2.5 Modulation

This chapter is intended to give a short introduction to the various modulation schemes used in advanced mobile communication. This chapter serves merely as an introduction, for more detailed description and in-depth mathematical descriptions please refer to [7] and [8].

The ever increasing demand on higher and higher data throughput over the air interface is a never ending challenge. As described in Section 2.6 new advanced antenna configurations have been applied to support HSPA+ and LTE in order to maximize that throughput over the air interface.

2.5.1 Shannon's Formula

Shannon established the theoretical maximum data rate over the radio channel, known as the channel capacity. By applying Shannon's RF channel calculation to a radio channel we can calculate the channel capacity (C):

img

C is the channel capacity

BW is the available bandwidth

S is the Signal Power

N is the Noise Power

From Shannon's formula we can see that there are two parameters limiting the capacity of the radio channel. The limiting factors are the bandwidth of the channel (BW) and the quality of the channel, the Signal to Noise ratio (S/N, SNR).

Without diving into the deep mathematical details, we can see that in order to increase the throughput of the data by increasing C, the capacity of the channel of a given bandwidth we will need to increase the Signal to Noise ratio (and by applying multiple ...

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