Transmit diversity is radio

Radio

Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...

 communication using signals that originate from two or more independent sources that have been modulated

Modulation

In electronics and telecommunications, modulation is the process of varying one or more properties of a high-frequency periodic waveform, called the carrier signal, with a modulating signal which typically contains information to be transmitted...

 with identical information

Information

Information in its most restricted technical sense is a message or collection of messages that consists of an ordered sequence of symbols, or it is the meaning that can be interpreted from such a message or collection of messages. Information can be recorded or transmitted. It can be recorded as...

-bearing signals and that may vary in their transmission characteristics at any given instant.

It can help overcome the effects of fading

Fading

In wireless communications, fading is deviation of the attenuation that a carrier-modulated telecommunication signal experiences over certain propagation media. The fading may vary with time, geographical position and/or radio frequency, and is often modelled as a random process. A fading channel...

, outages, and circuit

Electronic circuit

An electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, connected by conductive wires or traces through which electric current can flow...

 failures. When using diversity transmission and reception, the amount of received signal improvement depends on the independence of the fading characteristics of the signal as well as circuit outages and failures.

See also

• Antenna diversity
  Antenna diversity
  Antenna diversity, also known as space diversity, is any one of several wireless diversity schemes that uses two or more antennas to improve the quality and reliability of a wireless link. Often, especially in urban and indoor environments, there is no clear line-of-sight between transmitter and...
  
  
• Diversity gain
  Diversity gain
  In wireless communications, diversity gain is the increase in signal-to-interference ratio due to some diversity scheme, or how much the transmission power can be reduced when a diversity scheme is introduced, without a performance loss. Diversity gain is usually expressed in decibel, and sometimes...
  
  
• Diversity scheme
  Diversity scheme
  In telecommunications, a diversity scheme refers to a method for improving the reliability of a message signal by using two or more communication channels with different characteristics. Diversity plays an important role in combatting fading and co-channel interference and avoiding error bursts...
  
  
• Dynamic Single Frequency Networks (DSFN)
• Macro diversity
• Multiple-input multiple-output communications (MIMO)
• Single frequency networks (SFN)
• Space-time block coding based transmit diversity
  Space-time block coding based transmit diversity
  Space-time block coding based transmit diversity is a method of transmit diversity used in UMTS third-generation cellular systems. STTD is optional in the UTRAN air interface but mandatory for user equipment...
  
   (STTD)
• Soft handover
  Soft handover
  Soft handover or soft handoff refers to a feature used by the CDMA and WCDMA standards, where a cell phone is simultaneously connected to two or more cells during a call. If the sectors are from the same physical cell site , it is referred to as softer handoff...