摘要:
Pilot, preamble and midamble patterns are provided that are particularly suited for four transmit antenna OFDM systems. Pilots are inserted in a scattered manner for each of the four antennas, either uncoded, space-time coded in pairs, space-time frequency coded in pairs, or space-time-frequency coded.
摘要:
Aspects of the invention include methods and devices for inserting data and pilot symbols into Orthogonal Frequency Division Multiplexing (OFDM) frames having a time domain and a frequency domain. A method involves inserting in at least one zone of a first type a two dimensional array of data and pilot symbols in time and frequency and inserting in at least one zone of a second type a two dimensional array of data and pilot symbols in time and frequency. In some implementations the zone of the first type comprises common pilot symbols that can be detected by all receivers receiving the OFDM frame. In some implementations the zone of the second type comprises dedicated pilot symbols that are only detectable by a receiver that is aware of pre-processing used to encode the dedicated pilot symbols. According to various embodiments of the invention, the zones of the first and second types can be partitioned in the OFDM frame based on time division multiplexing (TDM), frequency division multiplexing (FDM) or combined TDM/FDM. Examples of types of transmissions that could be transmitted in different zones of a single OFDM frame are OFDM multiple input multiple output (MIMO) transmissions and OFDM beam forming transmissions.
摘要:
A method and system for wireless frequency division multiple access communications in the uplink and/or downlink directions, having an improved pilot insertion scheme for single carrier based communications is provided. A first time duration for transmission of a data payload block (7) is established, and the transmission is processed using a first frequency domain or a time domain. A second time duration for transmission of at least one pilot block (70) is established, and the transmission is processed using a second frequency domain or the time domain, the second time duration (70) is not greater than the first time duration (7).
摘要:
A method and system for wireless data communication using a first wireless communication technology and a second wireless communication technology. The second wireless communication technology being different from the first wireless communication technology. A transmitter is arranged to transmit data using frame structures based on the first wireless communication technology and the second wireless communication technology in which the frame structure based on the second wireless communication technology has a timing structure, MAC and pilot that are also used with the frame structure of the first wireless communication technology. The transmitter is arranged to selectively change transmission on a frame by frame basis between the first wireless communication technology and the second wireless communication technology.
摘要:
The present invention provides a preamble that is inserted into an OFDMA frame and has a common sequence for all the base stations participating in a transmission. The subscriber station performs fine synchronization using the common sequence on the common preamble, and the resulting peaks will provide the locations of candidate base stations. The base station specific search is then performed in the vicinities of those peaks by using base station specific pseudo-noise sequences. With this two stage cell search, the searching window is drastically reduced. The preamble is matched to known values by a respective receiver to decode the signals and permit multiple signals to be transferred from the transmitter to the receiver. The preamble may comprise two parts, Preamble-1 and Preamble-2, which may be used in different systems, including multioutput, multi-input (MIMO) systems.
摘要:
Methods and apparatus are provided for inserting data symbols and pilot symbols in an OFDM (orthogonal frequency division multiplexing) transmission resource utilizing frequency hopping patterns for the data symbols and/or the pilot symbols. Data symbols and pilot symbols are allocated for down link (base station to mobile station) and up link (mobile station to bases station) transmission resources in a two-dimensional time-frequency pattern. For each antenna of a MIMO-OFDM (multiple input multiple output OFDM) communication system, pilot symbols are inserted in a scattered pattern in time-frequency and data symbols are inserted in an identical frequency-hopping pattern in time-frequency as that of other antennas.
摘要:
The present invention relates to soft handoffs in an OFDM system. Each mobile terminal measures pilot signal strengths of transmissions from adjacent base stations. If the pilot signal strength for a base station exceeds the defined threshold, that base station is added to an active set list. Each mobile terminal notifies the base stations of their active set lists. By providing the set list to the base station controller and the servicing base station, the mobile terminal identifies the sole servicing base station or triggers a soft handoff mode when multiple base stations appear on the active set list. The soft handoff mode uses a combination of scheduling and space-time coding to affect efficient and reliable handoffs.
摘要:
Methods and systems for signal transmission in millimeter wave (mmW) range. A set of sequences is used to encode a data signal for one layer in a group of layers. Each sequence in the set of sequences has a length equal to the number of resources shared among the group of layers. At least a portion of the sequences have a low density of non-zero values, and the non-zero values are assigned to a subset of the shared resources. Each sequence assigns a non-zero value to at most one resource of the subset of shared resources, and all non-zero values assigned by all sequences have equal power amplitudes.
摘要:
Methods and systems are provided for use with wireless networks having one or more cell in which each cell includes a base station (BS), at least one relay station (RS) and at least one mobile station (MS). The at least one relay station can be used as an intermediate station for providing communication between the BS and MS. Methods are provided for an RS to initially access the network, access of the RS by MSs initially accessing the network, methods of allocating OFDM resources for communicating between the BS, RS and/or MS for example dividing transmission resources into uplink and downlink transmissions, and methods of inserting pilot symbols into transmission resources used by the RS. In some embodiments on the invention, the methods are consistent and/or can be used in conjunction with existing standards such as 802.16e.
摘要:
Methods and apparatus are provided for inserting data symbols and pilot symbols in an OFDM (orthogonal frequency division multiplexing) transmission resource utilizing frequency hopping patterns for the data symbols and/or the pilot symbols. Data symbols and pilot symbols are allocated for down link (base station to mobile station) and up link (mobile station to bases station) transmission resources in a two-dimensional time-frequency pattern. For each antenna of a MIMO-OFDM (multiple input multiple output OFDM) communication system, pilot symbols are inserted in a scattered pattern in time-frequency and data symbols are inserted in an identical frequency-hopping pattern in time-frequency as that of other antennas.