Some information about soft switchover and macro diversity

Macro diversity

In wireless communication, macro diversity refers to the situation where multiple sending antennas or multiple receiving antennas transmit the same signal, and the distance between these antennas is much greater than the wavelength. In a cellular network or wireless LAN, these antennas can be located at different base stations or access points.
Macro diversity aims to combat fading and increase the intensity of received signals.
The following is an example of macro diversity:
CDMA, soft switch.
UMTS, more soft switch.
OFDM, based on SFN and dsfn ).
802.16e, macro diversity switching (mdho ).

Diversity Receiving Technology

Diversity receiving technology means that the receiver can receive multiple input signals at the same time, which carry the same information and sufferDecline is irrelevant. The receiver decrypts these signals separately and merges them according to certain rules to greatly reduce the effect on channel fading.

What is rake multi-path diversity technology?

Mobile communication is carried out in a complex radio wave environment. How to overcome the multi-path Fading Caused by radio waves is another basic problem of mobile communication. In CDMA mobile communication systems, because of the wide signal bandwidth, we can identify more subtle multi-path signals in time and adjust the weights of the identified signals to enhance the signal after synthesis, in this way, the negative effects of multi-path fading channels can be greatly reduced. This technology is called rake multi-path diversity receiving technology.
To achieve RAKE reception in coherent form, an unmodulated pilot signal must be sent so that the receiving end can estimate the phase of the multi-path signal under the conditions of known data, then, the maximum signal-to-noise ratio (SNR) of the coherent method is merged. The WCDMA system uses user-specific pilot signals, while the CDMA 2000 downlink uses public pilot signals. user-specific pilot signals are only used as an alternative for systems that use smart antennas, the uplink channel uses the user-dedicated channel for the channel.

Another important embodiment of Rake multi-path diversity technology is macro diversity and over-range soft switching technology.. When the mobile station is in a switchover status, the base station involved in the switchover sends the same information to the mobile station. The mobile station combines the multi-path signals from different base stations for diversity, in this way, the quality of the received signal is improved when the mobile station is in a cross-region switch, and the data during the over-region switch is not lost. This technology is called macro diversity and over-region soft switching. Both the WCDMA System and the CDMA system support macro diversity and over-zone soft switching.

Uplink macro diversity

In the uplink direction of soft switching, there may not always be soft merge gains. According to the definition of standard soft switching, soft switching refers to switching between different node B, the switchover of different sectors under the same node B is called a more soft switchover, so the soft switchover uplink, although it is also the signal that two or more base stations receive the UE, however, because the demodulation process is performed at the physical layer (Node B), the merging here can only be selected by RNC For frames on one link (selective merging ), this process still belongs to macro diversity, but does not bring soft switching gain.