Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Differential Amplify-and-Forward Relaying Using Linear Combining in
  Time-Varying Channels   Differential encoding and decoding can be employed to circumvent channel
estimation in wireless relay networks. This article studies differential
amplify-and-forward relaying using linear combining with arbitrary fixed
combining weights in time-varying channels. An exact bit error rate (BER)
analysis is obtained for this system using DBPSK modulation and over
time-varying Rayleigh fading channels. The analysis is verified with simulation
results for several sets of combining weights and in various fading scenarios.

24
The categories of this paper are: dg-ga
13
The categories of this paper are: quant-ph
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
17
The categories of this paper are: q-fin
21
The categories of this paper are: adap-org
37
The categories of this paper are: supr-con
0
The categories of this paper are: hep-ph
25
The categories of this paper are: patt-sol
19
The categories of this paper are: eess
27
The categories of this paper are: comp-gas
16
The categories of this paper are: stat
22
The categories of this paper are: chao-dyn
7
The categories of this paper are: hep-th
20
The categories of this paper are: acc-phys
23
The categories of this paper are: solv-int