User's Manual

CHAPTER 2. Overview of SPI-2213

2-6

y Uplink

− Collaborative SM

Collaborative SM is the technology that doubles the frequency efficiency in view

of the SPI-2213 as two MSs with each individual antenna send data simultaneously

by using the same channel.

The SPI-2213 provides the adaptive MIMO switching function which selects the SM or

STC method dynamically for the downlink MIMO function. The SPI-2213 performs

switching based on a value calculated by reflecting the Carrier to Interference and Noise

Ratio (CINR) and transmission success rate sent by an MS.

4T4R with CDD

The SPI-2213 provides the 4T4R with CDD for which the frequency diversity is applied to

downlink by adapting the RRH-2WB that provides the 4Tx/4Rx RF path. The 4T4R with

CDD is that the CDD function is added to the MIMO function, it is divided into the

following two modes according to the MIMO mode.

y Matrix A (STC) + CDD

y Matrix B (SM) + CDD

The SPI-2213 switches dynamically to the two 4T4R with CDD modes given above

depending to the CINR and transmission success rate reported by an MS. At this time, the

Collaborative SM (CSM) is applied to the uplink.

Figure 1.4 4T4R with CDD (Matrix A + CDD mode)

OFDM

Cyclic Prefix

Data A

Cyclic Prefix

Cyclic

Delay

Receiver

Data A’

Data A (Delayed)

Data A’ (Delayed)

RAS