# US 8,570,982 B2 · Transmit spatial diversity for cellular single frequency networks > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,570,982 B2 - Document ID: US8570982B2 - Status: Granted - Kind: B2 - Application number: 12/873,551 - Filed: 2010-09-01 - Published: 2010-12-23 - Granted: 2013-10-29 - Earliest claimed: 2005-06-14 - Assignees: QUALCOMM Incorporated - Applicants: Durga Prasad Malladi - Inventors: Durga Prasad Malladi - Web page: https://patentgrep.com/patent/US8570982B2 ## CPC - H04B 7/022: Site diversity; Macro-diversity (using two or more spaced independent antennas H04B7/04) - H04B 7/0491: using two or more sectors, i.e. sector diversity - H04L 1/0625: {Transmitter arrangements} - H04L 1/0656: {Cyclotomic systems, e.g. Bell Labs Layered Space-Time [BLAST]} - H04L 27/3488: {Multiresolution systems} - H04B 7/0667: {of delayed versions of same signal (using space-time coding H04L1/0618)} - H04B 7/0691: {using subgroups of transmit antennas} - H04B 7/0848: {Joint weighting} - H04L 1/0002: {by adapting the transmission rate} - H04B: TRANSMISSION - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Multiple-In Multiple-Out (MIMO) techniques are used to increase spectral efficiency of a cellular single frequency network. In some embodiments with single transmit antenna per cell, multiple data streams are transmitted from multiple cells, one data stream per set of transmit antennae. The mapping of streams to antenna sets is permuted in time. In this way, user equipment devices (UEs) at cell edges benefit from MIMO, and UEs near cell centers benefit from high carrier-to-interference (C/I) ratio of the signal. In some embodiments, each stream is concurrently transmitted on base layer of a hierarchically modulated signal from one set, and on enhancement layer of a hierarchically modulated signal from another set. The mapping of sets to streams is permuted in time. The UEs at cell edges benefit from MIMO, and the UEs near cell centers benefit from the high C/I to decode both streams from the base and enhancement layers. ## Claims ### Claim 1 A method for transmitting data in a cellular communications system with transmit spatial diversity, the method comprising: selecting at least one antenna from each sector of a plurality of sectors to form a transmit antenna set of a plurality of L transmit antenna sets, wherein L is an integer greater than one; assigning for a first period, each of a plurality of L data streams to a first different transmit antenna set of the plurality of L transmit antenna sets, resulting in a first distribution of data streams among transmit antenna sets; concurrently transmitting to a plurality of receivers during the first period, each of the plurality of L data streams through transmit antennae of the plurality of L transmit antenna sets according to the first distribution so that transmit antennae of said each transmit antenna set transmit during the first period the data stream assigned to said each transmit antenna set for the at least one first period; assigning for a second period, each of the plurality of L data streams to a second different transmit antenna set of the plurality of L transmit antenna sets, resulting in a second distribution of data streams among transmit antenna sets, wherein the second distribution is different from the first distribution; and concurrently transmitting to the plurality of receivers during the second period, each of the plurality of L data streams through the transmit antennae of the plurality of L transmit antenna sets according to the second distribution so that transmit antennae of said each transmit antenna set transmit during the second period the data stream assigned to said each transmit antenna set for the second period. ### Claim 2 (depends on 1) The method of claim 1, further comprising: modulating each of the plurality of L data streams with identical modulation and code set (MCS) combinations prior to transmission. ### Claim 3 (depends on 1) The method of claim 1, wherein: L is equal to two; the first period comprises a plurality of first subperiods; the second period comprises a plurality of second subperiods; and during a first time duration, the plurality of first subperiods are interleaved with the plurality of second subperiods. ### Claim 4 (depends on 3) The method of claim 3, wherein a first data stream and a second data stream of the plurality of L data streams are multicast or broadcast on at least one common channel. ### Claim 5 (depends on 1) The method of claim 1, wherein the cellular communications system supports single frequency network (SFN) operation and orthogonal frequency division multiplexing (OFDM) transmissions. ### Claim 6 (depends on 5) The method of claim 5, wherein each transmit antenna of the plurality of L transmit antenna sets uses a distinct pilot sub-carrier. ### Claim 7 A method for receiving data in a cellular communications system with transmit spatial diversity, the method comprising: receiving a plurality of signals comprising a plurality of L data streams transmitted from a plurality of L transmit antenna sets based on a distribution of data streams among transmit antenna sets, wherein each of the plurality of L data streams has been concurrently transmitted by a first different transmit antenna set comprising a first distribution of transmit antennae from the plurality of L transmit antenna sets so that transmit antennae of said each transmit antenna set transmit during a first period the data stream assigned to said each transmit antenna set for the first period and concurrently transmitted by a second different transmit antenna set comprising a second distribution of transmit antennae from the plurality of L transmit antenna sets so that transmit antennae of said each transmit antenna set transmit during a second period the data stream assigned to said each transmit antenna set for the second period; deriving a channel estimate for each of the plurality of signals to obtain channel estimates; and separating each of the plurality of L data streams from the plurality of signals using the channel estimates to generate a plurality of separated L data streams. ### Claim 8 (depends on 7) The method of claim 7, wherein the channel estimates comprise a composite channel frequency response for each transmit antenna of the plurality of L transmit antenna sets, and is derived using a minimum mean square error (MMSE) or low-complexity zero-forced robust MMSE solution. ### Claim 9 (depends on 7) The method of claim 7, further comprising: decoding each of the plurality of separated L data streams. ### Claim 10 (depends on 9) The method of claim 9, further comprising: performing successive interference cancellation (SIC) on the plurality of separated L data streams to generate a plurality of interference-cancelled separated L data streams if the decoding is unsuccessful; and further decoding each of the plurality of interference-cancelled separated L data streams. ### Claim 11 An apparatus for transmitting data in a cellular communications system with transmit spatial diversity, the apparatus comprising: means for selecting at least one antenna from each sector of a plurality of sectors to form a transmit antenna set of a plurality of L transmit antenna sets, wherein L is an integer greater than one; means for assigning for a first period, each of a plurality of L data streams to a first different transmit antenna set of the plurality of L transmit antenna sets, resulting in a first distribution of data streams among transmit antenna sets; means for concurrently transmitting to a plurality of receivers during the first period, each of the plurality of L data streams from the first through transmit antennae of the plurality of L transmit antenna sets according to the first distribution so that transmit antennae of said each transmit antenna set transmit during the first period the data stream assigned to said each transmit antenna set for the at least one first period; means for assigning for a second period, each of the plurality of L data streams to a second different transmit antenna set of the plurality of L transmit antenna sets, resulting in a second distribution of data streams among transmit antenna sets, wherein the second distribution is different from the first distribution; and means for concurrently transmitting to the plurality of receivers during the second period, each of the plurality of L data streams through the transmit antennae of the plurality of L transmit antenna sets according to the second distribution so that transmit antennae of said each transmit antenna set transmit during the second period the data stream assigned to said each transmit antenna set for the second period. ### Claim 12 (depends on 11) The apparatus of claim 11, further comprising: means for modulating each of the plurality of L data streams with identical modulation and code set (MCS) combinations prior to transmission. ### Claim 13 (depends on 11) The apparatus of claim 11, wherein: L is equal to two; the first period comprises a plurality of first subperiods; the second period comprises a plurality of second subperiods; and during a first time duration, the plurality of first subperiods are interleaved with the plurality of second subperiods. ### Claim 14 (depends on 13) The apparatus of claim 13, wherein a first data stream and a second data stream of the plurality of L data streams are multicast or broadcast on at least one common channel. ### Claim 15 (depends on 11) The apparatus of claim 11, wherein the cellular communications system supports single frequency network (SFN) operation and orthogonal frequency division multiplexing (OFDM) transmissions. ### Claim 16 (depends on 15) The apparatus of claim 15, wherein each transmit antenna of the plurality of L transmit antenna sets uses a distinct pilot sub-carrier. ### Claim 17 An apparatus for receiving data in a cellular communications system with transmit spatial diversity, the apparatus comprising: means for receiving a plurality of signals comprising a plurality of L data streams transmitted from a plurality of L transmit antenna sets based on a distribution of data streams among transmit antenna sets, wherein each of the plurality of L data streams has been concurrently transmitted by a first different transmit antenna set comprising a first distribution of transmit antennae from the plurality of L transmit antenna sets so that transmit antennae of said each transmit antenna set transmit during a first period the data stream assigned to said each transmit antenna set for the first period and concurrently transmitted by a second different transmit antenna set comprising a second distribution of transmit antennae from the plurality of L transmit antenna sets so that transmit antennae of said each transmit antenna set transmit during a second period the data stream assigned to said each transmit antenna set for the second period; means for deriving a channel estimate for each of the plurality of signals to obtain channel estimates; and means for separating each of the plurality of L data streams from the plurality of signals using the channel estimates to generate a plurality of separated L data streams. ### Claim 18 (depends on 17) The apparatus of claim 17, wherein the channel estimates comprise a composite channel frequency response for each transmit antenna of the plurality of L transmit antenna sets, and is derived using a minimum mean square error (MMSE) or low-complexity zero-forced robust MMSE solution. ### Claim 19 (depends on 17) The apparatus of claim 17, further comprising: means for decoding each of the plurality of separated L data streams. ### Claim 20 (depends on 19) The apparatus of claim 19, further comprising: means for performing successive interference cancellation (SIC) on the plurality of separated L data streams to generate a plurality of interference-cancelled separated L data streams if the decoding is unsuccessful; and means for further decoding each of the plurality of interference-cancelled separated L data streams. ### Claim 21 An apparatus for transmitting data in a cellular communications system with transmit spatial diversity, the apparatus comprising: a processor configured for: selecting at least one antenna from each sector of a plurality of sectors to form a transmit antenna set of a plurality of L transmit antenna sets, wherein L is an integer greater than one; assigning for a first period, each of a plurality of L data streams to a first different transmit antenna set of the plurality of L transmit antenna sets, resulting in a first distribution of data streams among transmit antenna sets; concurrently transmitting to a plurality of receivers during the first period, each of the plurality of L data streams through transmit antennae of the plurality of L transmit antenna sets according to the first distribution so that transmit antennae of said each transmit antenna set transmit during the first period the data stream assigned to said each transmit antenna set for the at least one first period; assigning for a second period, each of the plurality of L data streams to a second different transmit antenna set of the plurality of L transmit antenna sets, resulting in a second distribution of data streams among transmit antenna sets, wherein the second distribution is different from the first distribution; and concurrently transmitting to the plurality of receivers during the second period, each of the plurality of L data streams through the transmit antennae of the plurality of L transmit antenna sets according to the second distribution so that transmit antennae of said each transmit antenna set transmit during the second period the data stream assigned to said each transmit antenna set for the second period; and a memory coupled to the processor. ### Claim 22 (depends on 21) The apparatus of claim 21, wherein the processor is further configured for: modulating each of the plurality of L data streams with identical modulation and code set (MCS) combinations prior to transmission. ### Claim 23 (depends on 21) The apparatus of claim 21, wherein: L is equal to two; the first period comprises a plurality of first subperiods; the second period comprises a plurality of second subperiods; and during a first time duration, the plurality of first subperiods are interleaved with the plurality of second subperiods. ### Claim 24 (depends on 23) The apparatus of claim 23, wherein a first data stream and a second data stream of the plurality of L data streams are multicast or broadcast on at least one common channel. ### Claim 25 (depends on 21) The apparatus of claim 21, wherein the cellular communications system supports single frequency network (SFN) operation and orthogonal frequency division multiplexing (OFDM) transmissions. ### Claim 26 (depends on 25) The apparatus of claim 25, wherein each transmit antenna of the plurality of L transmit antenna sets uses a distinct pilot sub-carrier. ### Claim 27 An apparatus for receiving data in a cellular communications system with transmit spatial diversity, the apparatus comprising: a radio network transceiver for receiving a plurality of signals comprising a plurality of L data streams transmitted from a plurality of L transmit antenna sets based on a distribution of data streams among transmit antenna sets, wherein each of the plurality of L data streams has been concurrently transmitted by a first different transmit antenna set comprising a first distribution of transmit antennae from the plurality of L transmit antenna sets so that transmit antennae of said each transmit antenna set transmit during a first period the data stream assigned to said each transmit antenna set for the first period and concurrently transmitted by a second different transmit antenna set comprising a second distribution of transmit antennae from the plurality of L transmit antenna sets so that transmit antennae of said each transmit antenna set transmit during a second period the data stream assigned to said each transmit antenna set for the second period; and a processor for deriving a channel estimate for each of the plurality of signals to obtain channel estimates, and for separating each of the plurality of L data streams from the plurality of signals using the channel estimates to generate a plurality of separated L data streams. ### Claim 28 (depends on 27) The apparatus of claim 27, wherein the channel estimates comprise a composite channel frequency response for each transmit antenna of the plurality of L transmit antenna sets, and is derived using a minimum mean square error (MMSE) or low-complexity zero-forced robust MMSE solution. ### Claim 29 (depends on 27) The apparatus of claim 27, further comprising: a decoder for decoding each of the plurality of separated L data streams. ### Claim 30 (depends on 29) The apparatus of claim 29, wherein the processor is further configured for performing successive interference cancellation (SIC) on the plurality of separated L data streams to generate a plurality of interference-cancelled separated L data streams if the decoding is unsuccessful; and wherein the decoder is further configured for further decoding each of the plurality of interference-cancelled separated L data streams. ### Claim 31 A computer-readable medium storing a computer program, wherein execution of the computer program is for: selecting at least one antenna from each sector of a plurality of sectors to form a transmit antenna set of a plurality of L transmit antenna sets, wherein L is an integer greater than one; assigning for a first period, each of a plurality of L data streams to a first different transmit antenna set of the plurality of L transmit antenna sets, resulting in a first distribution of data streams among transmit antenna sets, wherein each of the plurality of L data streams are partitions of the data; concurrently transmitting to a plurality of receivers during the first period, each of the plurality of L data streams through transmit antennae of the plurality of L transmit antenna sets according to the first distribution so that transmit antennae of said each transmit antenna set transmit during the first period the data stream assigned to said each transmit antenna set for the at least one first period; assigning for a second period, each of the plurality of L data streams to a second different transmit antenna set of the plurality of L transmit antenna sets, resulting in a second distribution of data streams among transmit antenna sets, wherein the second distribution is different from the first distribution; and concurrently transmitting to the plurality of receivers during the second period, each of the plurality of L data streams through the transmit antennae of the plurality of L transmit antenna sets according to the second distribution so that transmit antennae of said each transmit antenna set transmit during the second period the data stream assigned to said each transmit antenna set for the second period. ### Claim 32 (depends on 31) The computer-readable medium of claim 31, wherein execution of the computer program is also for: modulating each of the plurality of L data streams with identical modulation and code set (MCS) combinations prior to transmission. ### Claim 33 (depends on 31) The computer-readable medium of claim 31, wherein: L is equal to two; the first period comprises a plurality of first subperiods; the second period comprises a plurality of second subperiods; and during a first time duration, the plurality of first subperiods are interleaved with the plurality of second subperiods. ### Claim 34 (depends on 33) The computer-readable medium of claim 33, wherein a first data stream and a second data stream of the plurality of L data streams are multicast or broadcast on at least one common channel. ### Claim 35 (depends on 31) The computer-readable medium of claim 31, wherein the cellular communications system supports single frequency network (SFN) operation and orthogonal frequency division multiplexing (OFDM) transmissions. ### Claim 36 (depends on 35) The computer-readable medium of claim 35, wherein each transmit antenna of the plurality of L transmit antenna sets uses a distinct pilot sub-carrier. ### Claim 37 A computer-readable medium storing a computer program, wherein execution of the computer program is for: receiving a plurality of signals comprising a plurality of L data streams transmitted from a plurality of L transmit antenna sets based on a distribution of data streams among transmit antenna sets, wherein each of the plurality of L data streams has been concurrently transmitted by a first different transmit antenna set comprising a first distribution of transmit antennae from the plurality of L transmit antenna sets so that transmit antennae of said each transmit antenna set transmit during a first period the data stream assigned to said each transmit antenna set for the first period and concurrently transmitted by a second different transmit antenna set comprising a second distribution of transmit antennae from the plurality of L transmit antenna sets so that transmit antennae of said each transmit antenna set transmit during a second period the data stream assigned to said each transmit antenna set for the second period; deriving a channel estimate for each of the plurality of signals to obtain channel estimates; and separating each of the plurality of L data streams from the plurality of signals using the channel estimates to generate a plurality of separated L data streams. ### Claim 38 (depends on 37) The computer-readable medium of claim 37, wherein the channel estimates comprise a composite channel frequency response for each transmit antenna of the plurality of L transmit antenna sets, and is derived using a minimum mean square error (MMSE) or low-complexity zero-forced robust MMSE solution. ### Claim 39 (depends on 37) The computer-readable medium of claim 37, wherein execution of the computer program is also for: decoding each of the plurality of separated L data streams. ### Claim 40 (depends on 39) The computer-readable medium of claim 39, wherein execution of the computer program is also for: performing successive interference cancellation (SIC) on the plurality of separated L data streams to generate a plurality of interference-cancelled separated L data streams if the decoding is unsuccessful; and further decoding each of the plurality of interference-cancelled separated L data streams.