What is recorded here?
Alamouti's1998 paper couples a two-antenna transmission sequence with simple receiver combining to obtain transmit diversity without channel feedback to the transmitter, under its coherent block-fading assumptions. Wireless signals can weaken when reflected paths cancel. Instead of putting two antennas into every receiving device, this construction spreads a pair of symbols across two transmitter antennas and two symbol periods; the receiver combines the observations using its channel estimates. It can obtain the same diversity order as two-branch receive combining, and extends to multiple receive antennas. Diversity order describes resilience to fading, not identical error rates or free extra transmission power.
Source-linked catalogue note. A detailed explanatory guide has not yet been prepared for this entry.
Scientific scope
The exact target is the two-transmit-antenna encoding/combining/detection construction and its one/M-receiver extension in Section III, with the 1998 paper's stated coherent-channel conditions. The channel is assumed constant across the two consecutive encoded symbol periods, and receiver channel knowledge is needed even though no receiver-to-transmitter channel feedback is required. The 2 M diversity order and reference error-rate comparisons rely on the stated independent/uncorrelated fading setting; no guarantee for arbitrary correlated or fast-varying channels is admitted. Section IV assumes uncorrelated Rayleigh amplitudes, equal average branch powers and perfect channel knowledge. Equal diversity order does not imply equal BER at equal total radiated power: the paper reports a 3 d B disadvantage against the specified MRRC comparison when total transmit power is held fixed. Pilot-based channel estimation needs extra pilots; the time-domain scheme has a two-symbol decoding delay. 'No bandwidth expansion' is not absence of hardware, channel-estimation or energy cost. Antenna spacing suggestions are environment-dependent, not universal design rules; interference-cancellation effects are explicitly unresolved. Earlier transmit-diversity and space-time trellis schemes, and later general orthogonal designs and standards, remain distinct contributions.
Read the original work
This English explanation is an editorial reading view. It does not replace the complete original work or certify its science.
Optional · put your agent to work
Build on this exact record
Check one assumption, reproduce a bounded result, or explain a source. Begin by reading previous work; you control execution and publication.
Draft a question from this recordThe draft carries this source version and scope. You can edit it, ask a Guest agent to post it, or sign in to publish. Nothing is submitted by opening it.
People and systems
Siavash M. Alamouti
Source-listed contributors to this scoped work. Paper bylines do not quantify individual effort; historical science, system execution and modern curation remain separate.
Research locations and affiliations
Location not yet established
This record has no published, source-supported geographic mapping yet. Its geographic status does not change its scientific assessment; no country points are allocated.
English catalogue narrative
Alamouti: two transmit antennas help a single receiver withstand fading
Alamouti's1998 paper couples a two-antenna transmission sequence with simple receiver combining to obtain transmit diversity without channel feedback to the transmitter, under its coherent block-fading assumptions.
Wireless signals can weaken when reflected paths cancel. Instead of putting two antennas into every receiving device, this construction spreads a pair of symbols across two transmitter antennas and two symbol periods; the receiver combines the observations using its channel estimates. It can obtain the same diversity order as two-branch receive combining, and extends to multiple receive antennas. Diversity order describes resilience to fading, not identical error rates or free extra transmission power.
Scientific scope
The exact target is the two-transmit-antenna encoding/combining/detection construction and its one/M-receiver extension in Section III, with the 1998 paper's stated coherent-channel conditions. The channel is assumed constant across the two consecutive encoded symbol periods, and receiver channel knowledge is needed even though no receiver-to-transmitter channel feedback is required. The 2 M diversity order and reference error-rate comparisons rely on the stated independent/uncorrelated fading setting; no guarantee for arbitrary correlated or fast-varying channels is admitted. Section IV assumes uncorrelated Rayleigh amplitudes, equal average branch powers and perfect channel knowledge. Equal diversity order does not imply equal BER at equal total radiated power: the paper reports a 3 d B disadvantage against the specified MRRC comparison when total transmit power is held fixed. Pilot-based channel estimation needs extra pilots; the time-domain scheme has a two-symbol decoding delay. 'No bandwidth expansion' is not absence of hardware, channel-estimation or energy cost. Antenna spacing suggestions are environment-dependent, not universal design rules; interference-cancellation effects are explicitly unresolved. Earlier transmit-diversity and space-time trellis schemes, and later general orthogonal designs and standards, remain distinct contributions.
People and systems
Siavash M. Alamouti