Abstract:
Techniques for managing peak-to-average power ratio (PAPR) for multi-carrier modulation in wireless communication systems. Different terminals in a multiple-access system may have different required transmit powers. The number of carriers to allocate to each terminal is made dependent on its required transmit power. Terminals with higher required transmit powers may be allocated fewer carriers (associated with smaller PAPR) to allow the power amplifier to operate at higher power levels. Terminals with lower required transmit powers may be allocated more carriers (associated with higher PAPR) since the power amplifier is operated at lower power levels. The specific carriers to assign to the terminals may also be determined by their transmit power levels to reduce out-of-band emissions. Terminals with higher required transmit powers may be assigned with carriers near the middle of the operating band, and terminals with lower required transmit powers may be assigned with carriers near the band edges.
Abstract:
Providing for interference reduction and/or avoidance utilizing backhaul signaling between wireless access points (APs) of a wireless access network (AN) is described herein. By way of example, an interference avoidance request (IAR) can be issued by an AP to reduce signal interference on forward link (FL) and/or downlink (DL) transmissions by neighboring APs. The IAR can be routed via a backhaul network and/or over-the-air via access terminals (ATs) coupled with the AP or one or more interfering APs. Upon receiving the IAR, an interfering AP can determine reduced transmit power levels for FL and/or RL transmissions and respond to the IAR. The response can include reduced power levels and can be sent via the backhaul network or OTA. By employing the backhaul network in full or in part, interference avoidance can be conducted even for semi-planned or unplanned heterogeneous networks coupled by the backhaul.
Abstract:
Techniques for mitigating interference in a wireless communication network are described. A terminal may desire to communicate with a weaker serving base station and may observe high interference from a strong interfering base station. The two base stations may be asynchronous and have different frame timing. In an aspect, high interference may be mitigated by having the interfering base station reserve downlink and/or uplink resources. The interfering base station may transmit at a low power level or not at all on the reserved downlink resources to reduce interference to the terminal. Terminals served by the interfering base station may transmit at a low power level or not at all on the reserved uplink resources to reduce interference at the serving base station. The terminal may then be able to communicate with the serving base station.
Abstract:
To reduce inter-sector interference for “weak” users and combat a potentially large variation in interference levels observed by “strong” and weak users, system resources (e.g., frequency subbands) available for data transmission in a system are partitioned into multiple (e.g., three) disjoint sets. Each sector in the system is assigned one subband set. Neighboring sectors are assigned different subband sets such that the subband set assigned to each sector is orthogonal to the subband sets assigned to neighboring sectors. Each sector has an assigned subband set and an unassigned subband set, which contains all subbands not in the assigned set. Weak users in each sector (which are typically strong interferers to neighboring sectors) are allocated subbands in the assigned set. Strong users in each sector are allocated subbands in the unassigned set. The weak users in each sector are then orthogonal to strong interferers in neighboring sectors.
Abstract:
Systems and methodologies are described that facilitate defining new control channels in legacy wireless networks. Control data resources for new systems can be defined over resources reserved for general data communications in the legacy wireless network specification. In this regard, legacy devices can still be supported by devices implementing new control data resources, and the new control data resources can avoid substantial interference that is typically exhibited over legacy control and/or reference signal resources by instead using the general data resources. In addition, new system devices can avoid scheduling data communication resources over the new control resources to create a substantially non-interfered global control segment. Control data can be transmitted over the segment using beacon-based technologies, reuse schemes, and/or the like.
Abstract:
Methods and apparatuses that apply a time-varying delay to symbols to be transmitted from one or more antennas are provided. In a first embodiment, first and second transmission orders for samples in first and second data symbols, respectively, are determined. First and second cyclic prefixes are appended to the beginnings of the first and second transmission orders, respectively. The first and second data symbols are then provided to the same antenna for transmissions beginning at different time slots in accordance with a delay diversity scheme. In a second embodiment, either the first data symbol or the second data symbol can be provided to different antennas for transmissions beginning at different time slots in accordance with a delay diversity scheme.
Abstract:
Systems and methodologies are described that facilitate power headroom management in a wireless communication system. As described herein, a predefined relationship between locations along a system frequency band and corresponding power backoff parameters is utilized to minimize spurious emissions outside the system frequency band and/or excessive interference by, for example, associating locations near one or more edges of the permitted frequency band with substantially high power backoff parameters. As further described herein, the predefined relationship can be known a priori to the base station and the mobile terminal.
Abstract:
Systems and methodologies are described that facilitate providing high reuse for transmitting reference signals, such as positioning reference signals (PRS) and cell-specific reference signals (CRS), to improve hearability thereof for applications such as trilateration and/or the like. In particular, PRSs can be transmitted in designated or selected positioning subframes. Resource elements within the positioning subframe can be selected for transmitting the PRSs and can avoid conflict with designated control regions, resource elements used for transmitting cell-specific reference signals, and/or the like. Resource elements for transmitting PRSs can be selected according to a planned or pseudo-random reuse scheme. In addition, a transmit diversity scheme can be applied to the PRSs to minimize impact of introducing the PRSs to legacy devices. Moreover, portions of a subframe not designated for PRS transmission can be utilized for user plane data transmission.
Abstract:
Method and apparatus for estimating reverse link loading in a wireless communication system. The reverse link interference is measured and reverse link receiver noise is measured. The reverse link interference is compared to the reverse link receiver noise, for example, by dividing the interference power by the receiver noise power. The reverse link receiver noise can be measured in an orthogonal frequency division multiple access (OFDMA) system by nulling transmission from access terminals within the cell and nearby during a null time and frequency interval. Power measure in the null time and frequency interval is receiver noise power. The reverse link interference can be measure by several means. For example, local null time and frequency intervals can be designated. The access terminals within the cell null their transmissions during the local time and frequency intervals. Access terminals outside the cell continue to transmit during the local time and frequency intervals. Power measured in the local time and frequency interval is interference power. As another example, interference power can be measured by subtracting pairs of pilot symbols that are contiguous to each other in time or frequency.
Abstract:
A method to mitigate interference in a wireless system is provided. The method includes processing a set of radio network identifiers and limiting a number of hypotheses associated with the radio network identifiers in order to mitigate interference in a wireless network. In another aspect, the method includes processing a set of hypotheses and limiting the set of hypotheses by limiting a number of downlink grants to a common space, limiting the number of downlink grants to a number of instances, or limiting the number of grants to a physical downlink control channel (PDCCH) type. In yet another aspect, the method includes processing a downlink set and generating a target termination level for the downlink data set, the termination level associated with a Hybrid automatic repeat-request.