Abstract: First audit information corresponding to a first set of log entries associated with a transformation performed on first data is obtained, where the first audit information includes a first commutative result produced by applying a commutative function to object identifiers associated with the first set of log entries. Second audit information corresponding to a second set of log entries associated with the transformation performed on second data is obtained, with the second data being a different representation of the first data and where the second audit information includes a second commutative result produced by applying the commutative function to object identifiers associated with the second set of log entries. The first commutative result is compared with the second commutative result to validate whether the second data matches the first data. One or more actions are performed depending on whether the second data is the successful transformation of the first data.

Abstract: Items within a data set can be redistributed to different partitions of a distributed data store according to modified hash values. A redistribution event may, in some embodiments, trigger the redistribution of a data set. Modified hash values for items in the data set may be generated according to a secondary hashing scheme to be used for identifying the location of a new partition to store the item instead of hash values based on current key values that identify a current partition that stores the item. Access can be provided to items based on the modified hash values to determine the new partition that stores the item after redistribution.

Abstract: A computing resource service provider may provide customers with access to various services provided by a set of service endpoints. During certain intervals of time increased network traffic may cause an increase in the consumption of computing resources of the set of service endpoints. A throttling trigger may be detected that may cause one or more routing devices to reroute network traffic to one or more lower tier routing devices. The lower tier routing devices may maintain throttling information and forward network traffic to the set of service endpoints.

Abstract: To broadcast different types of transmission having different tiers of coverage in a wireless broadcast network, each base station processes data for a wide-area transmission in accordance with a first mode (or coding and modulation scheme) to generate data symbols for the wide-area transmission and processes data for a local transmission in accordance with a second mode to generate data symbols for the local transmission. The first and second modes are selected based on the desired coverage for wide-area and local transmissions, respectively. The base station also generates pilots and overhead information for local and wide-area transmissions. The data, pilots, and overhead information for local and wide-area transmissions are multiplexed onto their transmission spans, which may be different sets of frequency subbands, different time segments, or different groups of subbands in different time segments. More than two different types of transmission may also be multiplexed and broadcast.

Abstract: To broadcast different types of transmission having different tiers of coverage in a wireless broadcast network, each base station processes data for a wide-area transmission in accordance with a first mode (or coding and modulation scheme) to generate data symbols for the wide-area transmission and processes data for a local transmission in accordance with a second mode to generate data symbols for the local transmission. The first and second modes are selected based on the desired coverage for wide-area and local transmissions, respectively. The base station also generates pilots and overhead information for local and wide-area transmissions. The data, pilots, and overhead information for local and wide-area transmissions are multiplexed onto their transmission spans, which may be different sets of frequency subbands, different time segments, or different groups of subbands in different time segments. More than two different types of transmission may also be multiplexed and broadcast.

Abstract: To broadcast different types of transmission having different tiers of coverage in a wireless broadcast network, each base station processes data for a wide-area transmission in accordance with a first mode (or coding and modulation scheme) to generate data symbols for the wide-area transmission and processes data for a local transmission in accordance with a second mode to generate data symbols for the local transmission. The first and second modes are selected based on the desired coverage for wide-area and local transmissions, respectively. The base station also generates pilots and overhead information for local and wide-area transmissions. The data, pilots, and overhead information for local and wide-area transmissions are multiplexed onto their transmission spans, which may be different sets of frequency subbands, different time segments, or different groups of subbands in different time segments. More than two different types of transmission may also be multiplexed and broadcast.

Abstract: To broadcast different types of transmission having different tiers of coverage in a wireless broadcast network, each base station processes data for a wide-area transmission in accordance with a first mode (or coding and modulation scheme) to generate data symbols for the wide-area transmission and processes data for a local transmission in accordance with a second mode to generate data symbols for the local transmission. The first and second modes are selected based on the desired coverage for wide-area and local transmissions, respectively. The base station also generates pilots and overhead information for local and wide-area transmissions. The data, pilots, and overhead information for local and wide-area transmissions are multiplexed onto their transmission spans, which may be different sets of frequency subbands, different time segments, or different groups of subbands in different time segments. More than two different types of transmission may also be multiplexed and broadcast.

Abstract: Techniques to derive a channel estimate using substantially fewer number of complex multiplications than with a brute-force method to derive the same channel estimate. In one method, an intermediate vector B is initially derived based on K sub-vectors of a vector ? for a channel frequency response estimate and at least two DFT sub-matrices for a DFT matrix {tilde over (W)}, where K>1. An intermediate matrix A for the DFT matrix {tilde over (W)} is also obtained. A least square channel impulse response estimate is then derived based on the intermediate vector B and the intermediate matrix A. In one implementation, the intermediate vector B is obtained by first computing DFTs of a matrix ?T×L, which is formed based on the vector ?, to provide a matrix GL×L. Inner products between the columns of a base DFT sub-matrix W1 and the rows of the matrix GL×L are then computed to obtain the entries of the intermediate vector B.

Abstract: According to the invention, quantization encoding is conducted using the probability density function of the source, enabling fixed, variable and adaptive rate encoding. To achieve adaptive encoding, an update is conducted with a new observation of the data source, preferably with each new observation of the data source. The current probability density function of the source is then estimated to produce codepoints to vector quantize the observation of the data source.

Abstract: Techniques to derive a channel estimate using substantially fewer number of complex multiplications than with a brute-force method to derive the same channel estimate. In one method, an intermediate vector B is initially derived based on K sub-vectors of a vector ? for a channel frequency response estimate and at least two DFT sub-matrices for a DFT matrix {tilde over (W)}, where K>1. An intermediate matrix A for the DFT matrix {tilde over (W)} is also obtained. A least square channel impulse response estimate is then derived based on the intermediate vector B and the intermediate matrix A. In one implementation, the intermediate vector B is obtained by first computing DFTs of a matrix ?T×L, which is formed based on the vector ?, to provide a matrix GL×L. Inner products between the columns of a base DFT sub-matrix W1 and the rows of the matrix GL×L are then computed to obtain the entries of the intermediate vector B.

Abstract: Techniques to derive a channel estimate using substantially fewer number of complex multiplications than with a brute-force method to derive the same channel estimate. In one method, an intermediate vector B is initially derived based on K sub-vectors of a vector {circumflex over (H)} for a channel frequency response estimate and at least two DFT sub-matrices for a DFT matrix {tilde over (W)}, where K>1. An intermediate matrix A for the DFT matrix {tilde over (W)} is also obtained. A least square channel impulse response estimate is then derived based on the intermediate vector B and the intermediate matrix A. In one implementation, the intermediate vector B is obtained by first computing DFTs of a matrix ?T×L, which is formed based on the vector {circumflex over (H)}, to provide a matrix GL×L. Inner products between the columns of a base DFT sub-matrix W1 and the rows of the matrix GL×L are then computed to obtain the entries of the intermediate vector B.

Abstract: Pilot and data transmission schemes for multi-antenna communication systems utilizing multi-carrier modulation are provided. Subband multiplexing is used to avoid interference resulting from transmitting multiple signals simultaneously from multiple antennas. M usable subbands are initially arranged to form multiple groups of subbands, with each group including a different subset of the usable subbands. Each of T transmit antennas is then assigned one or possibly more subband groups for pilot transmission and typically one subband group for data transmission. Pilot and data may then be transmitted from each antenna on the subbands assigned to that antenna for pilot and data transmission. For each transmit antenna, the transmit power for each assigned subband may be scaled higher such that all of the total transmit power available for the antenna is used for transmission. Pilot and/or data may be transmitted simultaneously from all T antennas on all usable subbands without causing mutual interference.

Abstract: Techniques are provided to support successive interference cancellation (SIC) receiver processing with selection diversity whereby each of NT transmit antennas may be turned on or off. One symbol stream may be transmitted from each transmit antenna. A SIC receiver recovers the transmitted symbol streams in a specific order. Up to NT! orderings are evaluated. For each ordering, NT post-detection SNRs are obtained for NT transmit antennas and used to determine NT data rates, where the data rate is zero if the post-detection SNR is worse than a minimum required SNR. An overall data rate is computed for each ordering based on the NT data rates. The ordering with the highest overall data rate is selected for use. Up to NT symbol streams are processed at the data rates for the selected ordering and transmitted. The transmitted symbol streams are recovered in accordance with the selected ordering.

Abstract: Methods, signals, devices, and systems are provided for secure access to a network from an external client. Requests for access to confidential data may be redirected from a target server to a border server, after which a secure sockets layer connection between the border server and the external client carries user authentication information. After the user is authenticated to the network, requests may be redirected back to the original target server. Web pages sent from the target server to the external client are scanned for non-secure URLs such as those containing “http://” and modified to make them secure. The target server and the border server utilize various combinations of secure and non-secure caches. Although tunneling, may be used, the extensive configuration management burdens imposed by virtual private networks are not required.

Abstract: Accordingly, a method and apparatus are provided to convert received content into a first stream and a second stream, to transmit said first stream using a first tone and to transmit said second stream using an orthogonal scheme. A layering scheme is used to transmit the base stream covering a smaller area and an enhanced stream is used to cover a large utilizing orthogonal scheme.

Abstract: To broadcast different types of transmission having different tiers of coverage in a wireless broadcast network, each base station processes data for a wide-area transmission in accordance with a first mode (or coding and modulation scheme) to generate data symbols for the wide-area transmission and processes data for a local transmission in accordance with a second mode to generate data symbols for the local transmission. The first and second modes are selected based on the desired coverage for wide-area and local transmissions, respectively. The base station also generates pilots and overhead information for local and wide-area transmissions. The data, pilots, and overhead information for local and wide-area transmissions are multiplexed onto their transmission spans, which may be different sets of frequency subbands, different time segments, or different groups of subbands in different time segments. More than two different types of transmission may also be multiplexed and broadcast.

Abstract: Techniques are provided to support successive interference cancellation (SIC) receiver processing with selection diversity whereby each of NT transmit antennas may be turned on or off. One symbol stream may be transmitted from each transmit antenna. A SIC receiver recovers the transmitted symbol streams in a specific order. Up to NT! orderings are evaluated. For each ordering, NT post-detection SNRs are obtained for NT transmit antennas and used to determine NT data rates, where the data rate is zero if the post-detection SNR is worse than a minimum required SNR. An overall data rate is computed for each ordering based on the NT data rates. The ordering with the highest overall data rate is selected for use. Up to NT symbol streams are processed at the data rates for the selected ordering and transmitted. The transmitted symbol streams are recovered in accordance with the selected ordering.

Abstract: Techniques to derive a channel estimate using substantially fewer number of complex multiplications than with a brute-force method to derive the same channel estimate. In one method, an intermediate vector B is initially derived based on K sub-vectors of a vector {circumflex over (H)} for a channel frequency response estimate and at least two DFT sub-matrices for a DFT matrix {tilde over (W)}, where K>1. An intermediate matrix A for the DFT matrix {tilde over (W)} is also obtained. A least square channel impulse response estimate is then derived based on the intermediate vector B and the intermediate matrix A. In one implementation, the intermediate vector B is obtained by first computing DFTs of a matrix ĤT×L, which is formed based on the vector {circumflex over (H)}, to provide a matrix GL×L. Inner products between the columns of a base DFT sub-matrix W1 and the rows of the matrix GL×L are then computed to obtain the entries of the intermediate vector B.

Abstract: Methods, signals, devices, and systems are provided for secure access to a network from an external client. Requests for access to confidential data may be redirected from a target server to a border server, after which a secure sockets layer connection between the border server and the external client carries user authentication information. After the user is authenticated to the network, requests may be redirected back to the original target server. Web pages sent from the target server to the external client are scanned for non-secure URLs such as those containing “http.//” and modified to make them secure. The target server and the border server utilize various combinations of secure and non-secure caches. Although tunneling, may be used, the extensive configuration management burdens imposed by virtual private networks are not required.

Abstract: Methods, signals, devices, and systems are provided for secure access to a network from an external client. Requests for access to confidential data may be redirected from a target server to a border server, after which a secure sockets layer connection between the border server and the external client carries user authentication information. After the user is authenticated to the network, requests may be redirected back to the original target server. Web pages sent from the target server to the external client are scanned for non-secure URLs such as those containing “http://” and modified to make them secure. The target server and the border server utilize various combinations of secure and non-secure caches. Although tunneling may be used, the extensive configuration management burdens imposed by virtual private networks are not required.