE based on the interference and/or channel information. Remaining cells in the cluster may reduce interference to the UE.
摘要:
A system involves a transmitting device (for example, a first wireless communication device) and a receiving device (for example, a second wireless communication device). In the receiving device, LLR (Log-Likelihood Ratio) values are stored into an LLR buffer. LLR bit width is adjusted as a function of packet size of an incoming transmission to reduce the LLR buffer size required and/or to prevent LLR buffer capacity from being exceeded. The receiver may use a higher performance demodulator in order to maintain performance despite smaller LLR bit width. In the transmitting device, encoder code rate is adjusted as a function of receiver LLR buffer capacity and packet size of the outgoing transmission such that receiver LLR buffer capacity is not exceeded. Any combination of receiver LLR bit width adjustment, demodulator selection, and encoder code rate adjustment can be practiced to reduce LLR buffer size required while maintaining performance.
摘要:
To avoid or reduce intra-cell interference, each sector of a cell is associated with a sector-specific set of system resources (e.g., subbands) and at least one non-overlapping common set of system resources. Each common set for each sector includes system resources observing little or no interference from at least one other sector in the cell. The channel condition for a terminal in a given sector x is ascertained based on forward and/or reverse link measurements for the terminal. The terminal is assigned system resources from a common set or a sector-specific set for sector x based on the terminal's channel condition. For example, if the terminal observes high interference from another sector y, then the terminal is assigned system resources from a common set that observes little or no interference from sector y. The techniques may be used for an OFDMA system that uses frequency hopping.
摘要:
Techniques for utilizing a capacity-based effective signal-to-noise ratio (SNR) to improve wireless communication are described herein. In an embodiment, a mobile terminal can determine the effective SNR from a forward link channel using pilot/data symbols. The mobile terminal can convey the effective SNR to a base station. In order to minimize transmission overhead, the mobile terminal can quantize the effective SNR prior to transmitting it to the base station. In another embodiment, the base station can determine the effective SNR from a reverse link. The base station can utilize the effective SNR to facilitate scheduling transmissions from the mobile terminal, transmitting power control commands to the mobile terminal, and determining a supporting data rate for the mobile terminal, for example. Suitable SNRs include constrained, unconstrained, average, and/or approximated effective SNRs. In addition, various filters, such as an averaging filter, can be utilized to further process the effective SNR.
摘要:
In an access point identifier configuration scheme, different procedures are used for configuring (e.g., updating) different types of access points. For example, the criteria used to determine which identifiers are to be assigned to mobile access points may be different than the criteria used to determine which identifiers are to be assigned to stationary access points.
摘要:
Providing for improved access communication for wireless systems is described herein. By way of example, wireless devices can employ wireless resource re-use in selecting a subset of access communication resources, to mitigate interference on uplink access requests. Re-use can be based on current network conditions, or on a type of base station facilitating the wireless communication. In some aspects, planned resource re-use can be facilitated by an access terminal. The access terminal requests neighboring or interfering network access points to reserve a set of resources for a serving access point. Reserved resources can be conveyed to the serving access point with an uplink access probe, to further mitigate interference.