Apparatus, method and computer program product for detecting non-synchronized random access channel preamble
A preamble sequence and equipment technology, applied in synchronization devices, digital transmission systems, electrical components, etc., can solve problems such as high false alarm rate
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
Method used
Image
Examples
Embodiment approach 1
[0063] exist Figure 4 At blocks A and B of , each instance of the received ZC code is associated with one of the ZC root / base sequences (indexed by u) used in the cell. These two correlation results are combined non-coherently at block C. For the u-th Zadoff-Chu base sequence, select the strongest peak P from the result of non-coherent merging nc，u . A detection threshold for the result of non-coherent combining is set at block E, such as (αP nc，u ,T n，nc ), where αn，nc is the threshold set by the noise floor. Call it the first threshold. If at block G the result of the non-coherent combination exceeds this first threshold, then at block L a decision is made that a preamble is detected for this uth ZC base sequence. Otherwise, it is decided at block N that no preamble is detected for the uth ZC base sequence. This process is repeated for each of the ZC base sequences used in the cell. If any uth strongest peak exceeds the detection threshold set based on the uth base ...
Embodiment approach 2
[0066] In this embodiment, preamble detection is done in a staged manner. Figure 4 These additional steps are shown in dashed lines. Each instance of the ZC code received is correlated with the ZC root / base sequence (indexed by u) used in the cell at block A and block B, as described above. At respective blocks D and C, these correlation results are combined non-coherently and coherently. In the first stage, tentative soft detection is done for both non-coherent and coherent combined results. This is shown above as Figure 4 blocks H and G, but this only represents the first stage. In a second stage after the first stage, base sequence specific thresholds are adjusted based on a comparison at block I of non-coherent and coherent soft detection values from blocks E and F output from blocks H and G. At block J, the detection threshold is adjusted at least for non-coherent combining, but at block K it may also be adjusted for coherent combining. Hard decisions are then ma...
Embodiment approach 3
[0085] This change is similar to the staged decision description for Case 1 above, except that instead of correlating different, received instances of the same ZC code, the different segments of a single ZC code are correlated with the ZC root / base used in the cell The sequences are correlated, each yielding a partial correlation. Then there are two correlated segments of the received single ZC code. In that method:
[0086] Coherently and non-coherently combine partial correlations, producing two parallel correlation results,
[0087] ● use the peaks from the tentative detections of the two correlation results to make a final preamble detection decision, and
[0088] - Adjust the preamble detection threshold according to the peak value of the non-coherently combined correlation result or according to both the coherently combined and the non-coherently combined correlation result.
[0089] For each Zadoff-Chu base sequence used in the preamble ( u index) individually adjus...
PUM
Login to View More Abstract
Description
Claims
Application Information
Login to View More