Given a BIBD(v,k,A) we can construct a directed BIBD(v,k,A*) by writing each block of the BIBO twice, the second time in the reversed order. Here we prove the analagous expected but useful result that if a BIBD(v,b,r ks,k,A) exists, then a RCOBIBD(v,k,A *} also exists. A nonexistence result is also given.

Broadband Fixed Wireless Access (BFWA) systems enable services such as high-speed data communication, high quality voice/video conferencing and high-speed Internet access in areas where a wired link is not possible. However, the BFWA channel is a slow fading channel having deep frequency selective fading caused by clusters of scatterers in the environment that introduce intersymbol interference...

Wireless Ad hoc networks represent a powerful telecommunication infrastructure that is being exploited for enabling general wireless networking connectivity for a variety of significant applications, e.g., military applications, industrial automation, sensor networks, vehicular networks, applications in case of disaster, etc. The distributed and flexible architecture of wireless ad hoc networks...

A balanced incomplete block design (BIBD) [1] with parameters 2-(v, b, r, k, λ) (short 2-(v, k, λ)) is a pair (V,B) where V is a v-set (elements are called points) and B is a collection of b k-subsets (elements are called blocks) of V such that each point is contained in exactly r blocks and any pair of points is contained in exactly λ blocks. A Hadamard matrix of order n is an n × n (1,−1)-mat...

Beautifully Ordered Balanced Incomplete Block Designs, BOBIBD(v, k, λ, k1, λ1), are defined and the proof is given to show that necessary conditions are sufficient for the existence of BOBIBD with block size k=3 and k1=2 and for k=4 and k1=2 except possibly for eleven exceptions. Existence of BOBIBDs with block size k=4 and k1=3 is demonstrated for all but one infinite family and the non-existe...

The necessary conditions for the existence of a super-simple resolvable balanced incomplete block design on v points with block size k = 4 and index λ = 2, are that v ≥ 16 and v ≡ 4 (mod 12). These conditions are shown to be sufficient. © 2006 Wiley Periodicals, Inc. J Combin Designs 15: 341–356, 2007