# US 7,610,024 B2 · Methods and apparatus of providing transmit and/or receive diversity with multiple antennas in wireless communication systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,610,024 B2 - Document ID: US7610024B2 - Status: Granted - Kind: B2 - Application number: 11/284,285 - Filed: 2005-11-21 - Published: 2006-05-11 - Granted: 2009-10-27 - Earliest claimed: 2003-10-16 - Assignees: QUALCOMM Incorporated - Inventors: Rajiv Laroia; Junyi Li; Sundeep Rangan; Murari Srinivasan; Frank A. Lane; Prashanth Hande - Web page: https://patentgrep.com/patent/US7610024B2 ## CPC - H04B 7/0604: {with predefined switching scheme} - H01Q 3/24: varying the orientation by switching energy from one active radiating element to another, e.g. for beam switching - H01Q 3/2605: {Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays} - H04B 7/0691: {using subgroups of transmit antennas} - H04L 5/0026: {Division using four or more dimensions, e.g. beam steering or quasi-co-location [QCL]} - H04W 52/42: in systems with time, space, frequency or polarisation diversity - H04B 7/061: {using feedback from receiving side} - H04B 7/0805: {with single receiver and antenna switching (H04B7/0822 takes precedence)} - H04L 1/0026: {Transmission of channel quality indication} - H04L 5/0007: {the frequencies being orthogonal, e.g. OFDM(A) or DMT} - H04L 5/0023: {Time-frequency-space} - H04L 5/006: {Quality of the received signal, e.g. BER, SNR, water filling} - H04B: TRANSMISSION - H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Transmit and/or receive diversity is achieved using multiple antennas. In some embodiments, a single transmitter chain within a wireless terminal is coupled over time to a plurality of transmit antennas. At any given time, a controllable switching module couples the single transmitter chain to one the plurality of transmit antennas. Over time, the switching module couples the output signals from the single transmitter chain to different transmit antennas. Switching decisions are based upon predetermined information, dwell information, and/or channel condition feedback information. Switching is performed on some dwell and/or channel estimation boundaries. In some OFDM embodiments, each of multiple transmitter chains is coupled respectively to a different transmit antenna. Information to be transmitted is mapped to a plurality of tones. Different subsets of tones are formed for and transmitted through different transmit chain/antenna sets simultaneously. The balance of tones allocated to the subsets for each antenna are changed as a function of predetermined information, dwell information, and/or channel condition feedback information. ## Claims ### Claim 1 A wireless terminal for use in a communication system including a base station, the wireless terminal comprising: a transmitter signal processing chain including a switching module for coupling said transmitter chain to a plurality of antenna elements, said switching module configured to perform switching on signal boundaries corresponding to base station channel estimation memory reset points but not in between, said plurality of antenna elements including at least a first antenna element and a second antenna element each of which can be used independently; and a switching control module configured to control the switching module during a first period of time to switch between said first and second antenna elements on at least some signal boundaries corresponding to base station channel estimation memory reset points which occur during said first period of time to thereby change the antenna element used to transmit signals from said transmitter signal processing chain, each switch, during said first period of time, being preceded and followed by at least one dwell, a dwell being a period of time during which said wireless terminal uses a single set of tones to transmit signals to said base station, a different set of tones being used in immediately consecutive dwells during said first period of time. ### Claim 2 (depends on 1) The wireless terminal of claim 1, wherein said switching module switches between said first and second antenna elements according to a predetermined switching sequence. ### Claim 3 (depends on 1) The wireless terminal of claim 1, wherein said transmitter signal processing chain is an orthogonal frequency division multiplexing (OFDM) signal processing chain. ### Claim 4 A wireless terminal for use in a communication system including a base station, the wireless terminal comprising: a transmitter signal processing chain including switching means for coupling said transmitter chain to a plurality of antenna elements, said switching means switching on signal boundaries corresponding to base station channel estimation memory reset points but not in between, said plurality of antenna elements including at least a first antenna element and a second antenna element each of which can be used independently; and switching control means for controlling the switching means during a first period of time to switch between said first and second antenna elements on at least some signal boundaries corresponding to base station channel estimation memory reset points which occur during said first period of time to thereby change the antenna element used to transmit signals from said single transmitter signal processing chain, each switch during said first period of time being preceded and followed by at least one dwell, a dwell being a period of time during which said wireless terminal uses a single set of tones to transmit signals to said base station, a different set of tones being used in immediately consecutive dwells during said first period of time. ### Claim 5 (depends on 4) The wireless terminal of claim 4, wherein said switching means switches between said first and second antenna elements according to a predetermined switching sequence. ### Claim 6 (depends on 4) The wireless terminal of claim 4, wherein said transmitter signal processing chain is an orthogonal frequency division multiplexing (OFDM) signal processing chain. ### Claim 7 A computer readable medium including machine executable instructions, for use in a wireless terminal in a communication system including a base station, said wireless terminal including a transmitter signal processing chain including a switching module for coupling said single transmitter chain to a plurality of antenna elements, the computer readable medium comprising: instructions for causing said switching module to perform switching on signal boundaries corresponding to base station channel estimation memory reset points but not in between, said plurality of antenna elements including at least a first antenna element and a second antenna element each of which can be used independently; and instructions for causing the switching module, during a first period of time, to switch between said first and second antenna elements on at least some signal boundaries corresponding to base station channel estimation memory reset points which occur during said first period of time to thereby change the antenna element used to transmit signals from said single transmitter signal processing chain, each switch during said first period of time being preceded and followed by at least one dwell, a dwell being a period of time during which said wireless terminal uses a single set of tones to transmit signals to said base station, a different set of tones being used in immediately consecutive dwells during said first period of time. ### Claim 8 A wireless terminal for use in a communications system including a base station, said wireless terminal the comprising: a transmitter processing chain including a switching module for coupling said transmitter processing chain to a plurality of antenna elements, said switching module configured to switch on signal boundaries corresponding to base station channel estimation reset points but not in between, a base station channel estimation reset point being a signal point where said base station transitions between channel estimation intervals and resets a channel estimate included in the base station, the channel estimation performed by a base station in a channel estimation interval immediately preceding a channel reset being independent of the channel estimation performed in a subsequent channel estimation interval immediately following the channel estimate reset, said plurality of antenna elements including at least a first antenna element and a second antenna element each of which can be used independently; and a switching control module configured to control the switching module during a first period of time to switch between said first and second antenna elements on at least some signal boundaries corresponding to base station channel estimation reset points which occur during said first period of time to thereby change the antenna element used to transmit signals from said transmitter signal processing chain. ### Claim 9 (depends on 8) The wireless terminal of claim 8, wherein said switching module switches between said first and second antenna elements according to a predetermined switching sequence. ### Claim 10 (depends on 8) The wireless terminal of claim 8, wherein said transmitter processing chain is an orthogonal frequency division multiplexing (OFDM) signal processing chain. ### Claim 11 A wireless terminal for use in a communications system including a base station, said wireless terminal the comprising: a transmitter processing chain including switching means for coupling said transmitter processing chain to a plurality of antenna elements, said switching means switching on signal boundaries corresponding to base station channel estimation reset points but not in between, a base station channel estimation reset point being a signal point where said base station transitions between channel estimation intervals and resets a channel estimate included in the base station, the channel estimation performed by a base station in a channel estimation interval immediately preceding a channel reset being independent of the channel estimation performed in a subsequent channel estimation interval immediately following the channel estimate reset, said plurality of antenna elements including at least a first antenna element and a second antenna element each of which can be used independently; and switching control means for controlling the switching means, during a first period of time, to switch between said first and second antenna elements on at least some signal boundaries corresponding to base station channel estimation reset points which occur during said first period of time to thereby change the antenna element used to transmit signals from said transmitter signal processing chain. ### Claim 12 (depends on 11) The wireless terminal of claim 11, wherein said switching means switches between said first and second antenna elements according to a predetermined switching sequence. ### Claim 13 (depends on 11) The wireless terminal of claim 11, wherein said transmitter processing chain is an orthogonal frequency division multiplexing (OFDM) signal processing chain. ### Claim 14 A computer readable medium including machine executable instructions, for use in a wireless terminal in a communications system including a base station, said wireless terminal including a transmitter processing chain including a switching module for coupling said transmitter processing chain to a plurality of antenna elements, the computer readable medium comprising: instructions for causing the switching module to switch on signal boundaries corresponding to base station channel estimation reset points but not in between, a base station channel estimation reset point being a signal point where said base station transitions between channel estimation intervals and resets a channel estimate included in the base station, the channel estimation performed by a base station in a channel estimation interval immediately preceding a channel reset being independent of the channel estimation performed in a subsequent channel estimation interval immediately following the channel estimate reset, said plurality of antenna elements including at least a first antenna element and a second antenna element each of which can be used independently; and instructions for causing the switching module to, during a first period of time, switch between said first and second antenna elements on at least some signal boundaries corresponding to base station channel estimation reset points which occur during said first period of time to thereby change the antenna element used to transmit signals from said single transmitter signal processing chain.