Estimation method of signal interference ratio of forward fundamental service channel in CDMA system of FDD mode
A technology for basic services and channel signals, applied in baseband system components, transmission control/equalization, etc., can solve the problem of inability to estimate the mean and variance of service symbol bits, and achieve the effects of resource saving, high calculation accuracy, and simple calculation.
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Embodiment 1
[0105] Embodiment 1: with reference to attached figure 1 . attached figure 1 Described is the closed-loop power control process of the forward fundamental traffic channel. In addition to sending traffic signals (in the case of communicating with the mobile station) to the mobile station (terminal), the CDMA base station will also continuously send pilot signals, synchronization signals, and common control signals to the mobile station.
[0106] Various signals sent by the base station generally reach the mobile station through multipath fading. The mobile station uses a Rake receiver to extract the main components of the multipath transmitted signal. Each FINGER of the Rake receiver extracts a signal of a specific transmission path (corresponding to a specific time delay). A rake receiver aligns the phases of multiple FINGER output signals so that multiple FINGER outputs can be combined into one signal.
[0107] In order to realize the power control of the forward (down...
Embodiment 2
[0109] Embodiment 2: The transmitted PCB symbols and power in each power control group are the same and transmitted simultaneously in two quadrature phases. A standard QPSK receiver can be used to demodulate these symbols. This means that there is a noise component orthogonal to the signal axis that can be used to estimate Nt.
[0110] I and Q are the sampling values of orthogonal I and Q of the PCB symbol (after multipath). Define x and y as:
[0111] x=I+Q (EQ6)
[0112] y=I-Q (EQ7)
[0113] Denote the absolute value of the noise-free received signal component in the PCB as a, then the signal structure (ie, the amplitude range of the signal) can be expressed as:
[0114] {I, Q}={±a,±a} (EQ8)
[0115] Equivalently, on the x-y axis, the signal structure is:
[0116] { x , y } = { ± a 2 , 0 } - - - ...
Embodiment 3
[0131] Embodiment 3: with reference to attached figure 2 . attached figure 2 It is a specific flow chart of estimating the SIR of the forward basic channel using the PCB ONLY method in an actual mobile station. The PCB Only Eb / Nt estimation algorithm can be implemented using DSP firmware. The process of the PCB Only algorithm is relatively simple and consists of the following steps:
[0132] (1) Using the above (EQ6) and (EQ7), sum the orthogonal components of different PCB pairs in the same PCG and perform Σ-Δ sampling on the components:
[0133] x=I+Q (EQ6)
[0134] y=I-Q (EQ7)
[0135] In the formula, I and Q are the sampling values of the orthogonal I and Q of the PCB symbol.
[0136] (2) Multiplication operation (squared) to get Eb and instantaneous Nt estimates:
[0137] The instantaneous estimate of the noisy signal Eb is:
[0138] E b ^ = x 2 ...
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